Xmax Question when Designing Box
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Silver Member Username: J_c_wheeler8Columbus, IN United States Post Number: 537 Registered: May-06 | What is the purpose of the xmax spec when designing a box? Isn't Xmax like the excursion of the sub? If so, how come the excursion is a factor when designing the box? I was experimenting boxes for my Type R's and when I typed in 18.2 xmax for them I got like a huge port weaving back and forth using like 4 boards. When i turned the xmax to 16, the box looked normal.. Hmm... |
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Silver Member Username: Waterboy2289Georgia, DiRtY SoUtH ... 2 18 SX w/ ... Post Number: 418 Registered: Jan-06 | That's what happens when you use an el-cheapo calculator like subwoofertools to design your enclosures. |
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Silver Member Username: J_c_wheeler8Columbus, IN United States Post Number: 541 Registered: May-06 | What program would you recommend? Or how else would you determine your frequency manually? Or do you not tune your boxes? |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4753 Registered: Oct-05 | subtools isnt a bad calculator. sure, there are better and more advanced calculators out there but subtools is pretty accurate all around. there are programs such as winISD john (you can google it) |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4754 Registered: Oct-05 | xmax really just represents the distance over which the coil can travel in one direction and maintain a constant number of turns in the gap, or in other words xmax is how far the cone can travel with the coil still in the magnetic gap. So a driver with an xmax of 10 mm can move is cone twice as far as one with an xmax of only 5 mm. alot of people think that xmax is the maximum excursion but, Maximum excursion is how far the cone will travel before 1. the coil hits the back plate or 2. the cone moves so far that it is limited by its suspension. this is why xmax is so important when designing a box, because if you dont enter in the correct amount of xmax of your subwoofer, the sub might over-excur (a word?) and bottom out = BAD |
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Silver Member Username: Waterboy2289Georgia, DiRtY SoUtH ... 2 18 SX w/ ... Post Number: 420 Registered: Jan-06 | WinISD. "Or do you not tune your boxes?" .....That's your thing man. Tune after the build....haha |
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Silver Member Username: ImalikSD2.5ED9.1=Boom, New Jersey Audioque...N... Post Number: 311 Registered: May-06 | John is a good guy...he is asking questions to learn give him a break |
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Silver Member Username: J_c_wheeler8Columbus, IN United States Post Number: 543 Registered: May-06 | THanks bassman, I still cant find some specs for the Type R's Mms bL fLe Cms Dd KLe Xlim Hc Pe Hg Vd Wow that a lot, I looked in the manuel and they didnt have them listed either.. Hmm. Appreciate the support Malik. Matt, your rude and uncontributive comments are most certainly not welcome at this thread, go post your nonsense on one of Kody's threads. |
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Gold Member Username: CenusHicksville, Ohio Post Number: 3148 Registered: Jan-05 | IMO when your building a "normal" box specs really don't matter much, just as long as you have the correst amount of cubic feet, specs like xmax, qts, bl, all that sh1t really only matter when your building a specific box like a t-line, rear horn, bandpass boxes. |
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Silver Member Username: Kaos15thPost Number: 457 Registered: Mar-05 | make a thread for rovin he will tell you what works best he tried different boxes. He uses subwoofertools.com too. |
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Gold Member Username: The_image_dynamicSan Diego Post Number: 1315 Registered: Dec-06 | Good job explaining the difference between xmax and excursion bassman... it is one of the most misunderstood terms in all of audio. |
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Silver Member Username: Waterboy2289Georgia, DiRtY SoUtH ... 2 18 SX w/ ... Post Number: 421 Registered: Jan-06 | I didn't post anything that wasn't true.... |
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Silver Member Username: J_c_wheeler8Columbus, IN United States Post Number: 547 Registered: May-06 | Actually there was nothing that was even close to being factual regarding your statment above. You're just trying to be a pr!ck, and are doing a great job. |
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Silver Member Username: Waterboy2289Georgia, DiRtY SoUtH ... 2 18 SX w/ ... Post Number: 422 Registered: Jan-06 | Haha....I aim to please! |
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New member Username: DevildriverPost Number: 5 Registered: Jun-06 | "xmax really just represents the distance over which the coil can travel in one direction and maintain a constant number of turns in the gap, or in other words xmax is how far the cone can travel with the coil still in the magnetic gap. So a driver with an xmax of 10 mm can move is cone twice as far as one with an xmax of only 5 mm. alot of people think that xmax is the maximum excursion but, Maximum excursion is how far the cone will travel before 1. the coil hits the back plate or 2. the cone moves so far that it is limited by its suspension. this is why xmax is so important when designing a box, because if you dont enter in the correct amount of xmax of your subwoofer, the sub might over-excur (a word?) and bottom out = BAD" Unfortunately, none of that is really the accepted definition of Xmax. Very nice effort in layman's terms, though. Here is a good article on it: http://www.soundsolutionsaudio.com/forum/index.php?showtopic=7113 And how Xmax relates to SPL: http://www.soundsolutionsaudio.com/forum/index.php?showtopic=8375 |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4765 Registered: Oct-05 | well what i said IS what xmax is moron. if i get too technical and wrote it right from the dictionary, then Mr. John Wheeler wouldnt know what im talking about! -- so why would i do somthin like that when wheeler is tryin to understand something in simple terms? ur a dumbazz hxcaudio thanks though brad, its hard to explain xmax, but thats how i think of it when i think of xmax  |
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New member Username: DevildriverPost Number: 7 Registered: Jun-06 | "well what i said IS what xmax is moron. if i get too technical and wrote it right from the dictionary, then Mr. John Wheeler wouldnt know what im talking about! -- so why would i do somthin like that when wheeler is tryin to understand something in simple terms? ur a dumbazz hxcaudio" Well, I was trying to be a gentleman about it, but obviously you are not capable of staying on that level. So with that out of the way, you are simply wrong. You said: "xmax really just represents the distance over which the coil can travel in one direction and maintain a constant number of turns in the gap, or in other words xmax is how far the cone can travel with the coil still in the magnetic gap." In fact, Xmax is neither of those and especially not the second explanation. |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4768 Registered: Oct-05 | actually it is. its another way of saying it, there are many many definitions of xmax... i could of also said that xmax is he amount of LINEAR travel a cone can make while still being controlled by the voice coil. there are many diff. ways of trying to explain xmax, and mine "xmax is how far the cone can travel with the coil still in the magnetic gap" means the same exact thing. look and compare them buddy. |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4769 Registered: Oct-05 | i am also right because (taken from 12volt.com)"Speaker output becomes non-linear when the voice coil begins to leave the magnetic gap" so me saying how far the cone can travel and stay WITHIN THE MAGNETIC GAP is what it means |
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New member Username: DevildriverPost Number: 9 Registered: Jun-06 | "LINEAR travel a cone can make while still being controlled by the voice coil. there are many diff. ways of trying to explain xmax, and mine "xmax is how far the cone can travel with the coil still in the magnetic gap" means the same exact thing. look and compare them buddy." Actually, they do not mean the same thing. BL product quite often drops below 70% of rest value before the coil has left the gap, as shown repeatedly in Dumax and Klippel testing. "i am also right because (taken from 12volt.com)"Speaker output becomes non-linear when the voice coil begins to leave the magnetic gap" so me saying how far the cone can travel and stay WITHIN THE MAGNETIC GAP is what it means" 12volt.com, while a good resource, is not the definitive answer for the topic of Xmax. As the linked article describes: "The definition of Xmax as defined by the Audio Engineering Society as: "The voice-coil peak displacement at which the "linearity" of the motor deviates by 10%. Linearity may be measured by percent distortion of the input current or by percent deviation of displacement versus input current."" It is also worth noting that you have made two different arguments as to what Xmax is: 1) the amount of travel with the same number of turns still in the gap 2) the amount of travel with the coil still in the gap These are two very different arguments. Which of the two do you believe to be the case? |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4770 Registered: Oct-05 | xmax is how far the cone can travel with the coil still in the magnetic gap is the definition in simple terms. wow. if you really wanted me to say
then that would be dumb, because john wheeler or anyone for that matter wouldnt understand that, and say "oh yea, i get it now" your putting percentages and etc into the defintiion, and it doesnt need to be that complicated for someone who is trying to undertstand the basic concept of something. you must not know how a forum works, and how you need to put thing into simple terms so that people would get the basic idea of what it means |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4771 Registered: Oct-05 | and the12volt.com is a very good site. i would rather look at the12volt or bcae1.com than soundsolutions |
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New member Username: DevildriverPost Number: 10 Registered: Jun-06 | "and the12volt.com is a very good site. i would rather look at the12volt or bcae1.com than soundsolutions" The website really has nothing to do with it; it's the source and validity of the information. The article linked to on SSA is much more accurate and thought provoking than what you will find regarding Xmax on the12volt or bcae. |
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Bronze Member Username: DevildriverPost Number: 11 Registered: Jun-06 | "xmax is how far the cone can travel with the coil still in the magnetic gap is the definition in simple terms. wow. " So that's the argument you're sticking to now? Keep in mind that you have mentioned 2 of them now, and this is in fact a less accurate definition than what you originally offered, though sadly, still wrong. Please understand that a driver's motor can be non-linear with the coil still in the gap. Once it is non-linear, Xmax has been exceeded. |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4773 Registered: Oct-05 | exactly, xmax has been exceeded once its been nonlinear.. xmax really just represents the distance over which the coil can travel in one direction and maintain a constant number of turns in the gap or in other words xmax is how far the cone can travel with the coil still in the magnetic gap they mean both the same thing essentially. you want the coil to stay in the magnetic gap or your going to be over-escuring it... so its to the point of which the cone's maximum excursion, with the coil still in that gap... and is also the distance the coil travels, in ONE direction, and maintaning the distance between the gap there is no need to bring percentages in the picture, there is no need for that. you are trying to be wayyyyy to technical. this is plain and simple definition, and it can be found anywhere. from dictionary.com: Xmax: (measured in inches or millimeters) It is the measure of a speaker cone's maximum excursion in one direction while maintaining a linear behavior. The amount of linear travel a cone can make while still being controlled by the voice coil. like i said, these are the simple definitions. no need to get technical with percentages |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4774 Registered: Oct-05 | or you can just not even mention the voice coil,and just state that its the linear (one-way) travel of the cone. |
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Bronze Member Username: DevildriverPost Number: 13 Registered: Jun-06 | "Xmax: (measured in inches or millimeters) It is the measure of a speaker cone's maximum excursion in one direction while maintaining a linear behavior. The amount of linear travel a cone can make while still being controlled by the voice coil." I agree with those definitions 100%. You know why? Because they aren't your definition. Your definition assumes that if the voice coil is in the gap, that is behaving in a linear fashion, which is not always the case. That is the caveat to your definition that I am attempting to explain to you. |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4775 Registered: Oct-05 | your contracdicting yourself because once the voice coil gets out of the linear gap, the sub will over-excur. so you dont want that to happen |
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Bronze Member Username: DevildriverPost Number: 14 Registered: Jun-06 | "your contracdicting yourself because once the voice coil gets out of the linear gap, the sub will over-excur. so you dont want that to happen" No, I am saying that just because the voice coil is in the gap does not mean that it is behaving in a linear fashion. |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4776 Registered: Oct-05 | you worst thing you want to happen is your sub to bottom out and over-excur,which will happen when the coil is not in that certain gap. but thats not saying that the speaker cannot perform when this happens, it still can obviously, but its dangerous for the sub |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4777 Registered: Oct-05 | my definition assumes the sub is performing corretly, and is in linear fashion, because most subs will be performing in linear fashion and thats what you want to be happening |
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Bronze Member Username: DevildriverPost Number: 15 Registered: Jun-06 | "my definition assumes the sub is performing corretly, and is in linear fashion, because most subs will be performing in linear fashion and thats what you want to be happening" That literally made no sense. Again, a sub can behave in a non-linear fashion even if the coil is still in the gap. |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4778 Registered: Oct-05 | in ideal conditions |
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Bronze Member Username: DevildriverPost Number: 16 Registered: Jun-06 | "in ideal conditions" Are you agreeing with me now? |
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New member Username: MrogowskiPost Number: 7 Registered: May-07 | "The voice-coil peak displacement at which the "linearity" of the motor deviates by 10%. Linearity may be measured by percent distortion of the input current or by percent deviation of displacement versus input current."" Yup... This is why it is important to understand and treat Xmax for what it is - just another measurement that *should not* be a deciding factor in choosing a product. I could sell you a sub with an Xmax of 30mm one way, but to achieve that level could result in 80% distortion. This is why I am not caught up in the whole 'Xmax means better' BS... Best, Mark |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4779 Registered: Oct-05 | IT CAN behave in non-linear fashion, but most time IS NOT non-linear. we are talking about different situations, sure it can, but is it good for a sub to be non-linear? of course not, but it still can perform fine... just like clipping a sub, you can be clipping your sub for months and months, is it good for the sub itself? no |
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Bronze Member Username: DevildriverPost Number: 17 Registered: Jun-06 | "IT CAN behave in non-linear fashion, but most time IS NOT non-linear. we are talking about different situations, sure it can," I'm not sure where you're trying to go with this, but if a driver is behaving in a non-linear fashion, Xmax has been exceeded and THIS CAN OCCUR WITH THE VOICE COIL STILL IN THE GAP. Your original definition said that Xmax was the amount the cone can travel with the voice coil still in the gap, which is incorrect because non-linearities are still possible with the voice coil in the gap. "but is it good for a sub to be non-linear? of course not, but it still can perform fine... just like clipping a sub, you can be clipping your sub for months and months, is it good for the sub itself? no" That has nothing to do with the definition of Xmax and is fairly obvious. By the way, there is nothing inherently dangerous or bad about clipping provided you are staying below the maximum thermal power that can be dissipated. Mark, I have to revise that. I re-read that and thought: "hold on, that's only considering the motor" and is therefore not applicable to the definition of Xmax. Looking through the AES paper in which that was stated, that was referring to Xmag only. Good catch. |
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Bronze Member Username: DevildriverPost Number: 18 Registered: Jun-06 | Mark, I should really re-look at that. It seems to be inferring that a deviation in BL product of 10% would be considered Xmag, when in fact a deviation of 30% is the accepted value. The 10% distortion by-product does fall close to the standard that Klippel has been pushing for, though the validity of such a standard is being questioned by the likes of GedLee. |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4780 Registered: Oct-05 | yes, non-linearities ARE POSSIBLE, but in ideal situations the sub will be in linear fashion. my def. is again assuming the sub is linear, which most subs will be performing as |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4781 Registered: Oct-05 | clipping is never good for a sub |
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Bronze Member Username: DevildriverPost Number: 21 Registered: Jun-06 | "yes, non-linearities ARE POSSIBLE, but in ideal situations the sub will be in linear fashion. my def. is again assuming the sub is linear, which most subs will be performing as" Dude, what are you talking about? We are talking about the definition of Xmax and attempting to define when a sub is behaving in a non-linear fashion. If the sub is being non-linear, then it is non-linear whether the coil is in the gap or not, therefore making your original definition inaccurate, as I have argued the whole time. |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4783 Registered: Oct-05 | because you are basically just saying that my def. is wrong because i said in linear fashion.. and your saying that they CAN be in non-linear fashion... yes they can be in non-linear fashion but most of the time will not be. 80% of the time, the sub will be performing in linear fashion although it is possible obviously that i can perform non-linear and still be in the gap! my def. assumes its in linear fashion, yes. if you wanted me to put in that definition that it CAN be non-linear then ok, you won. but most of the time will not be non-linear. |
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New member Username: MrogowskiPost Number: 8 Registered: May-07 | "Mark, I should really re-look at that. It seems to be inferring that a deviation in BL product of 10% would be considered Xmag, when in fact a deviation of 30% is the accepted value. The 10% distortion by-product does fall close to the standard that Klippel has been pushing for, though the validity of such a standard is being questioned by the likes of GedLee." Which makes sense, as the distortion value was used quite extensively many moons ago before DUMAX became a defacto standard. 10% distortion levels in loudspeakers was the norm and was a quantifiable measurement. Best, Mark |
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Silver Member Username: DenimWww.TeamSSAudio.com, MD Post Number: 231 Registered: Nov-06 | It would be best not to argue with Neil on technical matters. Not going to win. |
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Bronze Member Username: DevildriverPost Number: 23 Registered: Jun-06 | Let's not start the clipping conversation. What about clipping damages a driver if it is capable of dissipating the heat? Clipping has a lower crest factor and carries higher average power over time, but if the speaker can safely dissipate this heat, then it does absolutely no damage. Clipping does not damage a speaker, but power does. |
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Gold Member Username: Th3pwn3rPost Number:... Post Number: 2610 Registered: Jul-06 | "Clipping does not damage a speaker, but power does." Yea..thermal power. "Clipping does not damage a speaker, but power does." I think energy would have been a better word in place of power IMO.Anyhow,hXc is right about clipping not causing damage if it can dissipate/handle the heat.That's assuming everything else on the driver can handle wtf ever kind of messed up signal it's attempting to run on.Right or wrong you still win nothing,that goes for both bassman and hXc and the majority of the members here don't even care who's right or wrong besides the two of you guys. |
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Gold Member Username: Dustin3Tigard, OR U.S. Post Number: 4784 Registered: Oct-05 | i guess were special |
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