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So we now have a speaker with >5% distortion which isn't audible subjectively. Is a SINAD of 96dB poor?

Prana Ferox

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Isn't the assumption that distortion is additive and you're unavoidably going to spend your"'can't hear it" budget in your signal chain in the speakers, so you want the rest as clean as possible?
 

andreasmaaan

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Look, there's never been any doubt that even great speakers produce orders of magnitude more distortion than good electronics.

But it's important that when people consider/discuss a particular level of distortion, they don't do it in an SPL/frequency/harmonic order vacuum. Distortion audibility thresholds vary wildly depending on:
  • SPL
  • frequency
  • signal
  • harmonic distortion spectrum
50% 2nd harmonic distortion @ 110dB / 40Hz is almost certainly inaudible with any signal.

0.1% 3rd, 4th or 5th harmonic distortion @ 70dB / 1000Hz is likely to be audible with at least some signals.

Masking is more effective at lower frequencies:

1586618097808.png


Masking is more effective at higher SPLs:

1586618154984.png
 

Neddy

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Fascinating thread, and topic I 'sweated' over for a long time - thanks!

BoxEm posted some simple math for how to add the numbers:
https://www.audiosciencereview.com/...rformance-power-amps.10026/page-3#post-366387
Can anyone confirm, or supply a more general equation for calculating overall system SN/DR from the sum of it's components? (Just curious).
(Hm. And end to end set of measurements on a couple different systems by @amirm might be fascinating, eh?)

I had a fairly 'low end' Pre-Pro/HDMI system, and decided to start my upgrades at the source with an OktoDAC, fully expecting that the improvement might be 'muddled' by the still 'less perfect' gear downstream.
That may be the case yet, but the improvements with just the Okto were just astoundingly good - so good a blind A/B test would have been silly.
So I've concluded that significant performance improvements anywhere in the signal chain are worthwhile - (Duh?)
But I'll probably never know if modern TOTL amps (a much smaller 'gain') would provide even more noticeable improvements (cost prohibitive).
 

andreasmaaan

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Can anyone confirm, or supply a more general equation for calculating overall system SN/DR from the sum of it's components? (Just curious).

I think what you're looking for can be found here (with a bonus calculator if you scroll to the bottom of the page).
 

waynel

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@Frank Dernie

Secondly, unlike most electronics, loudspeaker distortion is almost always highly level-dependent. When speakers play softly, they produce less distortion, and when they play loudly, they produce more distortion.

.
this is actually true of most electronics, distortion goes up with level. At low levels noise dominates. As the input or output level increases the distortion increases faster than the signal.
 
OP
Frank Dernie

Frank Dernie

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I have discussed this in several speaker review threads.
So have I and many others, that is why I thought it was worth having it all in one thread, and particularly since nobody has satisfactorily (to me at least) explained why one rule for speakers and a different one for electronics is OK from a SQ pov, I understand making low distortion even frequency response electronics is relatively trivial and getting anywhere near with speakers impossible but that is a practical rather than SQ matter.

It reminds me of a talk I was at many years ago about testing.
It was pointed out that when a new rifle round was proposed millions of tests were commissioned whereas with an intercontinental ballistic missile it would be a handful.
Based on proper testing criteria that implies that the engineers expect the rounds to be very much more potentially unreliable than the ICBM, but we all know why it actually happens, don't we?
 

andreasmaaan

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this is actually true of most electronics, distortion goes up with level. At low levels noise dominates. As the input or output level increases the distortion increases faster than the signal.

I agree, but the point was not that this isn't the case at all with electronics, but rather that the phenomenon tends to be more pronounced with speaker drivers (that's why I used the word "highly").
 

Neddy

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I think what you're looking for can be found here (with a bonus calculator if you scroll to the bottom of the page).
Very nice - thank you!
If correct, this explains a lot?
SN.jpg
 

Neddy

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Ah. Yes. That makes much more sense - thank you!!
 

pma

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What do people think?
My experience tells me the SNR needs to be better than -80dB for it to be inaudible (to me) listening to music and I had accepted the old limit (around for 50 years+) that better than 0.1% distortion (-60dB) was inaudible,

I agree, with a small addition, 0.1% distortion should have decaying profile of the distortion spectrum. That means, the distortion profile should NOT look like the one I am posting and is much more tolerable if it contains only low order harmonics.

The fight for the highest SINAD of electronics is pointless, and 1kHz SINAD, which is nothing but 1kHz THD+N, is as a single number no good measure of the "sound quality".
OPA549 1kHz 6.64V 4ohm.png
 

Ron Texas

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And then there is the Benchmark crowd... Lots of amplifiers from 30 years ago had a SINAD of 65 db and everyone thought they were transparent then. Noise floor is only a problem with low efficiency speakers and desktop setups. My XLS1502 has a SINAS of around 76. Connected to LS50's my ear has to be within 3 or 4 inches of the speaker cone to hear the noise floor, and I get a built in high pass filter to boot.
 

SIY

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I agree, with a small addition, 0.1% distortion should have decaying profile of the distortion spectrum. That means, the distortion profile should NOT look like the one I am posting and is much more tolerable if it contains only low order harmonics.

Just curious, looking at the relatively levels of distortion involved: have you used something like DISTORT to see if you can actually distinguish this in a DBT? I mean, esthetically, if my amp had a distortion spectrum like that, I'd fix it, but I don't honestly know if that's actually audible.

edit: for an actually accurate test, you'd have the distortion drop at lower levels- I see you're at 11W/4R- but the sim would give you a worse case.
 

wwenze

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Say, maybe you're sitting in a perfect location between 2 speakers where the 1kHz cancelled out but the harmonics didn't.

And that you're listening at +60dB above your usual listening levels for some reason.
 

Soniclife

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nobody has satisfactorily (to me at least) explained why one rule for speakers and a different one for electronics is OK from a SQ pov
I don't know if that's true or not, but how about this theory, that I'm not that convinced by.
You have a DAC, amp and speakers that each only generate 2nd and 3rd harmonic distortion. When you feed the signal through the DAC it adds 2nd and 3rd to the input, then the amp adds 2nd and 3rd to it's input, which included the 2nd and 3rd from the DAC, so you now have 2nd, 3rd, 4th 6th and 9th added to the original signal. Now feed that though the speakers and you have 2nd, 3rd, 4th, 6th, 8th, 9th 12th, 16th, 24th and 27th. The levels with be low for the later ones, but the harmonic spray is different from the start point which if audible may be less pleasant than simple 2nd or 3rd, changing to very low distortion DAC or amp cascades the improvements through the chain, giving the speaker less to distort.
 

Hiten

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Can anyone point me to good low distortion speakers. Need to see how they achieved it for learning purpose.
thanks.
addition : by speakers I mean mainly passive speakers.
 

ROOSKIE

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Well the live shows I go to tend to be orchestras and not amplified but with ear bleeding level rock concerts the sound includes the distortion, why should reproduction add more?
I really don't think the only options are orchestral music and ear bleeding rock shows. How about someone playing an acoustic guitar amped so everyone in the room can hear it? That sound is being played through speakers that have characteristics and those characteristics are part of the live show. Yes for making a live album the microphone recording it may be "better" than the speakers used to play for the audience but which is more "real"?
Anyway my point was that in the end if you are not enjoying your process what is the point.
THD is just one type of distortion/coloration. Ever turn the bass up(or down)? That is another distortion/coloration that you might have enjoyed, no different than THD in its ability to change the sound away from the original.
All of this is important, I am not saying it isn't, the reality from my viewpoint is that many products now far exceed our capacity to experience much if any gains by further improvement. This likely varies from ear to ear but surely it is a thing.
 

ROOSKIE

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Look, there's never been any doubt that even great speakers produce orders of magnitude more distortion than good electronics.

But it's important that when people consider/discuss a particular level of distortion, they don't do it in an SPL/frequency/harmonic order vacuum. Distortion audibility thresholds vary wildly depending on:
  • SPL
  • frequency
  • signal
  • harmonic distortion spectrum
50% 2nd harmonic distortion @ 110dB / 40Hz is almost certainly inaudible with any signal.

0.1% 3rd, 4th or 5th harmonic distortion @ 70dB / 1000Hz is likely to be audible with at least some signals.
I agree, certainly my speakers distort far more at certain frequency's and at certain SPL levels, no doubt. The question is what level is audible with music (test tones are for testing and that is great, if I can't hear it with music then I ultimately don't care)
I can not find corroboration that .1% is audible with music at any frequency.
I also can not find much that supports that 3rd order distortion is easy to spot. (@.1% levels) Most of the opions I find suggest 2nd, 3rd are particulaly benign.
Is there any robust speaker distortion testing that has been done that is published and available? Nearly all of what I find is very small studies or dialog on the chat forums. I find some theoretical articles and some very strong guesses but not any real robust stuff (such as Harman's frequency response testing)
 

wwenze

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I don't know if that's true or not, but how about this theory, that I'm not that convinced by.
You have a DAC, amp and speakers that each only generate 2nd and 3rd harmonic distortion. When you feed the signal through the DAC it adds 2nd and 3rd to the input, then the amp adds 2nd and 3rd to it's input, which included the 2nd and 3rd from the DAC, so you now have 2nd, 3rd, 4th 6th and 9th added to the original signal. Now feed that though the speakers and you have 2nd, 3rd, 4th, 6th, 8th, 9th 12th, 16th, 24th and 27th. The levels with be low for the later ones, but the harmonic spray is different from the start point which if audible may be less pleasant than simple 2nd or 3rd, changing to very low distortion DAC or amp cascades the improvements through the chain, giving the speaker less to distort.

The premise is logical. But the levels are so low they would just disappear into the noise floor. Or we can just skip straight to measuring the end result and see that it's dominated by lower harmonics anyway. Here's a something fed by onboard sound.
tkNWurU.png
 

ROOSKIE

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And then there is the Benchmark crowd... Lots of amplifiers from 30 years ago had a SINAD of 65 db and everyone thought they were transparent then. Noise floor is only a problem with low efficiency speakers and desktop setups. My XLS1502 has a SINAS of around 76. Connected to LS50's my ear has to be within 3 or 4 inches of the speaker cone to hear the noise floor, and I get a built in high pass filter to boot.
I mean isn't what you say the point of this site? That a lot of money is being spent of snake oil and audio charms? Man I want to get into some blind tests and see what I really hear.
 
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