Efficient speakers?
Closed: New threads not accepted on this page| Thread | Last Poster | Posts | Last Post | |
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| Archive through October 01, 2007 | Peter Galbraith | 100 |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2056 Registered: Feb-04 | Am I helping you any, PG? Absolutely! You keep on hunting the net to pursue your creating energy out of nothing rant. Priceless! |
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Platinum Member Username: WingmanaliveA pic is worth 1000 posts!! Post Number: 10371 Registered: Jun-06 | I'm jumping on this bandwagon lol. |
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Silver Member Username: DavidpaPortland, Oregon US Post Number: 475 Registered: Nov-05 | yeesh! I just stop by for a sec to give a laymans point of view. AND.....................BAM! The only thing I see here, is Wiley is getting exactly what he looks for, free entertainment at others expense, and time. I should stop by more often! For popcorn! I said.................... "a 50W amp will drive any speaker. But if you mean drive loudly, even efficient speakers wont get too crazy." to be clear, notice the "too crazy part". Also "Theres more to it, but that is the simple version" The reason for the last statement from me is simple. Most people, including myself, to some degree, have no idea what sensitivity, efficiency, Db levels, resistance, capacitors, heat sink, dynamics etc. etc. etc. REALLY mean, or the actual science behind it, including all the math involved. Most just want to know the basics, or a simple answer, which, on occasion, I feel I can give a short, simple understandable answer. I learn alot from articles Jan has posted, as well as Jans well thought out responses to many questions brought here, that are directly related to audio. I wish I could stop by more, but, since I dont plan on being a scientist, chemist, or audio engineer, I think my time with my own equipment will do just fine. And, on occasion, if I see something I might be able to contribute to, and have Jan fill in the details if they are needed, I know whomever is seeking the finer details, will be in good hands. Simple as that. BTW, hey everyone! Next bags on me! |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2057 Registered: Feb-04 | That's fine David. My simple point to you was simply that you can get crazy loud on 50W. High-sensitivity speakers typically mean , to me, sensitivities reached by horn-loaded designs: 100 to 105 dB, sometimes more. You may not have a feel for what 50W into a 105 dB sensitivity speaker may sound like. In terms you can relate to, it's equivalent to 2000W in a 89-dB home speaker. Wouldn't that be crazy loud? ;-) |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1013 Registered: Apr-06 | I bet Andre wouldn't be impressed. |
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Platinum Member Username: WingmanaliveA pic is worth 1000 posts!! Post Number: 10375 Registered: Jun-06 | He's still saving......... |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1015 Registered: Apr-06 | Next he'll need to save for a hearing aid. |
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Platinum Member Username: WingmanaliveA pic is worth 1000 posts!! Post Number: 10377 Registered: Jun-06 |  |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11408 Registered: May-04 | . All I have time for right now: "Here's some speakers that must be - what? - 97% efficient? 106 dB sensitivity. Could be around 15 to 20% like other horn-loaded systems." If 100% = 108dB, where does the other 80-85% come from in 2dB? It's your math, PG, not mine. What happened to the 100% at 108 stuff? Yeah, I know, it seemed low when you pulled it out of your @ss. So, what about this 2dB thing? * "You keep saying the math is wrong but haven't told anybody what is wrong about it." "If you only wish to think your speakers are 90% efficient, then you have proven nothing. I have never stated that. You made that up." It's your "108dB", PG, not mine. I don't have to make anything up when you supply me with the ammunition. How can I tell you how your equation is wrong when I'm telling you there is no simple equation that says if X is this, Y is that? Now you want me to make stuff up too? I don't do that, ask anybody but wiley. * "You keep repeating stuff I never said until people start believing I actually said it!" They can go back and look at what you said. It's the fact you don't believe you said it that's amazing. * "I didn't defend him specifically, as in I didn't jump in to save my buddy. I jumped in because I saw you were abusing someone again." So, wiley's not your buddy. Sorry, wiley/jimbob/jjj, nobody wants to have anything to do with you. Quite understandably so. Let's try it like this, PG. You see a person being robbed at gunpoint. Do you jump in and take the bullet because you are defending the other fellow or because the gunman is "abusing" someone? You're dead either way. And, PG, you're getting closer to dead with each and every post. Same as always. PG, it's none of your business what transpires between me and wiley. wiley had more than enough to say in his own ... aw, hell, I can't even say the word any more. He didn't defend himself, he insulted everyone. And you haven't said a word about that, PG. That's what's got me so p!ssed off! You jump down my throat days after the affair and you totally ignore him. You are a hypocrite and a liar. Am I calling you names when I point out the truth? Just say you hate me and then leave. * "112dB headphones, PG. Small but if we got enough of them, we'd be able to sell the electricity back to TXU. Repeating a falsehood again so people start believing it?" Good come back, PG. * "Tell you what, if those headphone really output 112 dB at 1m with 1W then I'll give you $1000." Headphones aren't measured at one meter. Didn't you know that, PG? The point is, they are 112dB sensitivity. Really, PG, you should have done better on that one. * "Here's possibly what's got JV up in knots: - Typical speakers are said to have around 1% efficiency and 88-89 dB sensitivity. - I said that, without changing the dispersion pattern, there is a direct relation between efficiency and sensitivity. - JV apparently denies this is possible." Apparently?! You're not sure? Here's one thing, PG. You keep dancing back and forth between specifications that relate to raw driver and speaker systems. They are very different things and if you would answer a few of the questions I posted this afternoon - instead of ignoring them because they're too tough - you might begin to understand what I'm saying. But that wouldn't fit your agenda; would it, PG? Your agenda is to argue in circles like a dog with its tail and never place any effort into comprehension. You simply don't know what you're talking about, PG. And the sad thing is, you aren't even trying. The really sad thing is - I don't even have to try to show how worng you are. * "I said that, without changing the dispersion pattern, increasing efficiency 100-fold results in a direct relation to sensitivity showing an increase of 20 dB. - JV says my math is wrong but doesn't say where. A speaker with 88 dB sensitivity changed to magically be 100% efficient would work out to 108 dB (88 + 20 = 108 dB). Is this math wrong? It's a simple addition." You've said a lot of things. Most of which doesn't make sense. It is not my fault I can't follow nonsense or make it correct when it's totally F'd up! Let's try this, real slow, PG. I never said 88 plus 20 would not add up to 108. I said that is not the way to convert efficiency into sensitivity and it is not the number for a 100% efficient speaker. Go back and look. That is what I said. Even you are agreeing with me on that now. "106 dB sensitivity. Could be around 15 to 20% like other horn-loaded systems." Once again, it's one or the other but not both. * "But there is no contradiction to resolve. I pointed out multiple times that the dispersion pattern affects the density of acoustic energy, and therefore sensitivity. He seems to have missed that several times. I also pointed out that 1% is a rough number only." Uh, what?! * "Start with 89 dB instead of 88 dB (He said 88-89 dB) - Assume the Klipschorn has 12% efficiency, that's an 11 dB gain over 1%. Math again, where is it wrong?" I don't have a clue. Where'd you get the 11dB out of an 11% gain in efficiency? Each dB is now 1% gain in efficiency? Oh, my! So now a 100dB speaker is 100% efficient?! PG, you're loosing me here. * "Now change the dispersion pattern of the Klipschorn to beam the sound into an concentrated area, and you might get 4 dB out of that. - There you go: 104 dB." From this afternoon's questions that PG keeps avoiding; 2) Can someone explain just how "sensitivity" is measured? And what the term means? PG, I am just about in tears here with your math. 4dB by beaming the dispersion?! Really, PG. Why am I bothering? Answer that one question I asked this afternoon, PG. Then we can proceed. Honestly, you've got so many balls in the air trying to prove me wrong that I don't really want to be around when they all finally hit the ground. Speaking of being around, where's your little non-defensible buddy? I notice he's not helping you with this math. He's probably lost too. This is one time I can't blame him. * "How hard was that?" ROFL! * "There goes your king fellas. He's not so good with actual numbers after all." Uh, no, I guess not. Not with those numbers at least. Care to answer some of my questions? Then I'll make up some of my own numbers just like you did. * "I have credentials to teach at universities and I supervise M.Sc. and Ph.D. student." WE ARE DOOMED! DOOMED I TELL YOU! PG, do you have a badge and a decoder ring too? Woowooowooo! * "So I'm not going to take the little insults from Mr. Vigne when he doesn't have a leg to stand on." Since I have two and that's more than enough for this debate, are you leaving now? . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2059 Registered: Feb-04 | I'll keep this real simple now. Down to bare bones... I wrote: - Assume the Klipschorn has 12% efficiency, that's an 11 dB gain over 1%. Math again, where is it wrong?" You replied: I don't have a clue. Where'd you get the 11dB out of an 11% gain in efficiency? Each dB is now 1% gain in efficiency? Oh, my! So now a 100dB speaker is 100% efficient?! PG, you're loosing me here. Exactly. You don't have a clue. You don't have a clue how going from 1% to 12% (a 12-fold increase in efficiency) corresponds to a 11 dB increase. That simple high-school level math is above your head. It' wouldn't be so funny if you didn't persist in being so obnoxious and laughing at me about it. The fact that the only math you are able to put together to get to my answer would be that 11% means 11 dB is rather sad. I'm sorry to say that the math is correct. My repeating it won't convince you so perhaps someone will chime in and admit that it is, in fact, correct. Then you'll make a fuss about something else, the master of disguise that you are. And you even managed to resort to big fonts too. Wow. Same old tired JV. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11409 Registered: May-04 | . Yeah, I can see why you wouldn't want to have to answer any of the other stuff. Particularly why you haven't said anything to wiley. That's got to be sticky to get out of. OK, somebody 'splain it to me. As I read PG's new equation I'm seeing each 1dB increase in sensitivity as a 1% increase in efficiency. To me, that would mean a 2% efficient speaker would also be a 2dB speaker and a 100dB speaker is 100% efficient. What am I missing? And tell if you think PG now says a 104dB speaker is 80% efficient or 10% efficient. He's got me very confused. Didn't he say a 108dB speaker was 100% efficient? Then didn't he say a 106dB speaker is 15-20% efficient? But he had denied a 104dB speaker is 10-12% efficient. Right? And has he answered where all that efficiency comes from in a few dB? Anybody? PG, why don't you work on those questions I asked this afternoon? Since you understand this so well, they should be a snap. . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2060 Registered: Feb-04 | OK, somebody 'splain it to me. I'll spell it out and someone can confirm. The gain from 1% to 12% expressed in dB is: 10 * log(12%/1%) = 10 * log (12) = 10 * 1.079 = 10.79 dB or rounded off to 11 dB. Didn't he say a 108dB speaker was 100% efficient? A theoretical 100% efficiency speaker with the same dispersion pattern as a 1% efficient 88 dB sensivity speaker would have 108 dB sensitivity. Since we both agree that this theoretical number is low, then something else must be different. Namely the dispersion pattern. mid-100 dB sensitivity speakers tends to be more focused in their dispersion than typical 89 dB speakers. Therefore they can reach these high sensitivity without 100% efficiency by focusing the acoustic energy in a smaller space. Then didn't he say a 106dB speaker is 15-20% efficient? In real-life, yes. They are more more focused in dispersion than typical lower sensitivity cone speakers. But he had denied a 104dB speaker is 10-12% efficient. I didn't deny it. I didn't search for that figure and it wasn't relevant to my central argument that efficiency and sensitivity are intimately related. And has he answered where all that efficiency comes from in a few dB? Yes, I did. PG, why don't you work on those questions I asked this afternoon? Because they don't interest me at the moment. I actually came to the forum to ask a question in another section, but it wasn't answered. If you had asked me to explain in this calm and rational manner, I would have. I much prefer this tone of discussion. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2061 Registered: Feb-04 | Let me add something what might help you see where my math is from. Earlier you wrote: Each three dB increase or decrease in system sensitivity indicates the gain or loss of what would be half or twice the amount of power. Maintaining a 50 watt output capacity, switching from a 88dB speaker to an 91dB speaker would be the rough equivalent of switching to a 100 watt amplifier. Plug that into my equation above. Switching from 50W to 100W yields a 3 dB increase, right? 10 * log (100W /50W) = 10 * log (2) = 10 * 0.30103 = 3.0103 dB That's where your 3 dB come from. As you can see 3 dB for power doubling is a close approximation. The factor that is exact is 10 dB for a factor of 10 increase in power: 10 * log(10) = 10 * 1 = 10 dB As you can hopefully see, my math wasn't wrong. And, again hopefully, someone else will chime in to confirm the above. |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1016 Registered: Apr-06 | "2) Can someone explain just how "sensitivity" is measured? And what the term means? " As I stated in my original post, there isn't much of a standard for reporting the number. However, the NRC is more or less the easiest method to get repeatable results with, so I'll go with that. To figure it out, the NRC first pops the speaker in an anechoic chamber, and feeds it a 2.83 volt input (1 watt at 8 ohms, 2 watts at 4 ohms; given the variations in speaker impedance, actual wattage could vary quite a bit). They pop a microphone a meter in front of it on axis and measure its output from the usual 20Hz to 20kHz. They then average the output through a specific range (300Hz to 3000Hz), and that is the sensitivity. What does it say? More or less, it says how loud the speaker will get on axis between 300Hz and 3000Hz in an anechoic chamber at a distance of 1 meter. It hopefully gives you an idea of how loud the speaker will get with a certain amount of power as compared with other speakers measured the same way. However, it doesn't take into account dispersion; it doesn't take into account any significant peaks or dips that could throw off the average value. As such, it isn't perfect, like most things in life. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11411 Registered: May-04 | . Thank you, Stephen. PG, since all speakers are measured on axis at the one meter distance, I don't believe your limited or concentrated dispersion has anywhere close to the amount of change in efficiency as it relates to sensitivity you suggest. Higher sensitivity speaker systems employing horn loading, front or back loading, are not necessarily more efficient in the operation of the driver but rather benefit from the horn acting as an acoustic transformer. Front loading the driver has the effect of limiting dispersion, I agree. However, back loding the driver does not stricly affect dispersion and yet still increases the sensitivity of the system by using the horn loading still as an acoustic transformer. This would seem to disprove your ideas. There's a fudge factor there but I don't believe your theory holds up. The drivers chosen for horn loading do tend to be more efficient however. The mechanics of the driver have changed and not necessarily the dispersion characteristics. How else do we go from an 88dB driver to a 92 db driver without the benefit of a horn? A more efficient driver tends to have lighter diaphragm material combined with more efficient motor assemblies. The efficiency of the motor assembly is highly relevant to our discussion and has nothing to do with limted dispersion of the system. How does this fit into your dispersion theory since this can be applied to a simple cone driver to raise the efficiency of the driver a few per centage points? I don't remember the basic sensitivity of the K'horn drivers, obviously the low frequency system has the largest benefit from the horn where dispersion is much less of a factor. As you said, this doesn't result in a 100% efficient driver but rather a more efficient system overall. As I said, this does not make for a simple equation that says this amount of sensitivity will equal this amount of efficiency. More information is required just as in determining what changes when enclosure volume and bass extension are changed, therefore making an incomplete equation without the last variable. I'll route through some of my old Klipsch "Dope from Hope" papers to see if I can find more on horns/sensitivity/efficiency. One problem I have with your theory is the effect of dipole or omni-directional speakers is also higher "in room" than a monopole due to the higher amount of reflected energy at the listening position. This does not change the basic efficiency of the system, it only changes the in room measurements and perceived level. A basic problem of converting eficiency to sensitivity is the change from electrical energy to acoustic anergy and the inherent losses involved in that transduction of energy. * "But he had denied a 104dB speaker is 10-12% efficient. I didn't deny it." You may not have outright denied it but you certainly weren't in the mood to accept it. * "And has he answered where all that efficiency comes from in a few dB? Yes, I did." No, I don't believe you did. Your 106dB system with horn loading is still, from what you acknowledge, a 20% efficient system. Dispersion has already been taken into account. I first of all find your figure to be on the low side of hopeful but still can't figure out how another 2dB increase to your theoretical 100% efficient system can make up the additional 80%. Could you explain? Either a 106dB sensitive horn loaded system is 20% efficient or it's 80% efficient. It cannot be both depending on the acoustic loading of the driver. Your theoretically 100% efficient system (or is it a driver only?) doesn't allow for higher than 108dB sensitivity speakers used in P.A. work. They are also going to be horn loaded to gain sensitivity. How do they fit into your theory? Finally, as SM pointed out and I suggested earlier, the electrical sensitivity of a driver or speaker system is measured with a 2.83 volt input. Can you explain why this is relevant to the measurement and how it affects efficiency vs. senstivity? This again seems a highly important factor to take into acount when considering the conversion of sensitivity into efficiency. My questions might not interest you at the moment but they are relevant to our discussion in which you chose to engage. Finally, now that the tenor of the thread has shifted somewhat; what do you have to say to wiley about his remarks on this thread? The ones that contributed to his second banning. And what is your opinion of his return under yet another psuedonym the very day after he was banned for (at least) the second time? This is also relevant to the thread since you decided to make "brash" and whatever it was an issue. I'd like to hear your thoughts on this subject. . |
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Bronze Member Username: SobeeatchPost Number: 34 Registered: Sep-07 | Let it go Vigne. The respected contributors to this forum (present company excluded, of course) have not jumped on your "ban" wagon. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11412 Registered: May-04 | . PG, I would appreciate an answer to that last part of my post. Since you made behavior an issue, it would seem important to hear your views on the issue. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11415 Registered: May-04 | . "JJ Johnson Post Number: 34 Posted on Tuesday, October 02, 2007 - 01:26 pm: -------------------------------------------------------------------------------- Let it go Vigne. The respected contributors to this forum (present company excluded, of course) have not jumped on your "ban" wagon." Ah, I see. Since wiley has already been banned there would be no interest to jjj in this matter. Only by trying to save himself from yet another banishment would jjj have any interest in whether wiley gets banned once again. This would appear to be a de facto admission by jjj that he is indeed the person who has already banned (at least) twice. I never thought I say it; but, thank you, wiley. This will be forwarded to the administrator. Since he is the only person who has to jump on a bandwagon, we'll see if he is interested in your latest posting. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11418 Registered: May-04 | . "Higher sensitivity speaker systems employing horn loading, front or back loading, are not necessarily more efficient in the operation of the driver but rather benefit from the horn acting as an acoustic transformer." "The drivers chosen for horn loading do tend to be more efficient however. The mechanics of the driver have changed and not necessarily the dispersion characteristics." Sorry, in a rush to get that post out I contradicted myself. I meant to draw a distinction between the raw driver and the driver/horn as a system. Here's what I would rather say, "Higher sensitivity speaker systems employing horn loading, front or back loading, are not necessarily more sensitive in the operation of the driver but rather benefit from the horn acting as an acoustic transformer." As I posted in my first comments on this thread, "Ideally, this efficiency specification should only apply to a raw driver and not to a complete speaker system ... " I included the crossover as an energy waster in determining "efficiency" vs. sensitivity in the post. Here I would add the effects of dispersion as another variable in the simple equation PG seeks to show us. I understand the addition of dispersion affects the overall equation. (A vented enclosure will be approximately +3dB more sensitive than a sealed enclosure due to the additional energy "dispered" by the back wave of the woofer and out of the open enclosure. That specification doesn't convey the efficiency of the drivers but rather the sensitivity of the speaker system.) How much dispersion adds to the equation I don't know since speakers are measured on axis in the near field. I can't find an answer to that. I doubt the additional gain made by PG's addition of dispersion to increase his numbers is as real as he would lead us to believe because of how the measurement is taken. However, this does seem to make the equation far less simple since we now have another variable to include. The discussion also seems to be moving freely between efficiency of drivers and efficiency of speaker systems. This also makes the simple equation less than simple IMO. As I said above several times, the relevance of 2.83 Volts makes a large difference in our discussion of efficiency and removes a bit of the on paper calculations from the real world situation. Therefore, anyone with anything to contribute to the matter of 2.83 Volts as a reference would be welcome to add to the discussion. . |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1020 Registered: Apr-06 | Means that a speaker that has a flat FR response when receiving a 2.83 volt input, but has a wild impedance curve will have the same sensitivity at all frequencies, but the actual wattage going into the speaker is going to be very different at any given frequency. Anything I'm missing there? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11419 Registered: May-04 | . A bit, but you're getting there. Do you know why the change was made from quoting acoustic output with "one watt in" to quoting the same with "2.83 Volts in"? Nothing else other than the resulting sensitivity or acoustic output power number changed when this occurred. The reason would be the amount of wattage drawn into the "nominal" impedance of the driver or speaker system. This would be a distinction between the Voltage paradigm of measurement and the power paradigm. Into an 8 Ohm load, 2.83 Volts is one watt. Into a 4 Ohm load, 2.83 Volts is now two watts. "Thus, a speaker can have a sensitivity rating that looks the same as the efficiency rating, but the speaker can be several decibels less efficient if the impedance is lower. This is an easy way to cover up how much power it really takes to drive a speaker, and also creates an expression that moves the efficiency issue into the Voltage Paradigm nomenclature. It would also seem to create a 'buyer be ware' situation: you have to know how to interpret the numbers to get to the truth of the matter." http://www.enjoythemusic.com/magazine/manufacture/0707/ Partially what PG and I disagree over is whether speakers exist only on paper where they do not require voltage and current to operate. My contention is efficiency and sensitivity mean nothing until the driver/speaker are connected to amplifier and voltage and current are applied to the motor assembly of a driver or the inputs of a speaker system. Thus we have separated our arguments into a subjectivist and objectivist debate. "The Objectivist/Subjectivist debate has been raging in audiophile circles for nearly three decades. Objectivists operate exclusively in the Voltage Paradigm while Subjectivists tend to operate in the Power Paradigm." One view makes calculations quite "simple" while the other says, "now wait a minute". . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11420 Registered: May-04 | . SM - The only problem with your post is once again the distinction between a raw driver which is relatively stable in its load and a speaker system which will have a dynamic impedance load and whose acoustic output will vary with load depending on the capability of the driving amplifier. This then even changes with the distinction between a sealed enclosure with a very benign single impedance bump at system resonance and a vented system whose dual impedance peaks at resonance will present an entirely different load to the driving amplifier. This, IMO, makes for a less than simple equation for efficiency vs. sensitivity. . |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1021 Registered: Apr-06 | Gotcha. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2062 Registered: Feb-04 | I'll let people acknowledge that my math is correct before pursuing this. Otherwise I'm just covering the same ground again. As for Wiley. I haven't seen or read any posts that are any more offensive then the run-of-the-mill. As for JJ Johnson, it had not occurred to me that he could be the same person as Wiley, and I haven't read anything inflammatory from him either. I really don't believe it is relevant to the efficiency vs sensitivity issue anyway. The outburst against may have inspired me to first post, but it isn't the source of your not understanding my plain physics argument concerning the relation between sensitivity and efficiency. I try tp explain it again and again in slightly different ways and you never grasp it. So I'll wait for external reviewers to acknowledge that my math is correct, and (hopefully) that the arguments hold up physically. Then perhaps you will take another look at some your counter-arguments and we'll save some time. Otherwise there's really nowhere to go. |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1022 Registered: Apr-06 | Peter: One fundamental problem with your argument is: "'How can they have little to do with each other? How could one double the efficiency and not raise the sensitivity at the same time? If a speaker became 100% efficient, it would have little but to produce a given SPL at 1m at 1W since there is nowhere else for the energy to go. " As was discussed a few posts up, because sensitivity is not measured with a 1 watt input, but a 2.83 volt input, it is very possible to double efficiency and not raise sensitivity. FWIW though, I don't expect either of you have approached this with the intention of having a friendly discussion. As they say "There's nothing more exhilarating than pointing out the shortcomings of others" |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1023 Registered: Apr-06 | I also suspect Jans last post plays a big role in your argument/misunderstanding/whatever. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2063 Registered: Feb-04 | Nah, the voltage vs power is a red herring. We use voltage in sensitivity to level out the playing since that is that amplifiers amplify. But the argument remains the same. I also suspect Jans last post plays a big role in your argument/misunderstanding/whatever. I don't know where you are going with that. The argument stripped to its bare bones is as follows (I can't believe I'm stating this in yet another variation!): Assume 1% of the incoming energy to a speaker gets transformed into acoustic energy, spread over some space, to produce 88 dB measured at 1m. Increase the input power 100-fold to that same speaker, what is the SPL now? Is there any difference in the SPL result whether you raised the power by 100-fold from raising the volume dial or from increasing the efficiency 100-fold? If your answer is no, there is no difference and the SPL will be the same because 100 times more acoustic power will be spread over the same space in both cases, then you must admit that there is a direct relation between efficiency and sensitivity. Increasing efficiency 100-fold increases the sensitivity (tell me the easy-to-answer answer of by how much for bonus points). I'm not going to address the 20% vs 80% issue because it involves the math which JV does not understand. If the above makes sense. re-read every single one of my posts and prepare to go "Ah, so that what he meant." That's really that simple. It's basic physics and conservation of energy. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11421 Registered: May-04 | . "I'll let people acknowledge that my math is correct before pursuing this. Otherwise I'm just covering the same ground again." Whether anyone else does or not, I have several problems with your "math", PG. First, there is no provision for load in your equation. I understand that was not your intention, but what you proved was you could add 88 to 20. Nothing more. I kept repeating the equation is incomplete but you didn't care. Like enclosure volume and bass extension, there's something missing. Even now, you refuse to admit you are wrong. As discussed above, you certainly can change the efficiency of a speaker or driver without changing the sensitivity. Without any recognition of that fact your math, like you, becomes worthless. Second, to get your math to work you made two assumptions. First, you assumed I was correct when I said an average 88dB speaker operated at approximately 1-2% efficiency. You made no effort to prove I was correct and in all other cases adamantly denied I knew anything about which I spoke. It would seem odd then to rely on my numbers as the basis for your equation. Secondly, to get to your pre-determined destination you once again reached around to pull 4dB for effects of dispersion out of your @ss. There is no proof this is an accurate number rather than merely a number that fit your desired result. Every indication would lead me to think that is all it is. I may not remember much from the high school physics class I took over thirty some years ago but I remember Sister Patrick Ann would not have accepted your equation without proof of the baseline assumption that 88dB = 1% efficiency nor the assumption that the reduction in dispersion adds yet another 4dB. Without that proof I believe Sister Patty Ann would have flunked you, PG. Your math has no room for assumptions and I suspect the equations you would need to actually prove the numbers you used would make for something other than a "simple" equation. Which has been my point all along, there is no simple asnwer to the question. Thirdly, your verbal "argument" flits between efficiency of a raw driver and whole speaker systems or parts of a system with no consistency nor any distinctions drawn between one or the others. I doubt your final theory would have drawn a passing grade for a high school term paper. Once again you probably would have flunked. On the other hand, in my first post I offered the advice, "Ideally, this efficiency specification should only apply to a raw driver and not to a complete speaker system ... " Didn't matter to you! Fourth, your figures are all on paper numbers that have as much relation to the real world as wattage from a ht receiver. You are unconcerned that the speaker must be driven by an amplifier in order to actually have a sensitivity spec. That no voltage/no current is assumed is far beyond the real world I work in with my approach. Shorthand version; your "speaker" is on paper only while my speaker might actually make sound. PG, remember when I said these battles we engage in always end the same way? With you getting p!ssy and either storming off or wimpering off after I show how you are wrong? Well, we're at that point again. If you wish we can take a poll to determine whether you are correct and a simple equation is all that is required to tie efficiency and sensitivity together. Or, whether I am right that there is no one simple equation that ties the two together and there is more to consider when faced with the real world situation. Is that required here, PG? If someone reading this thread wanted to know about efficiency, do you think they would find your equation helpful? I stand by my original post on this thread, PG. I think it says everything quite succinctly and covers the bases without extravagance. I can only assume that 80% or 20% question is still something you haven't figured out. PG, you have insulted me once again. That was your intent when you showed up on this thread and you succeeded at doing it several times during the course of the thread. That you took offense at anything I said is remarkable when you insulted me with your first post. Then ... ""You didn't need to insult me but you did. By implying that you are not a physicist?" Yes, PG, by implying that you are superior to me and everyone else who is not a physicist. You have done this to me mulitple times over the course of our battles. You have held your equations over my head and demeaned me with accusations that I am inferior to you if I cannot do the math. I have made it clear on this forum that I am not an engineer nor a designer nor a physicist. I speak in words that the majority of readers will understand. You, however, would make that a mark of inferiority. To you I am an uneducated hick. "There goes your king fellas. He's not so good with actual numbers after all." There's the basic problem, PG. That sounds exactly like what wiley has posted over and over and over. You two want me to be "King" just so you can feel better about tearing me down. When you two are proven to not be the person to trust here on the forum, you both lash out at the person most find helpful. You dislike that I am here and remain here. Both of you find it irksome that anyone finds my posts useful and informative. You and wiley are just alike and wiley is not held in high regard by most on this forum. Don't you get it, PG? When you chided me for not knowing the math most everyone reading your comment probably said, "Well, heck, neither do I." By insulting me you, like wiley, insulted everyone on this forum who didn't meet your tiny, on paper criteria for "smart enough". Your's is a problem I saw many times when selling audio. The too smart, too smug engineer who just must prove their superiority by making someone else feel small. But you just hate it when I don't let you make me feel small; eh, PG? That's why you came to stir up problems on this thread; isn't it? It's why you brought my response to wiley into the discussion. Really, PG, your motives are quite transparent and exceptionally rude. And your hypocrisy and lies are startling to say the least. As I said earlier, it is the fact you don't believe you said it that is amazing. "You're an insensitive self-righteous a$shole." "As for Wiley. I haven't seen or read any posts that are any more offensive then the run-of-the-mill." The latest incarnation of one Dennis Michael Wiley?" "As for JJ Johnson, it had not occurred to me that he could be the same person as Wiley, and I haven't read anything inflammatory from him either." Please, Peter, what sort of fools do you take us for? Well, slink back to your lab where only numbers matter. Teach your students to be just like you. We had another forum member years ago just like you who also found me bothersome. He constantly wanted me to take his word for things when he flashed his credentials. Just as with you I frustrated him when I didn't fall over in awe. He was wrong almost all the time also because he too had no room for the real world, only what his credentials told him. When or if you return, and I hope you don't, please, bring some manners with you. . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2064 Registered: Feb-04 | JV, I didn't even read all of that. Why are you back to being so offensive again? our math, like you, becomes worthless. You are incapable of engaging in any sort of conversation. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2065 Registered: Feb-04 | Cut/paste error. That's your math, like you, becomes worthless. I didn't need to read anything after that. Sorry. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11422 Registered: May-04 | . "Is there any difference in the SPL result whether you raised the power by 100-fold from raising the volume dial or from increasing the efficiency 100-fold?" Yes, if it requires twice as much power in the real world, it makes a difference. "I'm not going to address the 20% vs 80% issue because it involves the math which JV does not understand." A cheap dodge with an even cheaper insult. You're quite the guy, PG. Smug and arrogant but quite the guy. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11423 Registered: May-04 | . "That's your math, like you, becomes worthless." I get an A-. You still are worthless. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11424 Registered: May-04 | . Worthless and very petty. It's best you didn't read further. It's not complimentary |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2066 Registered: Feb-04 | Why are so so upset that you don't understand the math? I'm not trying to demean you, I'm trying to work around it! You said you didn't understand it. Big deal. It explained to me why you didn't understand so I tried to explain without using any math. Let me boost your ego a bit: you know tons of stuff, you've heard lots of gear, you've read and educated yourself quite a bit. You're on top of the heap. Congratulations. But you're not a physicist (no, that's no an insult; anymore than you or I are not a dentist!) and there's some concept that you don't understand and don't have the math skills to work out for yourself. At some point you have to take someone's word for stuff and keep going. But, I'm sorry to say, you get quite defensive when you are told you got something wrong. Why do you even care if when that something happens to fall in a physics or math category where you are not expected to know it all? Is it completely impossible that I might know something you know? Or that someone else knows something you don't? Heck, in my job I'm paid to learn stuff everyday, and to learn from others. And we do it every day without trying to tear the other person down. Yes, if it requires twice as much power in the real world, it makes a difference. You are making stuff more complicated that it needs to be. Q: What happens if you raise the power hundred-fold by raising the volume dial? A: The SPL level goes up 20 dB. Q: What happens if the efficieny rises 100-fold from 1% to 100% and 100 times more acoustic power is created? A: The SPL level goes up 20 dB Q: Is there a difference in SPL whether you raise the acoustic power 100-fold by either raising the input power 100-fold, or raising the efficiency 100-fold? A: No, there isn't. Q: Does that mean that efficiency is directly related to sensitivity? A: Yes, it does. Read all the junk you've said to me over the course of this thread, and then wonder why I don't like you so much. You don't make it easy. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2067 Registered: Feb-04 | Another thing... When you don't understand the math, don't shout insults followed by: your math is worthless, get help from a math student since you have admitted you don't know whether it's right or wrong. Instead, say "I don't understand the math, can you explain that some other way?". The first way is beneath you and the second leads to positive dialog. |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 5406 Registered: Feb-05 | "Heck, in my job I'm paid to learn stuff everyday, and to learn from others." I can relate. I learn something new at work everyday...sometimes from the old vets(which I have become...yikes), and sometimes from new folks. I'm not picky just give me the info I need to be better at my job, works for me. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11425 Registered: May-04 | . I thought you didn't read the rest of the post. Goodbye, PG. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2068 Registered: Feb-04 | So we'll never know whether JV sees reason in the Q&A a few posts above. I assume 'Goodbye' means his involvement in the thread is over. Art, can you see it? |
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Silver Member Username: Mike3Wylie, Tx USA Post Number: 747 Registered: May-06 | I wish I could say this has been interesting. David P. Your post from just over 24 hours ago was the most important to me of any since. I agree with you. I could go through a little effort and prove something, but for what? I could try to answer Jan's questions but that would only create a tangent debate. I really don't care about these measurements. I can recall "listen to the music" when I engaged on this forum. Some points I have considered; 1. I know an incredible amount more now about audio and electronics, dependencies, materials, products, tweaks, etc. than I could have imagined because for this forum (not this thread). 2. Let's assume I knew about 25% of what I know now, when I bought my Apollo, 35 -- 40% of what I know now when I bought my pre-amp, 40 -- 45% when I bought my speakers, 50 -- 60 % when I bought my turntable, 75-80% when I bought my Saturn, and about 95% when I bought my MAC amp. The tuner was dumb luck. I didn't know anything about what I bought when I bought that. 3. My guess is that if I was not so naive I would not have collected some of the gear I have now. I wouldn't trade what I have now for anything. Seriously I would not. It was a journey to get here and I am proud of what I have and the sound I get. 4. I got here because of dealers who are respectable gentleman who know their trade and I put my trust in. 5. I got here because of several members of this forum. Almost everyone who has been here for any length of time has introduced something to me to learn from. 6. Nuck, Frank, John A., stryvn, M.R, Stu, NMyTree, Gavin, Art, Stephen, David, Nick, Christopher, Mike B., Kevin, and too many others have been generous with their help and support. 7. I have found a good friend in Nuck and look forward to listening to music and hitting hi-fi shops with him next chance we get. Scotch is excellent too. 8. Jan stands head and shoulders above everyone to me. It is because of Jan that I have been really able to become "studied" in this hobby of ours. A majority of my tweaks and changes as well as my MAC have been due to Jan's influence. 9. Call me what you want but I will support Jan unfailingly on this forum as Jan is a true friend who has been supportive and patient as I learn and find my way. 10. I am sure others may have folks on this forum who they could feel that way about and I would expect you to support your friends and compadres in a like manner. 11. All I know, and this is truths learned on this forum, is to review the specs for a "loose" idea of whether a speaker might meet your needs. Then listen to it. Some high efficiency speakers are impossible to listen to, some low efficiency speakers take way to much power (think cost of amplifier) to get the sound you are wanting. This whole argument / exchange on this thread will never result in anyone making an informed decision on what speaker to put into their system. 12. I have a pop-corn maker in my media room. Y'all are welcome to come by for some. P.S. It's never been about the math. I have a Theorem which my Geometry teacher in High School I think got published on parallelograms (cool for her I did not care), but my math skills are not going to help me get better music. |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1024 Registered: Apr-06 | I understand what you're saying Pete, but I think you two are having entirely different discussions. You'll note he is referring to efficiency as a raw driver spec for starters. You continue to refer to the efficiency of the total loudspeaker (drivers + enclosure + XO). From his point of view, once you pop that raw driver onto the baffle of a loudspeaker, and connect it to a crossover, the raw driver efficiency spec has a lot less meaning. I don't believe he is disagreeing with most of what you're saying per say. I just don't think he finds it relevant. I could be wrong. It has happened. You on the other hand seem to be making a simple argument that if the overall efficiency of the complete loudspeaker is increased by a certain amount, its output will be increased by that same amount for a given input. I'd say that is pretty much common sense, but what do I know. In any event, I bid you guys goodnight. |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1025 Registered: Apr-06 | PS: I would also note that what Jan has convincingly shown (at least IMO) is that a sensitivity spec does not *easily* correlate to efficiency, be it of the driver or of the system. Differences in dispersion/directivity as well as impedance and how the spec itself is determined preclude that, regardless of how they may or may not be related. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2069 Registered: Feb-04 | You on the other hand seem to be making a simple argument that if the overall efficiency of the complete loudspeaker is increased by a certain amount, its output will be increased by that same amount for a given input. I'd say that is pretty much common sense, but what do I know. Nail on the head buddy. Nail on the head. In any event, I bid you guys goodnight. Goodnight! |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11426 Registered: May-04 | . "When you don't understand the math, don't shout insults followed by: your math is worthless, get help from a math student since you have admitted you don't know whether it's right or wrong." PG, you scream when you claim I am putting words in your mouth. Why do you do the same to me? Clearly, you do would prefer to insult me further. Certainly, you do not understand my argument in this whole affair. I have repeatedly said I cannot make sense of your argument or your equation since parts of the equation are missing and you are sloppy in your language and terminology. Please, PG, your tactic here is quite beneath you. "Heck, in my job I'm paid to learn stuff everyday, and to learn from others." "Instead, say "I don't understand the math, can you explain that some other way?". The first way is beneath you and the second leads to positive dialog." To quote a certain politician, "Well, there you go again." You certainly know how to spread the compliments and establish "positive dialogue", PG, at least for someone too smart and too smug for their own good. Your conciliatory tone is quite at odds with all that has gone before. You didn't seek positive dialogue from the moment you entered the thread. Your intent was to confront me from your first post. And you topped it all with, "There goes your king fellas. He's not so good with actual numbers after all." Tell me where the positive dialogue is in that, PG? Tell me where bringing wiley into the debate is seeking positive dialogue. Is that your idea of reaching out? Apparently, I'm not good with math or words. Why don't you just drop the hypocritical attitude? You are here because you don't like me and you are not going to admit I may have an equally valid point because it would mean admitting disliking me is not as easy as you would prefer. Another reach across the table, eh? Yep, let's keep it positive. Bull! In your intial volley, you asked, "How could one double the efficiency and not raise the sensitivity at the same time?" I showed you how. You do not wish to accept this as a reality. You work on paper. Your speaker makes no sound! Why can you not understand that fact? Real speakers require real voltage and current. Real speakers present a load to the amplifier. Your's do not. They require calculations. If you change the load, even on paper, you change the amount of power required to achieve the same acoustic output. That changes the efficiency. Now, in your world that might not matter. In my world that matters to a tremendous degree. It also matters whether a speaker system has first order filters with few components or fourth order filters with complex, power robbing components. My advice is from the real world while yours is from the make believe world of paper numbers. Why can't you accept that difference? It doesn't make either of us wrong. But it does make both of us more correct. Can you not live with that compromise? Efficiency is an almost bogus number that means little to the sensitivity of the system. It wouldn't exist if not for sensitivity. If I have to make adjustments to the calculation to include dispersion and load, I've crossed from what I consider to be a "simple" relationship. But, then, I'm not good at math. If I have to make it clear I am discussing a single driver or an entire speaker system, I have more to consider than a simple equation. That has been my point since the beginning. You see your argument as correct while dismissing any other view. Is that seeking dialogue? Is it possible someone knows something I don't? Of course, I've never said otherwise. Is it possible my argument is worth consideration in the real world of choosing a speaker system? You seem to think not. So, here is the proposition as I see it being made by you. Admit that PG is correct and I am a dunce and PG will be happy. Sorry, my position stands as I stated it. You've proven 88+20 = 108. Nothing more. I never argued with that equation. You tell me my questions just don't interest you even though I say they are vitally important to the discussion. There you go seeking positive dialogue again. Are you seeing a trend here, PG? Yes, it's all my fault this thread has degenerated into a shouting match. Think again, PG. Here's an offer. Place the information required to establish 88dB = 1% efficiency in simple terms that we can all understand. Since you believe I can't follow your math, this should be an opportunity to show your concilliatory ways and to allow everyone to follow your argument. Do the same with the 4% dispersion gain you used in your math. Explain in simple terms how the additional 2dB gives you the 80% you require rather than insulting me. Then explain how altering the impedance load of the driver/system will not affect the efficiency when more power is required to drive the system to the same acoustic output. That will be a step in a positive direction. . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2070 Registered: Feb-04 | Why would impedance matter if we are using the same speaker, only increasing the power input and output? Why won't you agree or disagree with the simple Q&A as outlined? Why do feel insulted by stating the fact that you don't have a degree in math or engineering? Why do you persist in pushing this 80% issue when I've already addressed it to your unsatisfaction and said I wouldn't address it further until other simple issues were out of the way? It takes two for a shouting match. I'm done with that. If you think I'm seeking you to be shown to be a dunce, then I'm sorry you feel that way but you painted yourself into that corner by calling me names about my correct math. It's not my fault if it reflects badly on you if people see that I'm correct and you were sure I wasn't. The Q&A isn't meant to show you off as a dunce, it's meant to help you understand that all the real-life issues like impedance swing don't have anything to do with the direct relationship between efficiency and sensitivity. You're upset that I don't address those issues, but they are not relevant. I really thought that you'd pick up on the logic a few posts back and breath in a little. But no, every single post is more aggressive attack on your part. I don't think there's anything I could say to make you change your mind on this issue. So again, I ask for others to chime in if they see the logic in it. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11427 Registered: May-04 | . Your speakers don't exist, don't require an amplifier and don't make sound. That resolves all issues in your mind. If that is "logical", then you have your math to fall back on. It does take two to tango and let me remind you how well you know the steps. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11430 Registered: May-04 | . You dismiss my questions because you're just not interested in answering them while believing I am obligated to answer yours. If you would like members to chime in on your logic or math, why don't you clarify just what they are considering? That 108dB = 100% efficiency? Despite the fact that various P.A. speakers operate above that sensitivity. If speakers play above 108dB sensitivity, how do they achieve higher than 100% efficiency? If 108dB doesn't equal 100% efficiency, why should any of the rest of your math be correct? That a 106dB speaker is approximately 20% efficient but a 108dB speaker is 100% efficient? That you can gain 4dB of sensitivity simply by restricting the dispersion when you've shown no proof of that number? It still appears to be a number that was pulled out of the air to satisfy your equation. The fact dispersion affects sensitivity in some manner is not the question. The question is; how did you arrive at 4dB? That 88+20 = 108? No argument has been presented that would contradict that equation? That speakers are perfect and do not require an amplifier? Or, that increasing the power 100% provides a 20dB increase in SPL? On paper calculations would once again prove that equation to be correct. None of us will deny the fact that physical objects obey physical rules. More power in equals more SPL out. To an extent and then everything stops obeying certain physical laws and begins obeying others. Only speakers that do not operate on real world power input will manage SPL increase that in most cases. In the real world most consumer speakers will begin to exhibit dynamic compression at +20dB above baseline sensitivity. The SPL will not go up by 20dB no matter how much you raise the power input. That leaves make believe speakers and large horn loaded systems which are outputting +96dB@2.83 Volts as the only speakers capable of your desired SPL increase. Both of those types of speakers have significant drawbacks for the majority of listeners. One is obvious, they don't make sound, and the other is accepted by choice. That doesn't make the math incorrect, it merely moves your equation back to on paper numbers or speakers with other disadvantages. This would be important in the real world since selling a four Ohm 87dB speaker to someone who desires 118dB levels would in most cases be foolish. But, once again, there are drawbacks to your method of achieving the desired SPL. What are we judging here? That halving the impedance load does not result in a doubling of the power requirement thus making the speaker less efficient for the same acoustic output? Even on paper that proves to be true. You say it's not. That a single driver and a speaker system are interchangeable in the discussion of real world "efficiency"? That "efficiency" is anything other than a "kind of close" approximation of what we obtain from the sensitivity measurement? That there are no meaningful numbers for efficiency beyond ballpark calculations because real speaker systems do present real problems that on paper make believe speakers do not bother with? Those are still the problems I see in your logic and your math. Is that what you would prefer people judge? If not, what? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11435 Registered: May-04 | . "Why would impedance matter if we are using the same speaker, only increasing the power input and output?" Why can't you see you and I are not talking about the same speaker? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11436 Registered: May-04 | . Peter - Let's try this. "Why would impedance matter if we are using the same speaker, only increasing the power input and output?" First, what you describe above doesn't alter the efficiency of the driver, only it's acoustic output by way of increased input power. It is the same speaker only with more power applied. The laws of physics then dictate it will output more acoustic wattage, but, unless I am way off base here, the driver's efficiency remains the same and it will still be the same "X"dB@1meter@2.83Volts driver it always was. It will play louder. Big deal! Second, you are very sloppy about your continued use of the term "speaker". I've consistently drawn a distinction between "driver" and "speaker system". You ignore that distinction and wish to argue they are the same. In my argument, they are not the same. If you understand that, we come much closer together in our arguments. Third, if we take any given driver, you pick, and we try to make the same driver more efficient; how'd we do that? If it's the same driver it must be the same efficiency. If it's a different driver, it can be more efficient. But the same driver is the same efficiency. Unless we alter it to make a driver that is not the same as our orignal driver or we make it into a speaker system. If we add a horn to make a more sensitive "system", we have altered the driver in some way in order to raise the efficiency of the "system". If we add the horn, we have added an acoustic transformer to the newly created "speaker system" and transformers bring their own losses and problems. Unless, of course, we are discussing make believe speaker systems and drivers. They can do many things ordinary, bound by the laws of physics speakers can't do. They can have boundless efficiency because we can continue on with your logical math progression and not be bound by the laws of the real world. Real speaker systems can't do that. Do you see the problem here, Peter? . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2071 Registered: Feb-04 | First, what you describe above doesn't alter the efficiency of the driver, only it's acoustic output by way of increased input power. It is the same speaker only with more power applied. The laws of physics then dictate it will output more acoustic wattage, but, unless I am way off base here, the driver's efficiency remains the same and it will still be the same "X"dB@1meter@2.83Volts driver it always was. It will play louder. Big deal! Fine, so you are in agreement with Q&A #1. Progress has been made. You have increased output by 20 dB by raising the input volume by 100-fold. It's a perfect speaker without compression. If real-world compression worries you, then imagine we started off at 0.01W or that we only doubled the power. No compression occurred. Let's say we doubled the power and raised the output SPL by 3 dB. Now, imaging this fantasy-land speaker where you could turn a knob on it to increase efficiency. If you double the efficiency (since going close to 100% troubles you so much) without changing anything measurable from the outside of the speaker (impedance, dispersion), what happens to the acoustic output? Twice as much gets out so it is raised by 3 dB. Since the SPL is 3 dB higher and the input power has not changed, then the sensitivity has been increased by 3 dB. That's part #2 of the Q&A. Raising the efficiency raises the sensitivity. Therefore the two are related. In the real world, there is no knob to increase the efficiency. You get what you get from design choices and the difficulty of coupling a moving diapram to the surrounding air. Nevertheless both these characteristics of a loudspeaker system are intimately related. If you manage to have one, you have changed the other. Third, if we take any given driver, you pick, and we try to make the same driver more efficient; how'd we do that? Try to think abstractly about the problem for a change. Not considering non-relevant facts does not make me weaker, nor does it make me an ivory tower professor, it helps to conceptualise the problem and find a solution. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2072 Registered: Feb-04 | Second, you are very sloppy about your continued use of the term "speaker". I've consistently drawn a distinction between "driver" and "speaker system". You ignore that distinction and wish to argue they are the same. In my argument, they are not the same. If you understand that, we come much closer together in our arguments. The initial post and I never spoke about drivers; only loudspeakers. I am considering efficiency of the system as a whole. Power goes into the speaker and Acoustic power comes out in the air around the whole loudspeaker. This assumption is fairly obvious from all of my examples. I am also considering the sensitivity of the loudspeaker as a whole, mounted with a sealed volume of air behind it, or ported, or horn-loaded. All these things affect both the overall efficiency and sensitivity, which are intimately related. Do you no longer disagree given the context that loudspeaker efficiency and sensitivity refer to the complete package (as in the initial poster's question)? |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2073 Registered: Feb-04 | If you manage to have one, you have changed the other. I meant to write: If you manage to change one, you have changed the other. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11438 Registered: May-04 | . No! But nice backtracking there, PG. You win the CYA award for the day. * PG: "Why would impedance matter if we are using the same speaker, only increasing the power input and output?" JV: "First, what you describe above doesn't alter the efficiency of the driver, only it's acoustic output by way of increased input power. It is the same speaker only with more power applied. The laws of physics then dictate it will output more acoustic wattage, but, unless I am way off base here, the driver's efficiency remains the same and it will still be the same "X"dB@1meter@2.83Volts driver it always was. It will play louder. Big deal!" PG: "Fine, so you are in agreement with Q&A #1. Progress has been made." Red herring #1. No progress has been made other than someone is scrambling for something to cover themself with. * "You have increased output by 20 dB by raising the input volume by 100-fold. It's a perfect speaker without compression. If real-world compression worries you, then imagine we started off at 0.01W or that we only doubled the power. No compression occurred." If you please, from: Jan Vigne Post Number: 11430 Registered: May-04 Posted on Wednesday, October 03, 2007 - 11:40 am: "In the real world most consumer speakers will begin to exhibit dynamic compression at +20dB above baseline sensitivity. The SPL will not go up by 20dB no matter how much you raise the power input. That leaves make believe speakers and large horn loaded systems which are outputting +96dB@2.83 Volts as the only speakers capable of your desired SPL increase." Baseline, PG. You can't change the rules in the middle of the game. You've tried but people are watching. We live in the real world with real speakers. They aren't perfect. Only make believe speakers and drivers are "perfect". * "Now, imaging this fantasy-land speaker where you could turn a knob on it to increase efficiency." I've never denied you live - and calculate - in a fantasy land. I live in and discuss the real world. Biiiiiig difference! * "In the real world, there is no knob to increase the efficiency." You see, PG, I've always said comprehension was not your strong suit. That real speakers don't behave the way you wish them to in your fantasy land has been my argument from the very first post! It's taken you, what, 90 some posts to come to that conclusion?! Progress has been made?! Unfortunately, I doubt it but PG's found some sheeets. * "If you double the efficiency (since going close to 100% troubles you so much) without changing anything measurable from the outside of the speaker (impedance, dispersion), what happens to the acoustic output?" It can't be done so why argue that it can or that it proves anything other than fantasy land on paper calculations? Good Lord, PG, haven't you paid any attention to what I've said over the last few days? I mean, covering your butt is one thing. This is absurd! And polka dots don't play well on your butt. * "Raising the efficiency raises the sensitivity. Therefore the two are related." Let's get back to basics. You can lower the efficiency of a speaker system by lowering the electrical or mechanical impedance load. You can raise the sensitivity of a speaker system by affecting its dispersion without affecting the efficiency of the raw driver. How does that translate into, "Raising the efficiency raises the sensitivity. Therefore the two are related"? There is no constant there if you make the distinction between driver and speaker system. A point I made on Tuesday, September 18, 2007 - 07:26 pm, when I posted, "Ideally, this efficiency specification should only apply to a raw driver and not to a complete speaker system ... " Comprehension, PG, comprehension. You were too blinded by the desire to take me down a notch by way of your wiley comments to actually comprehend what was posted. You have been pulling stuff out of your butt all along and now you have to cover it while you try to get away unnoticed. We've spent all this time arguing something that was right in front of you and now you admit all your "math" and all your "logic" are ... hold ... a fannnntasyyyyy! Yeeesh! * "Nevertheless both these characteristics of a loudspeaker system are intimately related. If you manage to have one, you have changed the other." No! I can have one and not change the other. I can change one and not change the other. Or, I can change them both. As long as I'm discussing a "speaker system". Can't someone explain this to PG? * "Not considering non-relevant facts does not make me weaker, nor does it make me an ivory tower professor, it helps to conceptualise the problem and find a solution." Ow! I hate it when I hit the floor like that! PG, ... You don't want to know what I think it makes you. It's not very complimentary. * "The initial post and I never spoke about drivers; only loudspeakers. I am considering efficiency of the system as a whole." "Tuesday, September 18, 2007 - 07:26 pm, in response to the original post I stated, "Ideally, this efficiency specification should only apply to a raw driver and not to a complete speaker system ... " My God! PG has dropped the sheet and his @ss is uncovered! Red herring #2. PG doesn't have any consistency in how he describes a "speaker". I've tried and tried to get him to be consistent and to draw distinctions. Did he listen? Anyone?! Hello! Stop laughing and get in here. * "Power goes into the speaker and Acoustic power comes out in the air around the whole loudspeaker. This assumption is fairly obvious from all of my examples." Aw, hell! Do I have to find the post where he relied on limited dispersion for an additional 4dB of efficiency?! It's up there. If you need proof, find it yourself. My head hurts. * "I am also considering the sensitivity of the loudspeaker as a whole, mounted with a sealed volume of air behind it, or ported, or horn-loaded." Yes, you are now describing a speaker system. * "All these things affect both the overall efficiency and sensitivity, which are intimately related." You had me going with you until, " ... which are intimately related." They are but they are unknown variables. That is what I've said, PG, that is what I've said. Speaker systems. Variables. No simple equation. Comprehension skills. Lack of one of the above. * "Do you no longer disagree given the context that loudspeaker efficiency and sensitivity refer to the complete package (as in the initial poster's question)?" Answer #1) You chided me for a misspelled word. Now you include a double negative and expect me to let that pass?! * "Do you no longer disagree given the context that loudspeaker efficiency and sensitivity refer to the complete package (as in the initial poster's question)?" What the hell do you think?! . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11439 Registered: May-04 | . /2{Step riiiight up and geeeeeet your "speeeeeakers"!} Laaaaadies and gennnnnntlemennnn, have I got a deal for you! Two speakers, that's two speakers I say, to choose from and the good news is they're both at the same low, loooow, looooow price! Young man, yes, you! Would you prefer to have speaker #1? This is a lovely low mileage speaker system that is spec'd at 88db sensitivity. That's 1-2% efficiency to you, son! The mid and high frequency driiiivers are mounted on a baffle which reduces their dispersion to half sphere. That's twoooo Pi to you, son! The loooow, looooow, looooooooow frequency driver is back horn loaded to increase the sensitivity of the system by using the dispersed back wave of the driver to magically wrap around inside this here pipe and come out right about ... here! It's gonna be in phase with the direct radiation and thereby increasing the SPL by ... well, let me get back to you on that, son. And the good news is, it doesn't change the efficiency of the driver's motor! How's that sound, son? Yes, m'am! Step right up here. You have a question about this fine, fine product? Oh, yes!, m'am!!! There's more crossover components in there than you can shake a stick at. Power robbing?! Insertion loss? Um ... Well, you see ... Um,.... Away from this little baby?! M'am! You offend me! Didn't you hear me say the efficiency of the driver has not been altered one iota! It has limited frequency response so it won't keep the baby up and will fill a nice sized, er, ... well, a tidy little room. You do keep a nice and tidy little room; don't you, m'am? That's just fine. You look that over. Now, if the rest of y'all would turn your attention to the next marvelous beauty presented here for your consideration. Now, sir, you look like a nice physicist I once ran into. I have just the speaker for you also. It is a fantasy land speaker that has 100% efficiency and, if you play your cards right, it can even achieve more than 100%!!! Do you know what 100% efficiency is, sir. No! well, don't feel bad, neither do I. Hahaha! All of this just for you 'cause I like the way you look, sir. (Though, really, those polka dots are a bit loud.) Nonetheless, this here speaker has no driver. It doesn't need 'em because they only get in the way. Our fabulous fantasy land designers found they could calculate better without those things that just get in the way. Don't you agree, sir, no need for stuff that gets in the way. Uh, yes, sir ... I say, sir, are you paying attention here? It has a frequency response from 0 to 100kHz. (How's those numbers sound, sir? Like a fantasy, eh? Let me tell you, between just me and you, it is a fantasy! One you'll be lucky enough to own if you step right up to the plate here.) This little darlin' will play without dynamic compression unlike those others speakers you may have heard. It's a doozy and the best part is it doesn't take up any room in your home. Because owning is a fantasy!!!!!!! Hahahaha! Ahemmmm, Now there's a feature you don't find in just any old speaker! Let me tell you I've never even seen one like it myself. Hahahahaha! Yes. Ahem, as I was saying ... Just to let you know, I have plenty of the first speaker in stock and ready for delivery. Who'll be the first to take these off .. I mean, own these wonderful speakers. Come on, don't let that 2% efficiency bother you. Most speakers don't do no better! What's that? The second speaker? Aww, it sounds like you have a discerning eye there, m'am. Hahahaha. Naw, naw, they go together like ... well, like efficiency and sensitivity. That's a good thing when you're gonna own a fanstasy land speaker, m'am! That's a wonderful thing. And easy to understand, too! I'm sorry, m'am, you'll have to excuse me. I was distracted by facts over here. Yes, well, the second speaker ... Well, let me explain about the second speaker. Er, um, I mean, well, we've done so well with that model that I'm taking orders and they'll be here in just a fantasy land minute. Just as soon as the company can get some more of those non-existent items needed to make this speaker the absolute fantasy I say it is. Did I mention this here speaker has this little crank on the side? Now, son, nice lookin' shirt there, son, how many of each would you like to buy? . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11440 Registered: May-04 | . Let's see wiley do that! |
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Silver Member Username: StryvnPost Number: 522 Registered: Dec-06 | Now THAT'S entertainment, folks. Peter, I ain't here to argue your math skills but you came in with a chip on your shoulder and something to prove. Congratulations. You remind me of someone else that visited here not long ago that thought he could demand respect by telling us his credentials. Nobody gives a ratsass about who you stand in front of and talk to. You and Gracka should get together and go bowling. Bottom line, I have learned more and had real life sound improvements to my system here at home because of what Jan has contributed to this forum. I trust his years of REAL LIFE experience in and around LIVE MUSIC over your calculator. I know I am not alone. I understand some people don't like his style, but I don't think anybody has any doubts about where Vigne stands and that's ok with me. And again, his sound advice has helped me with my gear. Your arguments and wiley's nonsense...notsomuch. You keep asking for people to chime in. There's my $.02 |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2074 Registered: Feb-04 | You keep talking a big game about being polite, but you don't practice it. I wonder why I keep expecting you to be rationale and you seem to get worse every time. Yet you claim to be the model of perfect conduct. Mr Vigne, I'm very sorry to say that you don't appear to have an ounce of logic in you. I've tried to explain things simply, but you shown yourself incapable of understanding basic physical concepts. Let's pick one and end it here: I tried to remove a new factor that you have decided has to be important. I said: You have increased output by 20 dB by raising the input volume by 100-fold. It's a perfect speaker without compression. If real-world compression worries you, then imagine we started off at 0.01W or that we only doubled the power. No compression occurred." e.g. if 20 dB bothers you, let's try starting at 0.01W or even simply increasing by 3 dB. Instead of following the physical argument, you need to counter with: "In the real world most consumer speakers will begin to exhibit dynamic compression at +20dB above baseline sensitivity.The SPL will not go up by 20dB no matter how much you raise the power input. That leaves make believe speakers and large horn loaded systems which are outputting +96dB@2.83 Volts as the only speakers capable of your desired SPL increase." Baseline, PG. You can't change the rules in the middle of the game. You've tried but people are watching. We live in the real world with real speakers. They aren't perfect. Only make believe speakers and drivers are "perfect". Huh? Trying to change the rules? I'm trying to lay out simple physics for you and you can't see it! Are you going to get compression by starting at 0.01W and doubling the volume to 0.02W? Hint: the answer is no. Compression doesn't occur in this example, fantasy speaker or not. Observers will note that I have been much much more polite than your replies deserve. You keep making fun of me, but you're only making smart people see your lack of logic. I'm done arguing this thread. Not because you are right. Because you are incapable of ever understanding and are too rude to be helped along the way. I let you and your pack of admirers finish off; your style is usually to get in a few more wise cracks at other's expense when you have insulted them so much that they have abandoned the thread. The amazing part is that people admire your conduct! Wow. And you use too much white space when you post; it's annoying. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11441 Registered: May-04 | . "Jan Vigne Post Number: 11395 Posted on Monday, October 01, 2007 - 05:31 pm: -------------------------------------------------------------------------------- ... PG, this follows a common thread when you and I get involved in one of these stupid call outs of yours. The longer you try to defend what you said, the more I will show you that I am correct. Then you'll get all p!ssy and leave. Why not save us some time?" Well, you did what I predicted. I only wish you'd saved us all some time. How many times has this happened, PG? It's always the same scenario. I can watch the arc the thread takes and know when it will turn. In the end, the only refuge you have is to say I'm just thoroughly incapable of understanding your highbrowed logic and then leave the forum for another year. If you do as you have all the other times, you'll be back to say a few more things and then you'll get even piss!er than you are right now. Go ahead. This thread is over as far as you and I are concerned. You have insulted me, you have ignored me, you've told me my thoughts weren't of interest to you, you've called me "King" just so you could try to knock me off some supposed throne you are envious that I somehow possess, you've been told repeatedly other members trust me and no one has said they trust you ... aw, heck; why go on? You've had an average entry on ecoustics for Peter Galbraith. I suspect this will only serve to fire your dislike for me and we'll do this again sometime. Oh, well. Your turn. Then will you leave? And you use too little common sense when you post. It's annoying! . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11442 Registered: May-04 | . I suspect our new member, BS, will be here shortly also. He'll condemn me with words such as, "You keep making fun of me, but you're only making smart people see your lack of logic." Oh, wait. Nope, that's PG. Sorry. Well, wiley/BS will be here soon anyway and say pretty much the same thing. This is too predictable. . |
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Gold Member Username: NuckPost Number: 8828 Registered: Dec-04 | Peter, music does not live on paper, nor does a music reproduction system. A lot of your point are valid underwater or in other experimental circumstances. The difficulty cmes when stereo musicality is involved,when all theorums seem to fall a bit short in execution, that's all. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2077 Registered: Feb-04 | Want to buy expensive speaker wire Nuck? ;-) |
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Bronze Member Username: ZorroPost Number: 62 Registered: Jul-05 | Er, um, I mean, well, we've done so well with that model that I'm taking orders and they'll be here in just a fantasy land minute. Just as soon as the company can get some more of those non-existent items needed to make this speaker the absolute fantasy I say it is. Did I mention this here speaker has this little crank on the side? Wow you really know your stuff Mr. Salesman mmmmm. You know what, thank you but no thank you. You are very well versed and by God you seem to be a very intelligent man with great audio knowledge but.... I sense that you are a very arrogant person who knows very little about being humble or respectful of other people's weaknesses or opinions. I will just take my business somewhere else. Hey what about Best Buy? Lack of knowledge but better people skills not by much but better. Leaving the very famous Mr. Wiley aside, what about all those first timers who came to the forum with simple questions and you insulted them because (in your mind) they did not measure to your great stature of Audio knowledge? I mean after all no one knows everything right? I mean come on, you have been wrong at least once in your life or maybe you asked a simple question once Mr. Vigne right? Please tell me so. I recon that you have been helpful to some folks but in my humble opinion that does not give you the right to talk down or insult others just because they have different opinions. I do not know much about Audio and by God I am not a Math Wiz but I enjoy a lot of things in life, family first then friends and hobbies (music being the first). You do have some real good close friends right Mr. Salesman?..... No? Just your computer? You live attached to it? Ok well that explains lots of things. My apologies Sr. No, I will not be here when or if you take some of your valuable time to reply to this insignificant post. You are worth one post and one post only. Just in case (because you are so predictable)....no, I am not Wiley. I have been a member for little over two years. I do not post a lot but read with much interest some threads especially when guys like Frank Abela, Art and Stu are involved. Your long posts are quite boring; no way I can read them all, it is difficult to imagine that there is someone other than you on this planet that spends 70% of his life on the internet. |
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New member Username: MagfanPost Number: 1 Registered: Oct-07 | Does max power handling capacity enter in to this thread? I can imaginge 2 speakers with same or similar sensitivity ratings having vastly different power handling limits....and probably different max DB limits, as well. |
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Silver Member Username: GavdawgUpstate, New York Post Number: 953 Registered: Nov-06 | that is along the lines of what Jan is getting at from my understanding. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11444 Registered: May-04 | . Zorro - I'm sorry you find my longer posts boring and lack the attention span required to complete them. The good news for you would be that there are medications you can try in order to alleviate your deficiency. You're not alone in this problem. Even a few forum members have the same affliction. Have you spoken to a physician in an attempt to regain a normal life? If not, I would strongly suggest you consider the possibility. Mind you, I'm not able to give medical advice on this forum. I know audio fairly well and even then I don't pretend to have the ability to diagnose all of the audio problems that are presented here on this forum. So, medical is a bit out of my area of expertise. I just know I have many friends who have struggled with the same ADD problem which would appear to burden your existence and they found their lives turned around once they actively sought help. I can tell you from my experience as a volunteer in the hospital, the effects of ignoring any mental condition can only make the matter worse. Is it posssible this condition has progressed to that point without you recognizing the seriousness of your debilitating disease? You owe it to yourself and your family to get the help that is available. Good luck to you in this. Your family, friends and those with whom you interact on a daily basis should be a great help as they are often the ones who suffer the most when someone around them has physical/mental disorders. It sounds as though you can count on your family to support you as you go through therapy for this sometimes crippling condition. However, I suspect that you, like most of us, have family members who aren't as supportive or really don't give a rat's behind whether you live or die. I have to admit that's how I am with some forum members. I have minimal patience with those newbies who come here looking for a way to screw an audio dealer. I also have very little tolerance for someone who has problems that could be solved by reading their owner's manual. Typically, they are the ones who run through all the gear they've purchased and want us to save them the time of reading the manual by merely instructing them in the proper connection techniques. IMO not understanding is one thing while not wanting to take the time is quite another. With your ADD raging I'm sure you understand the difference. It is the latter group, those just to lazy to do anything to help themself, with whom I have no tolerance. I am particularly disturbed by those who have both screwed a dealer and now want me to help them connect everything. Perhaps you've been in one of those situations also. If so, I'm certain you can understand why this bothers me so. That is if your affliction hasn't got the better of you and you've gone off to read another thread by now. That would be a shame. Someone who can't follow a thought for more than a second. How horrible that must be for you. I am more tolerant but still impatient with anyone who expects me to diagnose and repair their component over the forum. The ones who bother me the most are those who can provide no helpful information because they lack the basic ability to recognize a capacitor/resistor/input/output or they did the damage by doing something incredibly stupid themself. Possibly, you have been in one of those groups and therefore you find me less than helpful. All I can say to that is, I try my best to assist all who come here with good intentions. I do find those who make assumptions about my personal life and habits to be beyond reproach and not worth much of my time. I find those who pay no attention to my side of the debate to possess far more arrogance than I think I have in me. (We all have a bit, eh? Otherwise, we wouldn't be writing on this forum as if we knew what the hell we were talking about.) If you give me no time, what am I expected to give in return? If you pay no attention to what I say, what am I to say in return? I have a bit of a habit of insulting those who have insulted me first and repeatedly. I'm suspect you can understand my reason for that. In your diminished mental capacity I suspect you find people "insulting" you when they are merely asking for more information. However, the ones I find the most loathsome are those who personally insult me and then do a hit and run. To those posters who feel they can say anything, include any insult, and then walk away as if I'm not good enough to give a response to their attack, well, while I'll admit it's a weakness; I can only hope they curl up and die in a very small, damp hole. Not my best trait but should they fall victim to a horrible fate, then be cut up and be fed as chum to a passing shark, it really wouldn't bother me. I suspect I lost you after the first sentence of this post. That's a serious problem you face when you cannot pay attention for more than a few words. It can devastate you social interaction to the point of crippling your interpersonal relationships and make you seem the babbling fool. I wish you the best with this issue and hope that you have found some useful advice in this rather longish post. Finally, why would I suspect you are wiley? You are capable of stringing together more than one sentence at a time. wiley could never do that. . |
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Gold Member Username: Frank_abelaBerkshire UK Post Number: 2397 Registered: Sep-04 | Leo That is definitely part of the equation, and my impression of more sensitive speakers is that their power handling tends to be commensurately lower than that of less sensitive speakers. Furthermore, my understanding is that monitor speakers can reproduce lower frequencies accurately but this has a significant impact on sensitivity. There's maths involved but I don't recall the theory I'm afraid, just that there's a definite link between the the two. The point of this post is that in my view neither Jan nor Peter are completely correct since both of these issues have not been considered in their lengthy 'discussion' for starters. Regards, Frank. |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1039 Registered: Apr-06 | "Furthermore, my understanding is that monitor speakers can reproduce lower frequencies accurately but this has a significant impact on sensitivity. There's maths involved but I don't recall the theory I'm afraid, just that there's a definite link between the the two. " Hoffmans Iron Law, Frank. "That is definitely part of the equation, and my impression of more sensitive speakers is that their power handling tends to be commensurately lower than that of less sensitive speakers." Just depends on the speaker. There are some high sensitivity speakers that have solid power handling characteristics. http://www.klipsch.com/products/details/kpt-mcm-4-t-grand.aspx All depends on what it is designed to do. |
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Gold Member Username: Frank_abelaBerkshire UK Post Number: 2401 Registered: Sep-04 | Stephen, Thanks for that. True about the Klipsch's, but when one looks at all the other brands of sensitive speaker (i.e speakers with sensitivity well into the 90s) their power handling when taken together is generally quite a bit lower than the rest of the market place. Regards, Frank. |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1040 Registered: Apr-06 | All I'm suggesting is that it has more to do with market needs than actual ability to create a sensitive speaker capable of high power handling. Consider a speaker with a true anechoic sensitivity of 100dB, and an impedance of 8 ohms. With 8 watts, it can reach 109dB anechoic at one meter. Translating that to in room at a distance of 10 feet, you get roughly 105dB of output. I don't know about you, but I wouldn't need a speaker capable of significantly higher volumes than that. |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1041 Registered: Apr-06 | And of course there is always Cerwin Vega. |
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Gold Member Username: Frank_abelaBerkshire UK Post Number: 2403 Registered: Sep-04 | Absolutely! It's my understanding that most domestic speakers are designed for a maximum SPL of about 112 db at 1m. This is to avoid possible litigation in some countries should unwise useage result in deafness, but 112db at 1m is approx 108db at 10ft and that's loud! After all, the pain threshold is 116db... |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2082 Registered: Feb-04 | The point of this post is that in my view neither Jan nor Peter are completely correct since both of these issues have not been considered in their lengthy 'discussion' for starters. Hi Frank, My aim was not to include everything that contributes to speaker performance, but rather to exclude as many as possible to examine the relation between two parameters. Sure a parameter such as enclosure volume (to pick one at random) will affect efficiency and sensitivity of the overall loudspeaker, but my point was that both efficiency and sensitivity are affected in the same way. It's basic conservation of energy. If I look at the effect of a storm on surface ocean temperature, I can measure parameters describing the storm and surface temperature without considering other factors that created or affected the storm. |
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Bronze Member Username: 007bPost Number: 17 Registered: Oct-07 | This is absolutely absurd. One poster suggests Vigne has more "leeway" because of the number of his posts containing useful info. Yet he constantly insults other contributors. I guess if I run into the back of the car sitting still in front of me, I should tell the officer I deserve some slack because I have been driving numerous years without incident. Ridiculous. This stuff makes one lose respect for the manner in which the Administrators enforce posting rules. It drives people away. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11446 Registered: May-04 | . If you have not read the entire thread, Frank, I will tell you that I repeatedly mentioned the connection between bass extension and enclosure volume. This is the link you are thinking of. Bass extension, enclosure volume and system sensitivity are interlocked. Change one and you affect the other two. My contention is that speaker systems, unlike raw drivers, have far too many variables to easily tie one specification to another without further information, as in the discussion of bass extension. Even raw drivers, however, have some latitude in how their specifications are obtained. "The point of this post is that in my view neither Jan nor Peter are completely correct since both of these issues have not been considered in their lengthy 'discussion' for starters." I disagree to some extent. This particular issue that you have raised is all about the "speaker systems" which I have said should be considered as different animals than drivers alone. I said that in my first post on this thread. That PG chose to ignore my words and constantly used the term "speaker" to define either or both at his whim seems to have caused quite a bit of the confusion between our arguments and was an issue I strongly objected to on numerous ocassions. I do believe PG had other intentions, however, when he entered into this debate, than to show the error of my words regarding "speakers". You may see it differently and that is your right. Just as long as you also do not ignore my position. PG and I are in disagreement and "incorrect" regarding the other's argument because we are not discussing the same item. He is arguing that a Jaguar automobile has four wheels. I'm arguing that a Jaguar automobile might not be the best choice for towing your boat. His argument is largely that his math is correct. You can read the thread to find where I agree and disagree with that. I have never denied that 88+20 = 108. I have agreeed that physical things obey physical laws. To an extent and then they fail and begin to follow other physical laws. My argument is, partially, that his concept and use of "speaker" is, first, lazy and intellectually tied to a "fantasy land" entity. And, second, that his math does not take into account the realities of a speaker system that requires voltage and current in order to have any sensitivity at all. If you notice, PG's math has no provisions for many of the items and conditions you and I would certainly take into account before recommending a speaker to a client, sensitivity spec not withstanding. That has been my point of debate from the get go. I suggest that "efficiency" is an elusive term that can only be used in the abstract once we assemble any sort of "speaker system". Further, as I have said for years now on this forum, any particular 88dB speaker will not play as loudly for the same "power" input as all other 88dBB speakers and, therefore, "efficiency" is something that really should be considered on a case by case basis. When we are using fantasy land speakers, none of those issues matter. On that point, I agree with PG wholeheartedly. Power handling/sensitivity/efficiency are all interrelated. However, in this case, we are back to no simple formula that can easily tell us if this, then that. There are too many variables to simply and easily tie a 96dB sensitive speaker system to a stated power handling. Power handling is, by its nature, an ephemeral specification that has less real world meaning than sensitivity. I cartainly hope this doesn't spark another heated debate about math. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11447 Registered: May-04 | . "Consider a speaker with a true anechoic sensitivity of 100dB, and an impedance of 8 ohms. With 8 watts, it can reach 109dB anechoic at one meter. Translating that to in room at a distance of 10 feet, you get roughly 105dB of output." SM - I believe your math is wrong here since you seem to interpolate anechoic numbers to in room realities. You ignore room gain in your 105dB number. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11448 Registered: May-04 | . "112db at 1m is approx 108db at 10ft and that's loud!" Each doubling of the distance from the source will result in a dimunition of SPL by approximately -6dB. Room gain not incuded because that would introduce other variables not included in our available information. For example, a dipole radiator will result in a higher in room measurement than a monople. For a given distance, then everything goes to sh!t! . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11449 Registered: May-04 | . "It's my understanding that most domestic speakers are designed for a maximum SPL of about 112 db at 1m." That would be approximately 125% efficiency according to PG's math. . |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1042 Registered: Apr-06 | "SM - I believe your math is wrong here since you seem to interpolate anechoic numbers to in room realities. You ignore room gain in your 105dB number. " I started with the 100dB figure, added 9dB for amplifier gain, 6dB for room gain, and -9.6dB for losses due to distance of 10 feet for a grand total of 105.4, which I rounded to 105. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11452 Registered: May-04 | . "Amplifier gain"? |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1043 Registered: Apr-06 | Going from a 1 watt output to an 8 watt output on the amplifier gains 9dB. *Shrug* |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11453 Registered: May-04 | . Well, okey dokey then! My mistake. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2084 Registered: Feb-04 | That would be approximately 125% efficiency according to PG's math. Give it up. You are continuing to put words in my mouth that I never said. Several people have already asked you to change your ways, yet you continue in your vile remarks. The same ones that you so profoundly object others do on to you. They just make you lose social credibility, so give it up. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11455 Registered: May-04 | . PG, has anyone ever accused you of having a sense of humor? |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2087 Registered: Feb-04 | We would all have a good laugh had we all joked about that earlier. But the joke stems from a misunderstanding between you and me (you never understood why a scientist would use a simplified model to explain concepts), and you have tried to make fun of me about it before. Therefore, it reads to me like the joke is on me. It exactly the type of behavior that you despise from others (and provokes you to excess levels of parody and insults). Please don't dish out what you don't accept for yourself. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11458 Registered: May-04 | . PG - If you had lightened up and had some "positive" dialogue, we might have had a laugh with this thread. As is, you wish to blame me for everything wrong with our exchange. Please, go back and read my remarks about dancing the tango. And go back to read how you entered this thread. Also, let me remind you of the fact that any point I raised was of no interest to you. Any argument I presented was merely dismissed as, how did you put it, yes, you stated you were "not considering non-relevant facts". I said they were relevant but you dismissed them out of hand since they didn't fit your math. All the while insisting that I answer your questions. Do we really need to go through this all again? Yes, Peter, if you increase the "power" 100X, you increase the output by 20dB. In a fantasy amplifier that is connected to a fanatsy speaker that requires no distinction in the term "power". It doesn't even require power since it makes no sound. If you turn your little crank on your fantasy land speaker until the same driver has 20dB more efficiency, you have increased the output by 100%. I agree to all of that. What I don't agree with is the idea that this speaker actually exists. If it doesn't exist, it is of no use to me because it can never make sound. My arguments have been based on a consistent concept that has not varied from the first post I made on this thread. But you refuse you acknowledge any validity to my remarks. Why? I have my own thoughts on that issue but I'll not go into them here since they've been well documented within the thread's content. PG, your addition is perfect. Even my meager math skills tell me that is true. But you have gaping holes in how you got your math to work. Your logic is abstract and contradictory. Your examples are only applicable to a fantasy land where seeking conceptualization, as you put it, leads to alternative realities or none at all, as I put it - many times over. Beyond that I found your entire approach to this thread to be insulting. That you don't see it in yourself is amazing. It's why you showed up here. You are still a hypocrit and a liar regarding wiley. I cannot get past that fact alone. This is also the path our threads together take. Many, many times over. You get p!ssy and stomp off the thread declaring I am too incompetent to understand. As the smoke clears and others come back to survey the damage, you return a day or so later to take yet another swipe at me. I take a few swipes at your arrogance and hypocrisy, this time adding that you are a blatant liar, as you get p!ssier still and finally declare me the worst person in the world and then its done. How many times do we have to repeat this tango before you learn you are the one who is following. I'm quite tired of this, PG. I will debate you on any audio subject at any time. But the results are always the same. You throw out formulas and hold your math over my head while I argue from the trenches that what is on your calcualtor doesn't mean diddly in the real world. The "King" comment really ticked me off this time. That was as low as you have sunk. If you wish to begin this discussion over again - you usually don't - I'll be glad to have another go. But you'll have to play by a few of my rules this time rather than just dismissing them out of hand because they are inconvenient to your math. You decide. As they say in the Westerns, "You know where to find me." One more thing, if you wish to restart this discussion, you'll have to bring a sense of humor even of you have to borrow one. . |
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Silver Member Username: ShawnharmanPost Number: 146 Registered: Dec-05 | Efficiency vs. sensitivity Loudspeaker efficiency is defined as the sound power output divided by the electrical power input. Most loudspeakers are actually very inefficient transducers; about 1% of the electrical energy sent by an amplifier to a typical home loudspeaker is converted to the acoustic energy we can hear. The remainder is converted to heat, typically in the voice coil and magnet assembly. The main reason for this is the difficulty of achieving proper impedance matching between the acoustic impedance of the drive unit and that of the air into which it is radiating. Driver ratings based on the SPL for a given input are known as sensitivity ratings and are notionally similar to efficiency. Sensitivity is usually defined as so many decibels at 1 W electrical input, measured at 1 meter. The voltage used is often 2.83 VRMS, which happens to be 1 watt into an 8 U (nominal) speaker impedance (nominally true for many speaker systems). Measurements taken with this reference are quoted as dB with 2.83 V @ 1 m. The sound pressure output is measured at (or scaled to be equivalent to a measurement taken at) one meter from the loudspeaker and on-axis or directly in front of it under the conditions that the loudspeaker is radiating into an infinitely large space and mounted on an infinite baffle. Clearly then, sensitivity does not correlate precisely with efficiency as it also depends on the directivity of the driver being tested and the acoustic environment in front of the actually deployed loudspeaker. For instance, a cheerleader's horn makes more sound output in the direction it is pointed than the cheerleader could by herself, but the horn does not improve or increase the cheerleader's total sound power output. Typical home loudspeakers have sensitivities of about 85 to 95 dB for 1 W @ 1 m - an efficiency of 0.5-4%. Sound reinforcement and public address loudspeakers have sensitivities of perhaps 95 to 102 dB for 1 W @ 1 m - an efficiency of 4-10%. Rock concert, stadium PA, marine hailing, etc speakers often have higher sensitivities of 103 to 110 dB for 1 W @ 1 m - an efficiency of 10-20%. A driver with a higher maximum power rating cannot necessarily be driven to louder levels than a lower rated one, since sensitivity and power handling are largely independent properties. In the examples which follow, assume for simplicity that the drivers being compared have the same electrical impedance, are operated at the same frequency which is within both driver's respective pass bands, and that power compression and distortion are low. For the first example, a speaker 3 dB more sensitive than another will produce double the sound pressure level (or be 3 dB louder) for the same power input. Thus a 100 W driver ("A") rated at 92 dB for 1 W @ 1 m sensitivity will output twice as much acoustic power as a 200 W driver ("B") rated at 89 dB for 1 W @ 1 m when both are driven with 100 W of input power. For this particular example, when driven at 100 W, speaker A will produce the same SPL, or loudness, speaker B would produce with 200 W input. Thus a 3 dB increase in sensitivity of the speaker means that it will need half the amplifier power to achieve a given SPL; this translates into a smaller, less complex power amplifier and often to reduced overall cost. It is not possible to combine high efficiency, especially at low frequencies, with compact enclosure size, and adequate low frequency response. One can, more or less, only choose two of the three parameters when designing a speaker system. So, for example, if extended low frequency performance and a small box size are important, one must accept low efficiency. This rule of thumb is sometimes called Hoffman's Iron Law |
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Silver Member Username: StryvnPost Number: 526 Registered: Dec-06 | Credit for your source, Shawn? |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2088 Registered: Feb-04 | PG - If you had lightened up and had some "positive" dialogue, we might have had a laugh with this thread. Really think so? Also, let me remind you of the fact that any point I raised was of no interest to you. Any argument I presented was merely dismissed as, how did you put it, yes, you stated you were "not considering non-relevant facts". I said they were relevant but you dismissed them out of hand since they didn't fit your math. All the while insisting that I answer your questions. If we were discussing ocean temperature change off of Maine caused by a storm, and someone insisted that I consider the ocean temperature in the Gulf of Mexico that created the storm, I would say that it's not relevant to the point that I'm trying to make. I could reply without having to worry about that person considering it to be an insult. It wasn't relevant to the simple point that I tried to make several times, but you refused to think about it for a few seconds and see why it wasn't. The questions that I insisted you answer were 30 second thought experiments, while you on the order hand bombarded me with multiple questions you insisted that I answer, otherwise I was evading. Kind of one-sided. What I don't agree with is the idea that this speaker actually exists. You keep repeating this, even now. So the speaker doesn't exist for which the output goes up 20 dB when you raise the input power from 0.01W and turn up the volume 100 times to 1W? Is that your final answer? Beyond that I found your entire approach to this thread to be insulting. That you don't see it in yourself is amazing. It's why you showed up here. You are still a hypocrit and a liar regarding wiley. I couldn't really care less about Wiley per say. I only noticed you were treating someone exactkly the same way you used to treat me. The OP asked about efficiency and he replied with a sensible answer. But you had to cut into him for a technicality. No, I didn't research Wiley's background before posting. I knew yours, and there is was all over again. Cutting in someone over jargon. So I thought it amusing that you didn't see that efficiency and sensitivity are related animals at the same time as you were insulting him for confusing the two terms. you return a day or so later to take yet another swipe at me. I returned to answer Frank. I don't recall taking a swipe at you during it either. You, however, continued and continue to do so. Double standard. I'm quite tired of this, PG. I will debate you on any audio subject at any time. You don't debate. You poke fun at and you name-call. Sure, there's a bit of debating thrown-in, but the recipient has be to very cool-blooded to keep going. Maybe times I answered calmly and thought you would too, only for you to come back even worse, even creating a little storyline to poke fun at me. I suppose you are right proud of that conduct too. he "King" comment really ticked me off this time. That was as low as you have sunk. That's really quite interesting. The King comment was the lowest point that I sunk to. Care to compare it against your barrage of insults? The king comment seems pretty weak in comparison. If you wish to begin this discussion over again - you usually don't Nah. The information is all there. People can read it at their leisure. My repeating it in a different way won't help. But you'll have to play by a few of my rules this time rather than just dismissing them out of hand because they are inconvenient to your math. But then you'll ask me to prove mathematically that changing the speaker impedance or volume enclosure affects the efficiency and sensitivity in the same way. And if somehow I would manage, you'd ask something harder. Instead I tried to start simple and you laughed at me for it, throwing in ivory tower jokes and get help from a student jokes. No thanks. The bar would be set impossibly high and I would to doomed to fail. In fact, you have consistently set the bar higher in an effort to avoid having to agree with anything I said, and keep poking fun at me. I'm the awful scientist yet you are the one who implied headphones were loud enough for a school dance in a gymnasium. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2089 Registered: Feb-04 | I agree with everything in shawnboy's post. But wait for the flaming, because of assume for simplicity that the drivers being compared have the same electrical impedance, are operated at the same frequency which is within both driver's respective pass bands, and that power compression and distortion are low. What? Assumptions to simplify the problem and the discussion? That's not allowed. |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1045 Registered: Apr-06 | Guys, might I make the bold suggestion of a phone call. You can pass a lot more in the way of thoughts and ideas through a phone call with much less in the way of misinterpretation versus a forum post. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11461 Registered: May-04 | . I've made my case and you've made yours. We don't agree on many, many issues. Simple things such as who first brought up the subject of ivory towers and students. I doubt anyone but the two of us care about those matters and I'm quite tired of this BS. If you continue to ignore any comments I make related to the discussion topic and still insist your questions are "thought experiments" you will never move beyond fantasy land speakers that are not driven by an amplifier, make no sound and don't exist. They are, therefore, nothing but fantasies. I've made it clear where I stand on fantasy "speakers" and how they fit into this discussion. You still make no distinction between drivers and speaker systems though that is at the heart of every post I've made on this thread. You still cling to your 20dB. I've agreed 88+20 = 108. I have, however, said it is a meaningless calculation. You won't accept that. You won't accept any conflicting information nor will you address any question I pose. Under those circumstances, there is no debate. I might as well be talking to a brick. Some might say I have been. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11462 Registered: May-04 | . SM- I'm sorry, are you suggesting I make an international call in order to be ignored at my own expense? If after 100+ posts I have not been heard on a single, solitary issue, how do you propose I make a dent? How do I move PG past the idea that fantasy land speakers are not meaningful to anything other than fantasies? That "speaker" means nothing while "drivers" and "speaker systems" are different beasts and things we can discuss? The gulf between us is extremely wide at this point and PG has no oars in the water in order to travel to the other side. . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2091 Registered: Feb-04 | Fantasy land loudspeaker according to JV: The output goes up 20 dB when you raise the input power from 0.01W and turn up the volume 100 times to 1W. |
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Gold Member Username: StefanomVienna, VA United States Post Number: 1047 Registered: Apr-06 | Just throwing out options Jan. I think most people would like you guys to kiss and make up, myself included. You both are reasonable and intelligent gentlemen as far as I can discern. No need for discussions to degenerate this badly. With a phone call, that is less likely to happen, although nothing beats face to face. Perhaps a yahoo chat or something. If you both own mics, you could still do a phone call without the cost. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11463 Registered: May-04 | . shawnboy Posted on Thursday, October 04, 2007 - 07:44 pm: -------------------------------------------------------------------------------- Efficiency vs. sensitivity "Driver ratings based on the SPL for a given input are known as sensitivity ratings and are notionally similar to efficiency." )Notional, adj.: 1) Theoretical, speculative 2) Existing in the mind only, Imaginary 3) Given to foolish or fanciful moods or ideas) "Clearly then, sensitivity does not correlate precisely with efficiency ... For instance, a cheerleader's horn makes more sound output in the direction it is pointed than the cheerleader could by herself, but the horn does not improve or increase the cheerleader's total sound power output." Peter Galbraith Posted on Thursday, October 04, 2007 - 08:25 pm: -------------------------------------------------------------------------------- I agree with everything in shawnboy's post. PG, how can you agree with everything in shawnboy's post and still not agree with any of the points I have made which are virtually identical to shawnboy's post? . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11464 Registered: May-04 | . "Fantasy land loudspeaker according to JV: The output goes up 20 dB when you raise the input power from 0.01W and turn up the volume 100 times to 1W." Please, PG, show me where I posted that? You are back to your lack of comprehension skills; aren't you? Is it medications you lack? Show me the comparison I made to your fantasy land and this 20dB you hang onto as if it proved anything. I've agreed to your 20dB. What more do you want? It has nothing to do with efficiency. It is a red herring but it is your red herring and it is now what you've latched onto to make your case. We've travelled from 108dB being 100% efficiency through 106dB equalling 20% efficiency and 2dB equalling 80% efficiency to now this. None of which is a consistent argument and none of which means anything because most of them are incorrect. You continue to throw numbers around as if they prove something when they prove you can't even do simple math at times. I am at a loss. How do I communicate with a madman? . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2092 Registered: Feb-04 | Using the number pairs from shawnboy's message relating some average sensitivity to efficiency: 85 -> 0.4% 95 -> 4% 103 -> 10% 110 -> 20% We get the black line on this figure:  When we were discussing an average speaker of 88 dB sensitivity and 1% efficiency. I argued that if you didn't change the dispersion of this real-world loudspeaker yet managed to increase its efficiency, the sensitivity increase would follow the blue curve (starting at the bottom with 88 dB at 1%). This is the linear relation between efficiency and sensitivity that I was referring to. Not a bad fit up to 95 dB. This is just conversation of energy. What happens at 95 db? Real-world speakers that operate at 100 dB+ sensitivities don't have the same dispersion pattern as typical 88 dB speakers (they don't use the same type of air-coupling, so the dispersion changes). They therefore increase sensitivity more than would be expected because they concentrate the dispersion pattern. But Peter, didn't you say that 100% efficiency speaker have a sensitivity of 108 dB? Your graph doesn't agree! I said it would if the dispersion pattern were the same as the 88 dB speaker. I also said that wasn't the case. Since we know that typical maximum efficiency values are about 20%, the graph shows that if the dispersion pattern of the 20% effciency loudspeaker were kept exactly the same as the 88 dB loudspeaker, it would have a sensitivity of 101 dB. Horn-loaded speakers concentrate the dispersion some and squeak out up to 110 dB. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2093 Registered: Feb-04 | You continue to throw numbers around as if they prove something when they prove you can't even do simple math at times. Yeah, you're right. What do I know... |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2094 Registered: Feb-04 | Please, PG, show me where I posted that? You are back to your lack of comprehension skills; aren't you? Is it medications you lack? On Wednesday, October 03, 2007 - 04:41 pm, you quoted me: "You have increased output by 20 dB by raising the input volume by 100-fold. It's a perfect speaker without compression. If real-world compression worries you, then imagine we started off at 0.01W or that we only doubled the power. No compression occurred." Then you went on: f you please, from: Jan Vigne Post Number: 11430 Registered: May-04 Posted on Wednesday, October 03, 2007 - 11:40 am: "In the real world most consumer speakers will begin to exhibit dynamic compression at +20dB above baseline sensitivity. The SPL will not go up by 20dB no matter how much you raise the power input. That leaves make believe speakers and large horn loaded systems which are outputting +96dB@2.83 Volts as the only speakers capable of your desired SPL increase."} |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11466 Registered: May-04 | . "But Peter, didn't you say that 100% efficiency speaker have a sensitivity of 108 dB? Your graph doesn't agree!" Good Lord! He's talking to himself! He has almost everthing wrong so he's talking to himself! He is playing his fantasy speakers in his head too, I bet. Is that so he doesn't get any new ideas to deal with? Is that why he's talking to himself? I don't get it. He is mad! He really and truly has gone mad. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11467 Registered: May-04 | . I made the distinction of baseline measurements. We've been through this. This has nothing to do with your 0.01 watts except what your imagine it to. You are in a fantasy! I can't believe it! You are completely nuts! Can't you comprehend anything? What in your mind does this prove? . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2096 Registered: Feb-04 | That's right Mr. Vigne, when having not intelligent to respond, let's try and make fun of the guy. You are so predictable. What's the matter? Can't understand the figure? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11468 Registered: May-04 | . PG - Look at the times on your quotes. How could I have "gone on" if the post which you claim is my further comment was posted before the other?! |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11469 Registered: May-04 | . PG - Just stop for a minute and answer this post. * shawnboy Posted on Thursday, October 04, 2007 - 07:44 pm: -------------------------------------------------------------------------------- Efficiency vs. sensitivity "Driver ratings based on the SPL for a given input are known as sensitivity ratings and are notionally similar to efficiency." (Notional, adj.: 1) Theoretical, speculative 2) Existing in the mind only, Imaginary 3) Given to foolish or fanciful moods or ideas) "Clearly then, sensitivity does not correlate precisely with efficiency ... For instance, a cheerleader's horn makes more sound output in the direction it is pointed than the cheerleader could by herself, but the horn does not improve or increase the cheerleader's total sound power output." Peter Galbraith Posted on Thursday, October 04, 2007 - 08:25 pm: -------------------------------------------------------------------------------- I agree with everything in shawnboy's post. PG, how can you agree with everything in shawnboy's post and still not agree with any of the points I have made which are virtually identical to shawnboy's post? . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2097 Registered: Feb-04 | Can't you comprehend anything? What in your mind does this prove? That compression isn't relevant when you go from 0.01W and increase to 1W. But you didn't understand that simple physics and replied with an irrelevant gabble that concerns starting at 1W and going to 100W. And I'm the ones who's completely nuts? Wow. This is quite a ride. You're funny. You know guys, I'm starting to not mind JV so much now. Kind of like the retarded kid on the block that you don't mind slowing down for once in a while. Oh yeah, that was an insult Mr. Vigne. Consider it payback for the few insults in the last few posts of yours. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2098 Registered: Feb-04 | PG - Just stop for a minute and answer this post. Which part? Let's try the last one in bold okay? "Clearly then, sensitivity does not correlate precisely with efficiency ... For instance, a cheerleader's horn makes more sound output in the direction it is pointed than the cheerleader could by herself, but the horn does not improve or increase the cheerleader's total sound power output." Look at my figure. Where does the correlation breaks down? At 100 dB, when horn-loaded designs make more sound output in the direction it is pointed than the cheerleader could by herself. This is concentrating the dispersion pattern. The horn doesn't increase the total output, it concentrates it into a smaller volume. It's precisely what I was illustrating in my figure. Or did you not get that? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11470 Registered: May-04 | . Peter Galbraith Posted on Thursday, October 04, 2007 - 08:18 pm: JV: If you wish to begin this discussion over again - you usually don't PG: Nah. The information is all there. People can read it at their leisure. My repeating it in a different way won't help. What are we doing now, PG? This is getting spooky. Just how crazy are you? . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2099 Registered: Feb-04 | PG - Look at the times on your quotes. How could I have "gone on" if the post which you claim is my further comment was posted before the other? You paste that quote in yourself after quoting me. Too hard for you to scroll up the page and see? I even provided the time of that post: Wednesday, October 03, 2007 - 04:41 pm |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2100 Registered: Feb-04 | What are we doing now, PG? This is getting spooky. Just how crazy are you? Nice insult! Thanks! I was drawn in with new information, as scientist sometimes are. You could have ignored it. In fact, you did. You just choose to try to ridicule me instead of responding to the real content. Nice going! |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11471 Registered: May-04 | . Your figure is totally absurd. Your argument is totally absurd. You don't really know how a horn works; do you? The quote says, " ... sensitivity does not correlate precisely with efficiency ... ". PG, just what have you been arguing for the last 125 posts? . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11472 Registered: May-04 | . You have the context of those quotes completely out of whack. What you have quoted contains the words "baseline sensitivity". Baseline sensitivity as in the sensitivity at 2.83 Volts. Not at 0.01 watts. We've been through this all before, PG. You didn't seem to have a problem with it then. Are you scouring the posts to try to find a way out of this? . |
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Silver Member Username: Mike3Wylie, Tx USA Post Number: 757 Registered: May-06 | Out of popcorn? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11473 Registered: May-04 | . PG - You have convinced me you are nuts. |
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Silver Member Username: Mike3Wylie, Tx USA Post Number: 758 Registered: May-06 | Seems like the case has been made that one of the main posters here has moved off of his position, about 180 degrees or so depending on whether it was a horn or not. Nice post shawnboy |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11474 Registered: May-04 | . PG - Please answer this question. You've ignored all other questions I've posed to you. You owe me this one. The quote says, " ... sensitivity does not correlate precisely with efficiency ... ". PG, just what have you been arguing for the last 125 posts? Just to remind you, this is from your very first post on this thread: "Frank said: In my view, sensitivity and efficiency go hand in hand. Exactly, ... " Posted on Sunday, September 30, 2007 - 11:43 pm: -------------------------------------------------------------------------------- JV: How? Because there is no direct, consistent connection between raising one and having a specific rise in the other. PG: Quite the opposite, it would be quite hard to raise the efficiency significantly without raising the other. Posted on Sunday, September 30, 2007 - 11:52 pm: -------------------------------------------------------------------------------- JV: And what would the sensitivity of that system be? PG: I haven't worked it out. I suppose it depends on the dispersion angle of that energy, and perhaps to a small degree the density of air (so temperature and humidity). Does that mean that I was wrong? For a given dispersion pattern and air density, I would think that 100% efficiency translates directly to sensitivity. If that's true, then there is more than a little relation between sensitivity and efficiency, don't you think? Someone could read the definition and sensitivity and that of efficiency, notice that they are a bit different and don't even have similar units, and conclude that there things are not related. But a physicist thinks about it for a few seconds to conclude that they must be related. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11475 Registered: May-04 | . Is anyone else paying attention out there? Can someone tell me what is happening? |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2101 Registered: Feb-04 | Yeah JV, it's clear you need all the help you can get! LOL! You are a funny man. Your figure is totally absurd. Thanks for that confirmation. I'm sure it makes all the sense in the world to a physicist and other smart people out there. You have the context of those quotes completely out of whack. What you have quoted contains the words "baseline sensitivity". Baseline sensitivity as in the sensitivity at 2.83 Volts. Not at 0.01 watts. Yeah, strange that you would answer something about compression going from 1W to 100W for the case of 0.01 W to 1W. But you're not that smart, so what more could we expect? |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2102 Registered: Feb-04 | The quote says, " ... sensitivity does not correlate precisely with efficiency ... ". PG, just what have you been arguing for the last 125 posts? Are you really that dense? I have been arguing that that efficiency and sensitivity are linearly related (log scale) when parameters such as dispersion are held constant. That quote says that they don't precisely correlate because of differences in dispersion. The relation is linear if dispersion is held constant, but departs from linearity when it is not held constant. I think my 10 year-old understands more quickly than you do. You really are something to think you are so special and keep missing the mark like that. I'm glad we had this thread. I will never read your posts in the same way again! This thread is priceless to me. You just keep putting your foot in your mouth and you don't even realise that you are doing it! |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11476 Registered: May-04 | . Are you really that comprehension challenged? You'll not read my posts the same way because you've never read them the correct way to begin with. Your ten year old may be doing better than you at comprehension though I suspect there is a flaw in your genetic material. I have never argued that changing dispersion does not change sensitivity. That's a well known and agreed upon fact. Don't make me go back and show you where I agreed. It's at the point where I said controlling dispersion increases the complexity of a speakers system's equation into efficiency. It does so because controlled dispersion does not change the basic efficiency of the driver. The driver's efficiency remains constant as we create a speaker system with the addition of a horn. "For instance, a cheerleader's horn makes more sound output in the direction it is pointed than the cheerleader could by herself, but the horn does not improve or increase the cheerleader's total sound power output." That's what is in that quote! The cheerleader did not get more efficient. In other words, the "driver" did not get more efficient. The cheerleader added a horn to control dispersion thereby making a \i"speaker system"}. My argument has been, from my very first post, that drivers and speaker systems operate under different rules. That fact didn't fit into your attack on me and so you blithely ignored anything I had to say about speaker systems. PG, now you are using my argument and my logic to suggest that is what you've been saying all along! While I'm glad you finally found some logic in this case, you cannot have mine without asking permission. You cannot ignore what I've been saying for 125 posts only to try to use it against me now. If you take a driver and include it in a speaker system of some sort, you have a more complex equation to determine efficiency when starting with sensitivity as a baseline for determining efficiency. Plainly stated for those in ivory towers or mental hospitals, this means looking at the sensitivity spec of a speaker system does not easily tell you the efficiency per centage of the driver. This is from my first post on this thread, "Efficiency and sensitivity are often interchanged and mistakenly used one for the other. They have little to do with each other and should not be used synonyms despite this common practice ..." "Ideally, this efficiency specification should only apply to a raw driver and not to a complete speaker system ... " "Once again this is typically not how "efficiency" is applied." "Sensitivity is a useful term to describe the specified output for a speaker system (or a simple single driver) when a given amount of power is applied to the system or driver's inputs. Therefore, a sensitivity specification should provide the acoustic power (dBw) when either one watt or 2.83 volts are applied to the system. Since speaker systems can vary in impedance and current requirements, the voltage input is preferred over the wattage input in order to more closely reflect the real world conditions of a non-constant impedance load." "Sensitivity specifications are, however, quite liberally quoted and the on paper numbers do not reflect the "difficulty" an amplifier will face when asked to drive any particular speaker system. Low impedance loads are more difficult to drive than high impedance loads. Difficult phase angles are the result of crossovers with high inductance or capacitance and will make life more difficult in most cases for any amplifier. System sensitivity is a very broad number that can be far more misleading than helpful in many cases." Those are the words you objected to in this fashion. This is from your first post on this thread, "Frank said: In my view, sensitivity and efficiency go hand in hand. Exactly, except than Jan Vigne wrote: 'Efficiency and sensitivity are often interchanged and mistakenly used one for the other. They have little to do with each other and should not be used synonyms despite this common practice.' How can they have little to do with each other? How could one double the efficiency and not raise the sensitivity at the same time? If a speaker became 100% efficient, it would have little but to produce a given SPL at 1m at 1W since there is nowhere else for the energy to go." Your simple contention, "How could one double the efficiency and not raise the sensitivity at the same time?" is directly at odds with what I've quoted from my original post. I agreed raising the efficiency of the driver or speaker system will raise the sensitivity when all things remain constant. I disagreed that sensitivity and efficiency are simple equations. I agreed that the addition of controlled dispersion made the speaker system more sensitive. There has never been a disagrement regarding that simple statement. I disagreed with your 4% spec that you pulled out of your @ss to satisfy your math and that equation now has changed to fit pretty much whatever PG needs to make an argument. I did, however, say the addition of the dispersion spec, since it would typically involve the creation of a speaker system, made the equation less simple. You would appear to be using my position as an argument to now prove your position. And you can't have it without first acknowledging that I have held that position from the start. PG: "Since we know that typical maximum efficiency values are about 20%, the graph shows that if the dispersion pattern of the 20% effciency loudspeaker were kept exactly the same as the 88 dB loudspeaker, it would have a sensitivity of 101 dB. Horn-loaded speakers concentrate the dispersion some and squeak out up to 110 dB." That's all well and good but you have to determine other values to arrive at the final efficiency once you change the driver to a speaker system with the addition of a horn of some sort. And, for your information, not all horns operate by controlling the dispersion fron the direct frontal radiation of the driver. That would seem to throw a wrench into your simple math equation. That would make the "efficiency" of a speaker system a more complex equation than a simple driver alone since you now have to determine how the additional rear wave dispersion is handled. Ferchrissake, PG, don't you remember any of this?! Making the equation more complex is my starting point. You have argued against my insistence that speakers operate at no more than approximately 20% efficiency. Remember the 108dB = 100% efficiency? "Going 100-fold more efficient from 1% up to 100% would mean 108 dB sensitivity." Here's something I said early on, "How? Because there is no direct, consistent connection between raising one and having a specific rise in the other." I was talking specifically about speaker systems and sensitivity. Your reply, "Quite the opposite." JV: "What part of "specific" don't you understand, PG?" PG: "I know what specific means. Let me repeat with different words this time around. I believe that one could write an equation relating the efficiency to the sensitivity if the dispersion pattern and air density are known. That, Mr. Vigne, implies a specific one-to-one relation." I agreed that you could write that equation. I argued it wouldn't be that simple. That complexity of equation separates drivers from speaker systems. You cannot deny that has been my position from my very first post. You want to say I cannot be correct by your math, "You read somewhere that Klipschorns had 104 dB sensitivity and 10% efficiency, which doesn't match up what 88 dB and 1%." And then you say you are correct when you use that same baseline, "When we were discussing an average speaker of 88 dB sensitivity and 1% efficiency. I argued that if you didn't change the dispersion of this real-world loudspeaker ... " PG, you have never operated in the real world. You want speakers that exist in a fantasy land. My position has been from the start, real world speaker systems do not have a simple equation that takes sensitivity and manages to turn it into an efficiency spec. All of your mumbojumbo about controlled dispersion only proves that point. Until you do an equation to determine how the horn affects dispersion and then how that number affects sensitivity, you cannot determine efficiency. More complex is more complex. We still have the problem of no simple direct relationship between efficiency and sensitivity when impedance is added to the equation, making it more complex. This becomes even more complex, as was pointed out earlier, when we are discussing drivers and then must calculate for a speaker system. Your controlled dispersion has nothing to do with the efficiency of a driver when the electrical or mechanical impedance is altered. Half the electrical impedance of the driver and you double the power required to produce the same acoustic output. In the real world that makes the driver less efficient for the same sensitivity. When the impedance becomes more complex in a speaker system, the equation becomes more complex and the real world conditions change. None of that matters to you because your equations do not involve the real world. If you would care to sometime step into that real world, PG, I'm sure you'll find it frightening. Take extra meds that day. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11477 Registered: May-04 | . In your make believe fantasy land does the addition of a horn or baffle to control dispersion make for something other than a "driver"? If so, what? Does the addition of the horn or baffle to control dispersion make the calculation for efficiency less simple? If so, how? . |
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Gold Member Username: Frank_abelaBerkshire UK Post Number: 2411 Registered: Sep-04 | Peter The problem with plotting efficiency against sensitivity is that it doesn't make sense. By changing a component in a loudspeaker, you may or may not affect its sensitivity. You may or may not also affect its absolute efficiency but you don't know if or how the change will affect either property until you've measured it. In effect, the change is simply a change and both efficiency and sensitivity may be affected but not necessarily in the same way. That said, if a loudspeaker in an anechoic chamber (the only way to measure output accurately) plays a signal at a level of 90db at a distance of 1m when fed 1 joule of energy for 1 second, and if a component is changed in the loudspeaker such that it subsequently sends out a signal level of 87db, then we can establish that the latter version of the speaker is less sensitive and less efficient than the former version. It's less sensitive than the original because it produces less sound. It's less efficient than the original because the transduction of electrical to mechanical energy consumes more power, thus resulting in the lower sound. However, you can't extrapolate and say if the same speaker was 100% efficient it would be 100-fold as loud. You can't say that because it would be a different loudspeaker subject to completely different rules since no loudspeaker can reach that kind of efficiency rating. In fact, no speaker can come close to 20%. The physics of how they're built and how they work preclude that from being possible (as I understand it). Differences in dispersion are all very well, but under anechoic conditions differences in dispersion count for nothing. Anechoic conditions are generally accepted as the sole acceptable method for measuring loudspeaker performance. Any specifications are anechoic and if not anechoic, then they will usually specify as being 'in-room'. In-room measurements are of limited use since they depend on measuring distance, room dimensions and room construction. Compression is another issue but once again, under anechoic conditions and with the low power signals (1w) being used for measurement compression is not happening anyway. This is why I say that the relationship between sensitivity and efficiency is not as simple as has been made out so far. One has an affect on the other but you can't calculate the effectas simply as a linear log scale since there are other factors at play here, particularly in complete loudspeaker systems with their passive crossover networks causing impedance swings (and power drain) dependant on input frequency and varying phase angles all at the same time. Perhaps we should just let this thread die... Regards, Frank. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11478 Registered: May-04 | . In your make believe fantasy land does the addition of a horn or baffle to control dispersion make for something other than a "driver"? If so, what? Does the addition of the horn or baffle to control dispersion make the calculation for efficiency less simple? If so, how? . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11484 Registered: May-04 | . To anyone still on this merry go 'round; Voltage/current/"power"/impedance/sensitivity/efficiency http://www.stereophile.com/features/99/index2.html Read "Voltage Sensitivity" a short section within what can best be described as a semi-technical article and discover the link between the various factors used to determine "sensitivity" in the real world of loudspeakers that actually make noise. Anyone wishing to then dispute the indirect relationship between the per centage of efficiency and the sensitivity of speaker systems in the real world is welcome to add their two cents. Note to PG: Please, read slowly striving for comprehension. There is no time limit on your work. I understand comprehension is a failing of yours possibly due to genetic flaws or the high altitude of those ivory towers where you reside looking down upon those of us who inhabit the "real world". Or, even the issue of facts not aligning with your preconcieved answer. The math is not difficult but it does directly contradict your assertions which relegate "power" to a "non-relevant" function in the equation. The language of the article is largely real world which, in your case, may require a translator. Try your ten year old son for a start, I suspect he'll understand this better than you despite the shared genetic material. I know you do not do well at comprehension due to your desire to scan for percieved slights and "insults". Resist that temptation just this once, PG. This is an article out of Stereophile magazine and, therefore, has no specific (there's that word again) comments directed at you. The article was written by John Atkinson the highly regarded Technical Editor of both HiFi News and Stereophile. His style is not bent on obfuscation but rather aiming for a middle ground of understanding by those well versed and not so well versed in the audio arts. I'm wondering where you fall in that spectrum, PG, since your understanding of horns, power and so forth is so terribly weak but I hope this one isn't too difficult for you. You might try spending some time in the "real world" for a few minutes before you begin. If that proves too difficult, try upping the meds and waiting for a short time. After you finish the article, please explain how your fantasy land "speakers" deal with the problems outlined in this article. And, please, do not forget the following. In your make believe fantasy land does the addition of a horn or baffle to control dispersion make for something other than a "driver"? If so, what? Does the addition of the horn or baffle to control dispersion make the calculation for efficiency less simple? If so, how? Jan Vigne Posted on Wednesday, October 03, 2007 - 01:03 pm: ------------------------------------------------- PG: "Why would impedance matter if we are using the same speaker, only increasing the power input and output?" JV: Why can't you see you and I are not talking about the same speaker? Jan Vigne Posted on Wednesday, October 03, 2007 - 04:41 pm: PG: "If you double the efficiency (since going close to 100% troubles you so much) without changing anything measurable from the outside of the speaker (impedance, dispersion), what happens to the acoustic output?" JV: It can't be done so why argue that it can or that it proves anything other than fantasy land on paper calculations? PG: "Raising the efficiency raises the sensitivity. Therefore the two are related." JV: Let's get back to basics. You can lower the efficiency of a speaker system by lowering the electrical or mechanical impedance load. You can raise the sensitivity of a speaker system by affecting its dispersion without affecting the efficiency of the raw driver. How does that translate into, "Raising the efficiency raises the sensitivity. Therefore the two are related"? There is no constant there if you make the distinction between driver and speaker system. A point I made on Tuesday, September 18, 2007 - 07:26 pm, when I posted, "Ideally, this efficiency specification should only apply to a raw driver and not to a complete speaker system ... " PG: ""Nevertheless both these characteristics of a loudspeaker system are intimately related. If you manage to have one, you have changed the other." PG: "If you manage to have one, you have changed the other. I meant to write: If you manage to change one (sensitivity/efficiency*), you have changed the other (sensitvity/efficiency*). *JV's addition for comprehension - hopefully. PG: "Not considering non-relevant facts does not make me weaker, nor does it make me an ivory tower professor ... " PG: "Power goes into the speaker and Acoustic power comes out in the air around the whole loudspeaker. This assumption is fairly obvious from all of my examples." PG: "All these things affect both the overall efficiency and sensitivity, which are intimately related." JV: You had me going with you until, " ... which are intimately related." They are but they are unknown variables. That is what I've said, PG, that is what I've said. Speaker systems. Variables. No simple equation. Comprehension skills. Lack of one of the above. PG: "Do you no longer disagree given the context that loudspeaker efficiency and sensitivity refer to the complete package ... ?" PG: "Mr Vigne, I'm very sorry to say that you don't appear to have an ounce of logic in you." . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11485 Registered: May-04 | . PG - I still don't feel you have a good grasp of horn loading. Possibly it would help make your case if you were to provide the "simple" equation for your own Klipschorns as a speaker system. That would involve the equation for the mid and high frequency drivers, both of which are front loaded by expotential compression horns. To my recollection, the rate of compression is not the same for both drivers nor is the flare rate of each expotential horn. Again, as best I can recall, the low frequency driver is both front and back loaded into what amounts to a straight throated horn with no expotential flare. Please, show the math for determining the "sensitivity" gain of each driver as it relates to the specific horn provided for each section of the system. I'm very interested in your calculations for the low frequency driver since its final flare is an unknown which depends on the room dimensions to complete the final fold of the horn and would change with placement along the short or long wall. The combination of both front and back loading of the low frequency system is also of interest to me in this sinple equation. So, don't let me down, eh, PG. . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2103 Registered: Feb-04 | Frank, The problem with plotting efficiency against sensitivity is that it doesn't make sense. You can plot anything versus anything Frank, so see what you get. I got something rather close to my theoretical curve expected with constant dispersion until between 95 and 100 dB. You may or may not also affect its absolute efficiency but you don't know if or how the change will affect either property until you've measured it. In effect, the change is simply a change and both efficiency and sensitivity may be affected but not necessarily in the same way. Why not? Let's see your example... That said, if a loudspeaker in an anechoic chamber (the only way to measure output accurately) plays a signal at a level of 90db at a distance of 1m when fed 1 joule of energy for 1 second, and if a component is changed in the loudspeaker such that it subsequently sends out a signal level of 87db, then we can establish that the latter version of the speaker is less sensitive and less efficient than the former version. It's less sensitive than the original because it produces less sound. It's less efficient than the original because the transduction of electrical to mechanical energy consumes more power, thus resulting in the lower sound. With you so far... However, you can't extrapolate and say if the same speaker was 100% efficient it would be 100-fold as loud. You can't say that because it would be a different loudspeaker subject to completely different rules since no loudspeaker can reach that kind of efficiency rating. In fact, no speaker can come close to 20%. The physics of how they're built and how they work preclude that from being possible (as I understand it). You can draw a line up to 100%. It doesn't mean that you can engineer that speaker. It only tell you how sensitive that speaker would be given the exact same dispersion pattern, if you could build it. As I wrote above, there's no need to get crazy about the extrapolation. If you think you can create a 20% efficient speaker with the same dispersion as the 88 dB sensitivity speaker, then the line tells you it should have a sensitivity of 101 dB. I like your example above. Efficiency is the ratio of acoustic output energy to power input. Sensitivity is the exact same acoustic output spread over a dispersion pattern for a unit of input power. If you modify your loudspeaker and modify its efficiency such that double the energy makes it out, where else is it going to go but spread over the exact same pattern as before and increase sensitivity by the exact same amount. Sure just because sensitivity is related to both efficiency and dispersion does not mean that it is not related to efficiency. It doesn't have to related to a single thing to be related to it, even linearly. It's multi-varied, but from my figure above I'd expect that a lot of the variance in the sensitivity is explained by efficiency alone. Differences in dispersion are all very well, but under anechoic conditions differences in dispersion count for nothing. I disagree. Speaker have different dispersion patterns and they kept them in anechoic chambers. What the anechoic room does is avoid sound bouncing off of wall and room gain. Compression is another issue but once again, under anechoic conditions and with the low power signals (1w) being used for measurement compression is not happening anyway. Right. But now that you mention compression, what do you think happens to both efficiency and sensitivity when compression occurs? Do they both go down? Do they both go down by the same amount? If not, why not? Where is the energy difference going or coming from? This is why I say that the relationship between sensitivity and efficiency is not as simple as has been made out so far. One has an affect on the other but you can't calculate the effect as simply as a linear log scale since there are other factors at play here, particularly in complete loudspeaker systems with their passive crossover networks causing impedance swings (and power drain) dependant on input frequency and varying phase angles all at the same time. So you are saying that impedance swings affect efficiency, likely different at various frequencies. But as the efficiency lowers and goes up again, so does the sensitivity (taking input the also varying dispersion pattern at the various frequencies). That leads to uneven frequency response, so would that be surprising? Efficiency is not as mythical as you guys make it out to be. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2104 Registered: Feb-04 | Some of you appear to get hung-up on that fact that if sensitivity is not ONLY related to efficiency, then it can't be directly related. That's not the general meaning. If someone does a study and says that fuel mileage on your car is directly related to tire under-pressure, would you think he maens that fuel mileage is ONLY affected by that? No, he means when holding other parameters constant. No big deal. |
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Gold Member Username: NuckPost Number: 8837 Registered: Dec-04 | I may have missed it among the high fives and Maitai's, but can I see an iteration of the formula for 'efficiency'? Being a motor, as an assembly, a driver converts electrical energy into mechanical energy. The reference for a motor 's conversion is force X distance over time(no division sign). Some pimple faced kid could figgure it out. Efficiency in this case is proving a bit elusive for me. Clarification? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11486 Registered: May-04 | . "Where is the energy difference going or coming from?" When power compression takes place the energy "difference" as you so uneloquently call it - it's energy loss, OK? - is coming from the voice coil of a driver which is a form of an inductor and has an impedance value. Since inductors resist voltage change, compression takes place. Additionally, in a speaker system power compression takes place due to the numerous capacitors, inductors and resitors used in the crossover filters. Why do you suppose high end speaker designers use air coil inductors? To raise the power input before compression occurs. Very simple to understand. Far less simple to calculate. The more complex the filter, the more difficult it becomes to calculate and the more voltage sensitivity decreases. More complex still because now we've thrown time and frequency into the pot with voltage and current. The impedance changes with increased heat which causes even more complex issues to occur. You do see where I'm going with this I hope. As the number of components increases, the likelyhood the speaker system will suffer power compression increases also. The "power" is converted to heat as the impedance rises and the crossover components and driver voice coils saturate. Plain and simple. Electrical efficiency is lost. Since inductors in particular can be constructed many different ways which will all affect saturation, there is no simple equation to solve this problem either. Capacitors can also be over spec'd for the task to raise the compression point. But you need to calculate all of that. Not an easy task and a bit of what makes speaker design and art and a science. But you wouldn't know anything about either, PG. PG: "Sensitivity is the exact same acoustic output spread over a dispersion pattern for a unit of input power." No, voltage sensitivity is relative to the electrical impedance of the driver or speaker system. Didn't you bother to read the linked article or was it just too tough for you? Why do you refuse to make the distinction between driver and speaker system? They are two distinct items that, if you would make the simple distinction between the two, could move this discussion toward a closing point. PG: "Sure just because sensitivity is related to both efficiency and dispersion does not mean that it is not related to efficiency. It doesn't have to related to a single thing to be related to it, even linearly. It's multi-varied, but from my figure above I'd expect that a lot of the variance in the sensitivity is explained by efficiency alone." That is pure gobbledygook. Are we now dealing in "expectations"? I thought this was solid math which never failed you. You are making stuff up as you go along solely to prolong this thread. You have no facts, you are "expecting" something to pop out of your backside. Admit you are wrong. If it's "multivaried", it's more complex. When are you going to give up, PG? You been shown to be the fool on numerous ocassions. PG: "So you are saying that impedance swings affect efficiency, likely different at various frequencies. But as the efficiency lowers and goes up again, so does the sensitivity>" No, you idiot! When the electrical impedance drops there does not have to be a corresponding decrease in sensitivity. As long as the electrical phase angle remains high, the current draw is minimal and power response remains consistent. That is, this is what occurs in a speaker system with passive filters in line with the drivers. Raw drivers have no electrical phase angle played against impedance other than the self inductance of the voice coil. That makes the efficiency of a raw driver far less complex when calculating from voltage sensitivity. It is what makes the calculation for a speaker system far more complex than that of a raw driver. That is the distinction I made 200 posts ago. Does that now make sense to you? I cannot say it in much simpler terms. A speaker system's electrical efficiency is far more complex to calculate than that of a raw driver. If you agree to that, we're through here. If you continue to pull stuff out of your butt, we'll be here forever. PG: "Efficiency is not as mythical as you guys make it out to be." You are a fool, an incompetent and you are either too lazy to read or too stubborn to comprehend. You have been proven wrong, PG. There is nothing more to make up, nothing more to obfuscate and nothing more to argue. Say you recognize that you have prolonged this thread to 250 posts merely to avoid admitting your errror and your inability to comprehend a single word, "system" as in speaker system. PG: "If someone does a study and says that fuel mileage on your car is directly related to tire under-pressure, would you think he maens that fuel mileage is ONLY affected by that?' Red herring # ... I don't know, I can't keep up. PG: "No, he means when holding other parameters constant. That means it is more complex. Either we get to go home now or you answer my questions. For Pete's sake, PG, admit you are defeated when you are beaten to a bl00dy pulp. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11487 Registered: May-04 | . Read the article, Nuck. http://www.stereophile.com/features/99/index2.html The problem with your type of "efficiency" is there is no transduction to acoustic power taking place in a AC/DC motor. The armature moves and the motor produces horsepower and torque. In a driver the voice coil moves but nothing "happens" until the diaphragm moves againt the mechanical impedance of the the air. This is why JA suggests "efficiency" is a rather bogus spec for a loudspeaker and most particularly for a speaker system. . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2105 Registered: Feb-04 | Now that you mention compression, what do you think happens to both efficiency and sensitivity when compression occurs? Do they both go down? Do they both go down by the same amount? If not, why not? Where is the energy difference going or coming from? Let me clarify the last sentence. If efficiency and sensitivity don't go don't by the same amount, where is the difference in the amounts going or coming from? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11490 Registered: May-04 | . There is no need for clarification, just read my answer to the original. If you believe capacitors, inductors, resistors and voice coils all behave in a simlar fashion to the presence of voltage and current across their terminals, there is no more I can say. All of these items are non-relevant only in fantasy land speaker systems where "speakers" require no "power" in order to not make a sound. They are non-relevant when you refuse to make the distinction I have repeatedly insisted upon and the distinction you have repeatedly and rudely ignored between raw drivers and any sort of speaker system. Compression is still not the topic of this thread. It was introduced to show how far off into fantasy land you've reached and how divorced from reality your "arguments" have become. You can only be interested in power compression if you feel voltage and current are relevant factors in this discussion. If you hold that position, you cannot divorce them from the rest of the facts regarding real world speaker systems. Those facts are in black and white in the Stereophile article and the link I provided long ago regarding the Voltage/Power Paradigm. Read them, PG. Comprehehend what they say outright, not obscured by some illogical gambit to avoid admitting anyone is in error. They hold no position in this fight, they simply present facts on paper. Surely, as an ivory tower inhabitant you value the published word. So which is it, PG? Either you feel voltage and current play a significant role in determining voltage sensitivity or you don't. If you do, my arguments and my linked articles stand as proof you are wrong in your poorly conflated "logic". If you do not, you have admitted the "speakers" you want can only exist in a calcualtor which makes them very different from the speakers I and others have been discussing for the last almost 300 posts. You decide but you cannot have it both ways. Either you have been proven wrong or your argument has no merit in the real world. Now, either give up or answer my questions. Stop asking more of your own until you acknowledge mine. Your continued arrogance in this matter is become overly tiresome. I expect this sort of behavior from a child who doesn't want to admit to wrongdoing. I do not expect this from an adult. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11491 Registered: May-04 | . "If you believe capacitors, inductors, resistors and voice coils all behave in a simlar fashion to the presence of voltage and current across their terminals, there is no more I can say." Since we are now discussing power compression, let me add that gain stages in a power amplifier must be included in that list of components which react to what is presented to them. This is most especially true of any gain stage with feedback applied, which would then include all but a handful of very exotic amplifiers which have other, equally as troublesome, issues. When the speaker system starts to go wonky, since it is in circuit with the amplifier's gain stages and feedback loop and ultimately the amplifier's power supply, the result is the amplifier soon goes wonky too. This can only not happen when "speakers" don't require an amplifier. Do your "speakers" require a power amplifier, PG? Are your "speakers" raw drivers or are they speaker systems? Answer, please. . |
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Silver Member Username: Mike3Wylie, Tx USA Post Number: 784 Registered: May-06 | bump |
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Gold Member Username: NuckPost Number: 8868 Registered: Dec-04 | My amp is quoted as no feedback, but is labelled as zero feedback in balanced connetion, which of course the whole system is. Does this seem relevant? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11497 Registered: May-04 | . Was that feedback or feedforward? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11500 Registered: May-04 | . PG: "I'm glad we had this thread. I will never read your posts in the same way again! This thread is priceless to me. You just keep putting your foot in your mouth and you don't even realise that you are doing it!" |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2108 Registered: Feb-04 | That's right. Keep it coming! |
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Bronze Member Username: 007bPost Number: 26 Registered: Oct-07 | Peter, give it up. You and I both know that you could tell Vigne the world is round but he would die swearing it is flat. Save yourself the aggravation and accept gratitude from those of us who appreciate your knowledge and insight. |
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Gold Member Username: NuckPost Number: 8883 Registered: Dec-04 | accept gratitude from those of us who appreciate your knowledge and insight. I do. In fact, I like reading when smart people talk. Dave Fabrikant had a good quote a while back here, 'If people didn't bicker, it wouldn't be an audio forum". Imagine how boring it would be if we all agreed. Keep it up, kids, and have fun with it. I don't have much to contribute(above my pay grade), but it always fun to watch two eggheads duke it out. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11505 Registered: May-04 | . PG: "That's right. Keep it coming!" Hmmm? Do your own words come back to bite you in your @ss, PG? Luckily for you, no other stuff can be pulled from there as long as they keep gnawing at your backside. Hmmmmmmmmmm? Sounds as if someone is crying Uncle. Or, is that a cry of, "Oh, you mean ol' "King"! You just keep rubbing my face in the fact I'm incapable of even breathing on my own without someone nudging me on a frequent basis." PG, I asked you two very simple questions yesterday just past noon. I've allowed 24 hours for the weekend rush of errands and family time. But, those simple questions require only very simple answers. I would think that if you have time for further insults on other threads, you could easily fit in a few words here. No? OK. To remind you, the questions are: Do your "speakers" require a power amplifier, PG? Yes or no? Are your "speakers" raw drivers or are they speaker systems? One or the other? Answer, please! Silence will be interpreted in the only logical manner left to me. Further obfuscation will be treated likewise. More childish complaints will only make matters worse. PG? . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2111 Registered: Feb-04 | Too much use of whitespace there Mr Vigne. For one thing, you don't get to demand anything around here. Your first question isn't relevant to the elementary physics question at hand, and looked to me like the irrelevant horn-loading questions that you also demanded answers to. You are just waving your hands to distract the casual readers. Your second question was answered so many times it's scary that you need to ask it yet again. Give it up! There's a fundamental relation between efficiency and sensitivity in that they both relate to the ratio of acoustic output to input energy. Anyone with a brain can see that. The sensitivity also depends on dispersion because how much you spread out the output acoustic power will obviously affect its concentration and therefore resultant SPL. It only depends on impedance if we choose the easier-to-measure voltage reference instead of the power reference (which is what we really want). Because sensitivity is related to efficiency AND dispersion, you are arguing that they aren't directly related. But you are standing alone against all of science on that one. Otherwise the only directly related things in this world would be changing units (say the one-to-one relation between Farenheit and Celcius). Not smoking and the incidence of cancer, not atmospheric CO2 and global temperature. You have always missed the point (or never wanted to admit it) that WHEN YOU HOLD DISPERSION CONSTANT, there is a direct relation between efficiency and sensitivity (expressed in dB at 1W at 1m, not volts). There is nowhere else for the energy to go. I even managed to contribute a figure that shows this for typical speaker efficiency and sensitivity values, showing a perfectly straight line with the exact same slope as I predicted. The real-world speaker values only begin to deviate from the CONSTANT-DISPERSION curve for high-output speaker types for which the dispersion is no longer the same. But I'm quite sure that your reply to this will contain a rampage of insults, another series to impossible-to-answer questions, perhaps a little sketch to try to make fun of me, the introduction of irrelevant parameters important to your real-world speakers, etc. But you won't address the point at the beginning of this paragragh. You'll drown your post with other stuff to hide the fact that you don't address it. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11509 Registered: May-04 | . Silence will be interpreted in the only logical manner left to me. Further obfuscation will be treated likewise. More childish complaints will only make matters worse. I cannot and will not endure more from this madman. . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2113 Registered: Feb-04 | That's what I thought. More insults from Mr. Vigne. So predictable. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2114 Registered: Feb-04 | When writing your messages, please use the same courtesy that you would show when speaking face-to-face with someone. Flames, insults, and personal attacks will not be tolerated. It's fine to disagree strongly with opinions, ideas, and facts, but always with respect for the other person. Mr Vigne doesn't follow the rules of the forum one bit. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11512 Registered: May-04 | . Big sigh! You're only sounding even more foolish now, PG. And more desparate. And more childish by twice. As you suggested to me a few hundred posts ago, PG, ... do the math. "I know I'm mad. I've always been mad." Now where have I heard that before? Sorry, PG. You loose. Again! Oh, ... I'm glad we had this thread. I will never read your posts in the same way again! This thread is priceless to me. You just keep putting your foot in your mouth and you don't even realise that you are doing it! Toodles! . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2115 Registered: Feb-04 | King of the forum huh? Amazing. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11516 Registered: May-04 | . PG: WAHHHHHHHHHH!!!!!!! WAHHHHHHHH!!! WAHHHHH! Now you're just looking more like the adolescent sore looser you already appeared to be. PG!!! We played 8 1/2 innings and you came out at least a half dozen runs short. Look, PG, I'm not going to embarrass you any further by insisting I take my last at bat. That wouldn't be fair. Isn't it enough that you lost? I really have no desire to beat the hell out ... Well, I do. But, I'll resist. Just this once. You lost, PG. Again! And again! And again!!! How many times is this that I've kicked your bu++? I know you keep score. I don't. Now, PG, if that appears to be a poor use of white space, adjust your monitor. It's grey on my 'puter. I'm just using the ol' grey matter, PG. I understand if you're having problems with that. Toodles! Again! We've got to stop meeting like this, PG. Didn't I suggest that very thing about two years ago? . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11517 Registered: May-04 | . You lost, PG. . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2119 Registered: Feb-04 | Now you're just looking more like the adolescent sore looser you already appeared to be. Holly crap! And you believe that too, huh? |
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Bronze Member Username: ZorroPost Number: 63 Registered: Jul-05 | Jan: You are wrong my friend, I honestly think that the only loser here is you. You have lost a lot of credibility and respect on this forum, not that you really care but anyway, as I said before you have shown your excessive arrogance and willingness to go to the extreme to try to prove your point and convince everyone that you are always right, how paradoxic, your are a very intelligent man yet you are just a very foolish person. Regards, Z |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11518 Registered: May-04 | . Holy crap! And you believe that too, huh? Look, guys, Im done here. I've proven PG wrong - again - and zorro, like you said, there's no need to respond to people who insult others. You two repeating the same BS - more S than B - ain't gonna change the facts. You're both loosers! And, hey, I'm not going to be checking back for anything since it's all been said and I won. Over and over and over it's been said by PG. It's all been said and I'm right. Again! So you two carry on between the two of you. You seem to deserve each other. But, don't expect any more responses from me. Carry on. Just jabber away. I'm sure no one will care if you two hang around here for awhile. They all stopped reading when I won any way. Don't stay up past your bedtime. Turn out the lights when you're done. Toodles. Yet again. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11519 Registered: May-04 | . Hey, zorro! Kick PG every now and again so he remembers to breathe. Thanks. . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2121 Registered: Feb-04 | Seems JV managed to leave for all of 2 minutes! there's no need to respond to people who insult others. That's rich, considering JV did the bulk of the insulting. Hey, zorro! Kick PG every now and again so he remembers to breathe. Right. Mr. Vigne is the model of good forum conduct. Didn't he just say something about people who insult others? You lost, PG. How many times is this that I've kicked your bu++? You lost, PG. Look, guys, Im done here. I've proven PG wrong - again You're both loosers! I'm sure no one will care if you two hang around here for awhile. They all stopped reading when I won any way. This forum is not about sharing or learning anything new for Mr. Vigne. It's about winning. He doesn't care if he's wrong, so long as he believes that others see him as the winner. Bury the evidence in whitespace and babbling until nobody can find it anymore, and declare yourself the "winner". Shows great character. So now that's he gone, I can repost the figure showing the relation between efficiency and sensitivity along with my explanation if anybody has any difficulty finding it. |
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Bronze Member Username: 007bPost Number: 27 Registered: Oct-07 | He'll be back, just like the zombies. |
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Silver Member Username: Mike3Wylie, Tx USA Post Number: 792 Registered: May-06 | I doubt it, but if Jan did it would be more like; MacArthur / Philippines or Arnold / The Terminator Perhaps trolls are more of the; Ghosts / Poltergeist or zombies / The Return of...  |
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Gold Member Username: NuckPost Number: 8889 Registered: Dec-04 | Milk duds. And a tub of soda pop. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11530 Registered: May-04 | . I thought I told you kids to settle down and turn out the lights! Now quiet down and go to sleep! <click> g'night. . |
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Bronze Member Username: 007bPost Number: 29 Registered: Oct-07 | Told you. |
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New member Username: Josh85Gordon, PA Post Number: 1 Registered: Oct-07 | Never in my years on this planet have I witnessed such immature responses. We have some very persistent and stubborn ppl over in the sat section that make this place a little darker as well. This person obviously is dealing with deeper issues than what this forum brings out in him. It's actually beyond funny and borders sad watching someone who appears to be knowledable destroying his reputation by acting like a 6 year old. Your loooong winded posts are monotonous and just dry in the humor you feel you instill. I have been a silent member here for awhile and can always rely on you Jan, to ALWAYS inject your rude and pompous remarks. My first impression of you when I asked about a receiver was shocking. You had no patience and I quickly became embarrassed, something NOBODY should get when asking a question. If everyone is sooo wrong and you are sooo right ALL of the time why post here? Why waste your precious time on us noobs? Isn't there a club somewhere you can go to smoke your cigar and sniff your brandy wearing a silk robe? Get over yourself. Get a new hobby. One that doesn't involve your never-ending, self righteous replies that do nothing but turn away new members. I can see you have anger issues and this forum may be a release for them, but isn't appropriate. 10,000+ posts isn't impressive to me and doesn't give anyone the power of god you seem to proclaim. I remember members here like Glasswolf and Berny. Classy guys who respected EVERYONE'S opinion, right, wrong or indifferent. You can't handle someone expressing an opinion different than yours Jan. You really can't. Personally I think you need the few members here who stand up to you. You can almost see the gleam in your eye when an argument arises. Demanding dominance and the last word, just to claim victory, again, and again, and again......is very therapeutic for you isn't it? You create the very members you complain about Jan. These members don't join the forum just to disagree with you. They are members, still learning, like you, looking to contribute the best way they can. They just won't be spoon fed the rumor that you are the "king". Which you're not. You have a lot to contribute and can be credited for a great deal, hats off for that. Now learn how to keep your composure when rattled. Savvy? Don't get all bent out of shape again Jan. I'm not "attacking" you so don't feel you have to report me to Brian. (Shrugs shoulders) I'm just yet another member here you shooed away. I'm not commenting on your intelligence or shoe size, merely your forum etiquette. From reading Frank's posts I can see he has a very level headed, unbiased view of the big picture and I can appreciate his words to you. Learn to breathe, seriously it helps, and how to let go. Just let it go Jan. Let....it....go. |
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Silver Member Username: Nickelbut10Post Number: 553 Registered: Jun-07 | I think Jan already let it go. Obviously some people have not. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2125 Registered: Feb-04 | I read the Stereophile link and it doesn't say add anything much to the discussion. I won't waste anyone's time by commenting it point-by-point. I had adressed the issue of using voltage for convenience, instead of power (what we really want). And the text basically agrees with what I was saying; even the electrostatic speaker example is in agreement. Nothing to see here; move along. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11531 Registered: May-04 | . "I'm not 'attacking' you ... " "I read the Stereophile link ... " " ... the text basically agrees with what I was saying ... " Literally ROTFL Great stuff, guys. . . |
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Bronze Member Username: 007bPost Number: 30 Registered: Oct-07 | I hope the Administrators are objectively monitoring these exchanges. Although, as we have seen, they tend to give Jan a free pass while censoring others with whom he disagrees. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11532 Registered: May-04 | . Really LMAO now. |
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Bronze Member Username: 007bPost Number: 31 Registered: Oct-07 | Josh, forgot to mention two things: Vigne will be calling you "Wiley" and watch out for a request to ban you. |
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Gold Member Username: Frank_abelaBerkshire UK Post Number: 2427 Registered: Sep-04 | Baxter, Leave Jan be please. Josh, I appreciate the sentiments, but your language was certainly ... robust to say the least. It certainly reads like an attack. Just glad Jan is being sensible and leaving it be. Regards, Frank. |
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Bronze Member Username: 007bPost Number: 32 Registered: Oct-07 | Frank, while I generally view your posts with an open mind, your advice might be better served on Vigne. Or have you allowed a few flattering entries to cloud your judgement and distort the facts? |
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Bronze Member Username: Josh85Gordon, PA Post Number: 11 Registered: Oct-07 | My apologies Frank, and to you Jan if my post is seen as an attack. I'm not "wiley". I'm simply someone that's been reading silently since my dealings with Jan. At first I thought I broke some unwritten rule and just let it die. I now however see many ppl b4/after me have the same feelings. It's just an observation. I'm a member of various forums and was caught off gaurd in this one is all. It made me feel I did something wrong because I didn't know something. Jan and LK are much the same. (LK over in the sat section). You should see the creatins that pop up over there after LK goes head to head with someone. LK's etiquette is much like Jan's. Then trolls start trashing the forum in protest. It doesn't help anyone and is far more destructive than helpful. I'm not a troll. I'm middle aged with kids who simply opened this thread and thought I'd pull a skeleton out of my closet and get something off my chest. That is all. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2126 Registered: Feb-04 | Then I don't see why you are apologising for anything Josh. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2127 Registered: Feb-04 | Read the article, Nuck. http://www.stereophile.com/features/99/index2.html The problem with your type of "efficiency" is there is no transduction to acoustic power taking place in a AC/DC motor. The armature moves and the motor produces horsepower and torque. In a driver the voice coil moves but nothing "happens" until the diaphragm moves againt the mechanical impedance of the the air. This is why JA suggests "efficiency" is a rather bogus spec for a loudspeaker and most particularly for a speaker system. Did you read the page Nuck? Did you see where the author went into great detail about single driver efficiency versus whole speaker sensitivity that JV alludes to? Did anyone else? The page is about whole system power efficiency (expressed in %) versus the easier to deal-with voltage sensitivity (expressed in dB/2.83V/1m). Not quite the same thing. The voltage versus power distinction is made because amplifiers amplify voltage and not power. The power that is drawn from the amplifier then depends on the impedance of the loudspeaker system at the driven frequency. His extreme example is of a speaker with an impedance of over 100 ohms at low frequency. At any voltage, the high impedance draws little current compared to an 8-ohm system and therefore also draws little power. He argues that the low 79 dB/2.83V/m voltage sensitivity still corresponds to a high power efficiency. Assume the load was 100 ohms and that the power was therefore 0.08 Watt to reach 79 dB at 1m. What is the power sensitivity expressed as dB/1W/1m? About 90 dB/1W/1m. What is the efficiency? We don't know the dispersion pattern but probably around 2%. It's debatable whether the author should call this a very efficient system, but at least it's above average. |
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Gold Member Username: Frank_abelaBerkshire UK Post Number: 2432 Registered: Sep-04 | Baxter, Jan is sensibly not reacting to the taunts, so it seems reasonable and sensible to attempt to stop the taunting which can only otherwise prolong a very distasteful situation. Josh, I appreciate your words enormously. I apologize if I came across too strongly. I did not mean to do so. Regards, Frank. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11536 Registered: May-04 | . Very gracious of you, PG, to accept Josh's apology to Frank and me. |
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Silver Member Username: NoutPost Number: 105 Registered: Mar-06 | Will this thread ever end? Admin, Would you please put a lock on it? |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2128 Registered: Feb-04 | I didn't accept his apology. On the contrary... |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11542 Registered: May-04 | . My point exactly. Isn't this where you came in? Sticking your nose in business that doesn't concern you. What is your problem, PG? . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2129 Registered: Feb-04 | Isn't this where you came in? Sticking your nose in business that doesn't concern you. I came in to add some content in disagreement with the illustrious Mr. Vigne. In your book, that's not allowed. Just as someone should point out how generally rude you can be. That also wasn't allowed and he felt he had to apologize for his misconduct. Not that you would ever do anything wrong to deserve such criticism in the first place. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11545 Registered: May-04 | . PG - You have no problem telling lies and I have no desire to be lied to. I suggested months and months ago that you and I avoid each other on this forum if the conversation could not remain civil. You've proven your worth in this matter. This thread has nothing more to say and I'm not going to sit here and read your lies and insults. Now, you can prove you have some sense by simply letting this thread drop. Or, you can prove you are an immature child by responding and continuing this thread for even one more post. In the future, PG, I suggest you ignore me and I will ignore you. . |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2130 Registered: Feb-04 | Now, you can prove you have some sense by simply letting this thread drop. One would not prove the other. Or, you can prove you are an immature child by responding and continuing this thread for even one more post. I've keep my cool during a great majority of my posts on this thread, ignoring your insults, satires and whitespace trolling. So I'm not going to let you come in at the end to finish the thread pretending that you weren't the immature child of the thread. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 11546 Registered: May-04 | . Last word. . |
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