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New member Username: VarneyBirminghamEngland, UK Post Number: 8 Registered: Sep-04 | ....And what is an 'ohm' when it's at home? I know this sounds like a ridiculously tardy question because I've been swapping speakers and amps for years, but I've always simply matched the position of the impedance switch to the number stated on the speakers. Now I have a set of spkrs which say 4ohm on the back and an amp which is not switchable. It says 6ohms - 16ohms. What does all of this mean? I think it would be useful for me to know what I'm dealing with here. Any help in this area would be appreciated, along with any articles anyone's come across explaining it? Thanks in anticipation, V |
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J. Vigne Unregistered guest | You can find your answer in the posts beginning around July 03 : https://www.ecoustics.com/electronics/forum/home-audio/93944.html |
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New member Username: VarneyBirminghamEngland, UK Post Number: 9 Registered: Sep-04 | Thankyou, J. Vigne. I found the posts concerning 'Ohms' abundant in information - none of which could I understand enough to put into practice, I'm afraid. If I understand correctly, an Ohm is a measure of impedance. Impedance being the sum total of resistance, capacitance and a few other things and resistance is what the equipment offers up against the current. Okay - great - but in practice, how do I use this to match speakers to an amp? Should the speaker impedance be higher than that of the amp, or the other way around? Sorry - I've thought and thought about this and I still don't get it. It gets more confusing the more I think about it. Please help! With thanks, V |
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New member Username: VarneyBirminghamEngland, UK Post Number: 10 Registered: Sep-04 | Okay, I've just found an article, by doing a search, which states: "The load plugged into the amp should never go below the minimum impedance or serious damage may occur to the amplifier." My amp states 6ohms-16ohms. My speakers say 4ohms on the backplate. So this means I've bought the wrong speakers to go with my amp? How come I haven't damaged anything yet? Is this why I cannot get a comfortable listening volume out of it without sending the knob past 12'Oclock? Could I already have ruined everything after using it almost daily since July? Worried now. Urgent help needed! V |
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Silver Member Username: GmanMt. Pleasant, SC Post Number: 621 Registered: Dec-03 | I doubt you have done any damage yet. But you do have the wrong amp for your speakers. There may come a time when a loud transient occurs in the music or you play the music too lod for the system causing either a fuse blow on the amp--or worse, blown drivers (speakers)--most likely the tweeter and/or midrange. It really depends on what your speakers are and what is your amp. Some manufacturers of amps are very conservative and don't want to say that they are 4 ohm capable in case something goes awry. But in general, I would either sell your speakers or amp and buy compatible components. If you have damaged your speakers, you would likely hear a "tizz" sound emanating while playing, caused by a blown tweeter. The damage will generally be caused by the amp "clipping" and causing a driver to blow if the clipping lasts too long. To make sure, call or e-mail the speaker and amp manufacturers. |
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J. Vigne Unregistered guest | "If I understand correctly, an Ohm is a measure of impedance. Impedance being the sum total of resistance, capacitance and a few other things and resistance is what the equipment offers up against the current." Impedance is a measurement tool that is most often applied to speakers to represent the overall effect of the electronic parts (including the speaker drivers) on the load the amplifier works into, or more appropriately against. So impedance is the total of all the capacitors, resistors, inductors and the wiring of the speaker voice coils. The impedance can change substantially if the designer hooks a woofer and tweeter together in series or in parallel. You can't change that design but only be aware of the net result. Reistance, by itself, is defined as the "impedance" to current flow. Resistance is a part of impedance but not the whole. Both are measured in Ohms. Confusing but that's the way it is. "My amp states 6ohms-16ohms. My speakers say 4ohms on the backplate." Because manufacturers do not want to constantly be repairing, under warranty, amps that have been abused, more and more are stating they don't want you to use low impedance speakers with their amps. This doesn't always mean you can't use low impedance speakers with any one amp, it merely means if you reaaly make bad choices on a consistant basis the manufacturer of the amp has an out. If you went through the discussion I directed you to, you would see that an 8 Ohm speaker is not a stable 8 Ohms but can be lower and higher at various points in the frequency band it covers. It is not uncommon for a 4 Ohm speaker to go below 2 Ohms in reality so there is a danger for many amps to not like the load the speaker presents. "So this means I've bought the wrong speakers to go with my amp? How come I haven't damaged anything yet? Is this why I cannot get a comfortable listening volume out of it without sending the knob past 12'Oclock? Could I already have ruined everything after using it almost daily since July?" It doesn't mean you have the wrong combination. If the speakers reach their minimum impedance at 30 Hz and you never put 30 Hz into the speakers your amp won't see that load. If the speakers stay around 4 Ohms for most of the frequency range a good amp can often deal with that load without going belly up. It depends on the amp and speaker combination. Why haven't you damaged your amp? Probably because it can deal with the load your speakers are showing it. The amplifier manufacturer may just be tired of explaining why they aren't going to fix an amp that, in their opinion, was abused. They put a label that says don't do this. If you go ahead and do it then they aren't going to say, "well, you are so stupid you can't read, but you're smart enough to buy our equipment so, you are out of luck; would you like to buy another one of our products to replace the one you blew up?" Well, come to think of it they will say that. If your system has worked for several months you may never experience a problem with the combination. But then again you may decide to do something stupid and then you may have to pick up the tab. It works that way when you do stupid things. You can avoid possible damage by paying attention to signs of distress from the speaker or keeping the amp from overheating. As to why you have to turn the volume control so high, that could be several different situations. It may be the output voltage of the source you are using, the sensitivity of your amp or speakers or the taper design of the volume control itself. If you bought this system from a reputable dealer who should be watching out for you then I would take your questions to them. If you bought this from a Big Box store that just puts stuff on a shelf and sells cheap, well, then, there's your lesson for the day. |
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Bronze Member Username: VarneyBirminghamEngland, UK Post Number: 13 Registered: Sep-04 | J. Vigne ; Gregory - I thank you for your comprehensive help! I read through the posts you directed me to, J. I read, re-read and digested as much as I could. I'm happy to say I'm much more confident with what I'm doing now. So what i've done now is put the NAD in charge of the 4ohm speakers (since it simply switches between 4 & 8ohms) - and hooked up a pair of 6ohm Gale Minis to the 6ohm Cambridge, which states 6ohm. The results are satisfactory and will last now until i can afford some bigger Gales for it. In fact it does seem to be a lot better than with the larger 4ohm floormodels and the peace of mind is now there with it. The dealer is Richer Sounds in Birmingham. I do in fact have confidence in them. I know personally, a few people who have been faced with absolutely no quibbles when wanting to return or refund. So, happy on that score, too - but have decided to stick with the purchase now that I know it's working. Cheers, V |
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Silver Member Username: FryguyNova Scotia Canada Post Number: 256 Registered: Jun-04 | I got a good article to explain it easily that should make it clear about the differences and the formulas to calculate it easily. |
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New member Username: HburnaPost Number: 1 Registered: Oct-04 | hello, i just bought two sets of infinity kappa speakers, two 63.5i 75w rms in the front and two 652.5i 75rms in the back. im not sure what amp i should get for these speakers, i wanna get a good amp that can get the best outta these speakers. what brand and specs do u recommend?75rms x4 at 4ohms amp or 70rms perhaps?would going over the 75rms blow my speakers out? |
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New member Username: HburnaPost Number: 2 Registered: Oct-04 | oops, sorry i posted my question on the home audio instead of car audio. but can anyone make any comments? |
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Silver Member Username: FryguyNova Scotia Canada Post Number: 260 Registered: Jun-04 | Just a 500 watt (peak) 4 channel amp will do you. They push 75 watts RMS into 4 ohm per channel. Pick a brand to your budget. I just got a 500 watt kenwood amp, they all sound the same to me. Speakers are more important then the amp as most now are so good that you can hear any difference anyhow. |
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New member Username: OhmsLondon, Ont. Canada Post Number: 6 Registered: Sep-04 | read your user manuals that come with your equipment or i might be the one reading the service manuals and schematics to fix your equipment if you mismatch the speaker impedance with the capabilities of your receiver.8ohms for 8ohms 4for4 16for16 unless your receiver has the compatible switching capabilities for the impedance for your speakers. |
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Anonymous | whatu do never put a sub that has higher impedance than a amp it could stuff it up if you have protection mode on ur amp then itz fine |
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Silver Member Username: FryguyNova Scotia Canada Post Number: 269 Registered: Jun-04 | Anonymous, dont you mean lower impedance? That will over load the amp if its lower. You can never go too high (within reason), it just under loads the amp and you waste your money because its not pushing the rated power. |