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Old 2nd November 2009, 08:45 PM   #11
gedlee is offline gedlee  United States
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Originally Posted by PMA View Post
And we are not speaking numbers, but spectra. They are just a part of a whole issue.
It is precisely this issue that should be discussed. Spectra IS a good first step, but there is no standardized approach. Then as you proceed, you will find that the orders for loudspeakers are in general very low and that the orders for electronics can be very high. This means that it's more likely that the electronics will be the source of audible nonlinear distortion than the loudspeaker. Follow on with the fact that some perception issues are not linear in SPL and you have a major complication that makes the viewing of nonlinear distortion in a loudspeaker a relatively unimportant thing. Most people who have studied this problem have come to this conclusion (Toole for one, as noted above). But we all know that loudspeakers DO have audible problems. So what are they if not nonlinearities? This needs to be sorted out far more than anything else.
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Old 2nd November 2009, 08:57 PM   #12
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I would respectfully partly disagree. In some electronics, maybe. In my system I have, at the level shown, all the harmonics are well below -100dB, and only 2nd and 3rd visible. Please tell me, would this be audible? I am sure sometimes we are demonizing order and level of distortion of electronics, especially the well designed for audio purposes. I am sure there is another reason of sonic differences. But I cannot accept, at any level and order, when the amp has higher distortion components than a speaker.
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Old 2nd November 2009, 09:17 PM   #13
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I would respectfully partly disagree. In some electronics, maybe. In my system I have, at the level shown, all the harmonics are well below -100dB, and only 2nd and 3rd visible. Please tell me, would this be audible? I am sure sometimes we are demonizing order and level of distortion of electronics, especially the well designed for audio purposes. I am sure there is another reason of sonic differences. But I cannot accept, at any level and order, when the amp has higher distortion components than a speaker.
It's not the harmonics at high levels that matter its the nonlinearity at very low levels - down into the noise that matters. These are what's audible. If ALL the harmonics all the way out to 10-20th order are 100 dB down when the signal is at the noise floor, then yes, nonlinear distortion in your electronics is not an issue. But then it's also not an issue in the speakers either, so its time to move on to something else.
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Old 2nd November 2009, 09:40 PM   #14
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We both speak low level and do not disagree

Anyway, there are still audible differences, even at low levels and electronics with almost no measurable harmonics. But we are off topic with this here.

My point is that amplifier distortion should not exceed the speaker one, again, at any level and any harmonics order. But, some well accepted amplifiers (by some) do exceed this, even at power level as low as 1W. It is audible.

It was believed that 3% of 2nd harmonic is inaudible. If I add 1% of 2H to 1kHz at about 80dB SPL, I can clearly hear the difference. If it is 3H 1%, I can distinguish it in a blind test at 100% rate. It is not so easy for 2H, but also distinguishable. Not with the amp or speaker with 2% 2H distortion - and this is where the old numbers come from, IMO.
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Old 2nd November 2009, 10:42 PM   #15
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We both speak low level and do not disagree

Anyway, there are still audible differences, even at low levels and electronics with almost no measurable harmonics. But we are off topic with this here.

My point is that amplifier distortion should not exceed the speaker one, again, at any level and any harmonics order. But, some well accepted amplifiers (by some) do exceed this, even at power level as low as 1W. It is audible.

It was believed that 3% of 2nd harmonic is inaudible. If I add 1% of 2H to 1kHz at about 80dB SPL, I can clearly hear the difference. If it is 3H 1%, I can distinguish it in a blind test at 100% rate. It is not so easy for 2H, but also distinguishable. Not with the amp or speaker with 2% 2H distortion - and this is where the old numbers come from, IMO.
Yes, well your numbers certainly disagree with mine, but we are looking at different things. You are talking about thresholds for pure tones, a rather purest test that doesn't correlate with anything found in the real world. I am talking about the levels of THD that are found to be perceptable to annoying for a large group of listeners using music as a source. A far more real world scenario IMO.
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Old 3rd November 2009, 06:08 AM   #16
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Again I think we do not disagree. One singer + one saxophone tolerate high level of low order harmonic distortion, and still accepted well by listeners, even prefered by some. A philharmonic orchestra, well recorded at high dynamics (like Linn SACD Linn Records - Mozart Symphonies 38 - 41 e.g.) does not tolerate high level of distortion and an experienced, trained listener can easily find the difference.
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