you mean to tell me that some here are still using spec's, which too often anymore have little to do with sound quality, in order to qualify means to an end? Ludicrous!
Here's why amps can be more important than speaker
I was looking at B&W's site:
You will notice that speaker total harmonic distortion figures tend to be worse than those of amplifiers and it is reasonable to ask why amplifier designers bother to get down to levels of say 0.01% or lower if the speaker is so much worse. The reason is that most of a speaker's distortion is restricted to the lower-order harmonics, whereas amplifiers can readily generate higher-order harmonics that are much more objectionable.
B&W FAQ
You will notice that speaker total harmonic distortion figures tend to be worse than those of amplifiers and it is reasonable to ask why amplifier designers bother to get down to levels of say 0.01% or lower if the speaker is so much worse. The reason is that most of a speaker's distortion is restricted to the lower-order harmonics, whereas amplifiers can readily generate higher-order harmonics that are much more objectionable.
B&W FAQ
22 responses Add your response
Thank you Sugarbrie for your opinion that i share and one that makes sense. I cannot see how your opinion can be argued. And when it is argued i am unable to understand. Great post. When buying a speaker audition amps. If you have an amp that you will not part with, find a speaker that makes you and your speaker happy. IMO, I don't think there is any other way. Some common sense is needed. You don't buy a 10 watt amp for power hungry speakers. The biggest problem for many is auditioning amps or speakers. This is not always an option. Thats where Audiogon can be so helpful or some of the Audiogon dealers who allow in home auditions. |
Here are some expalantions from Jeff Rowland on amp design: measurements vs. what we hear output stage technology Apparently measurements overlook many audible problems in amp design. |
Hi, If you worry about amp blowing up your speakers, add some fuses for speakers. But in normal condition, it seldom happen unless someone accidentally turn the volume close to max. Human ears can take so much dB, and most of speaker would be too loud for you to bear if you turn the volume too high. A short trasient of bang of music will not generate enough heat/energy to blow speaker in listening level. Someone here also pointed out in Audiogon before: many speakers were blew because receiver's power rating is too low (especially true for transistor amp). A transistor CKT is more likely voltage-limiting. When input signal is too large a sine wave, it will drive output CKT to srong nonlinear region (engineer call it saturation). The result is a sine wave in becomes a square wave out(in voltage). A sharp coner of square voltage wave will create a huge spark of current in inductor load. In this case, speaker is in dangerous of clipping or even blew up. On the hand tube amp is usually more close to current limiting(in this case voltage will overshoot), which is safer to the speaker. But nothing is free(evergy is conservative), energy will burn your power tube not speakers, the result is shorter tube life. I am not encourging people to use 1000W amp on a 30W speakers, but at least give it 30W to make it a fair game when you do comparison. |
That's why some people like over-powered amp than under-powered your amp. The amp will be more in linear region if your power amp is capable of higher current and power than the speaker's demand. If under powered(you can call it bad match), even a good speaker can't perform. If having enough power or up, a good speaker is much better than bad ones. |
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Utter nonsense. A bad speaker sounds bad, period. A cheap amp with a good speaker is far preferable. If you don't think the distortion produced by speakers is troublesome, then you simply don't care what real life sounds like and you have never heard an undistorted speaker. The distortion produced by apseaker does not occur as an ugly noise, but as a coloration - a 50 hz tone is produced as 60 hz, for example. It may not matter to you, but it is everything to me. Speakers and rooms are the real problems nowadays. |
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In the 70s Japanese manufacturers started a spec war offering amps with incredable #s. Most sounded lousy, my trusty 20wpc NAD seeing many more expensive challangers off. Specs dont mean much these days in sound or marketing. You can find plenty of amps or speakers for that matter with similar specs that sound very different. Some speakers require lots of current, some work best with low power tubes. Specs can help make a match, but they dont tell you how stuff sounds. |
Why is it reasonable? Because distortion is cumulative. There's distortion in the recording mike, cables, recording preamp, disc/vinyl mastering, your sources, amps, cables and speakers. It's like asking "why clean your eyeglasses if your windows are dirty?". Speaker distortion a fact of physics life. I second the notion - buy with your ears (and within your credit limit, of course), and not with the back of the brochure. |
In the 70s Japanese manufacturers started a spec war offering amps with incredible #s. Most sounded lousy, my trusty 20wpc NAD seeing many more expensive challangers off. Specs dont mean much these days in sound or marketing. You can find plenty of amps or speakers for that matter with similar specs that sound very different. Some speakers require lots of current, some work best with low power tubes. Specs can help make a match, but they dont tell you how stuff sounds. |
If you drive your amp hard, distortion will be worse than the spec you see on the paper. Those are measured by a constant resistance load, I think, and the signal level they measured are of course at easy power level (which makes numbers looking good). But for real application, amp drives real speakers at pretty high power/current level. The speakers are much tuffer load, depending on frequency and their own distortions are not small even at easy power level. In engineer's words, both are working at nonlinear regions, and those numbers measured at more linear level (lower current and linear load) do not mean much in real life listening. You can use those numbers as reference but should not trust them more than your ears. I would trust those spec's on digital equippments more, those are more linear devices, 0 or 1, and you can't lie about how many bits they are and what sampling frequency is. If they can provide more inf on jittering noise then that would be a good judgement of transport on paper. The only problem is when it gets down to DAC and output state, analog parts come in and the nonlinear effects kick in again. |
Cdc, Don't be so digital! A real sound from the non-electronic/speaker source will also have it's own harmonic distortions. Bringing it down to approach zero means killing a part of life within that. I stopped looking at specs for THD unless it goes above 0.4%. Amp is important in the way that it should be properly engineered and its minimal task is not to destroy speakers at its extreams and normal mode and give them always a nice and pleasant drive. In SS case the heat sinks must be properly matched with transistor parameters, DC offset must be set so that output transistors idle cool(or let's say you can touch them without hurting yourself). In tube amp case more consideration must be taken in PS reliability and proper noise canceling. Proper output protection should take place especially if tube suddenly blows. As to the pricing of the speakers v.s. amps, once the minimal task is in effect it can be either more or less costly. |
No, the reason amp distortion specs are so low is because it's possible, and because a low number looks good on a spec sheet. I suspect most speakers have just as much higher-order harmonic distortion as typical amps do (along wth a lot more lower-order distortion). Most mainstream amps today have harmonic distortion below audibility thresholds; most speakers do not. Amps are important, but this is not why. |