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Audibility thresholds of amp and DAC measurements

AresHarvest

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John was, I believe, referring to distortion when listening to music. Two sine waves at 1.5 and 19 kHz isn't comparable, though. Masking plays a huge role when listening to the former, not so with the latter.
 

j_j

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John was, I believe, referring to distortion when listening to music. Two sine waves at 1.5 and 19 kHz isn't comparable, though. Masking plays a huge role when listening to the former, not so with the latter.
Well, it's easy to do distortions that get either IM'ed or aliased down. Do remember that.

And, yes, my example was chosen to be an extremum, and shows why 90dB might not be enough.
 

rwortman

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And yet us oldsters found massive enjoyment listening to our 60db S/N vinyl records and still do. Even when it's easy for a nearly deaf person to hear the difference, the listening experience can still be enjoyable.
 

j_j

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And yet us oldsters found massive enjoyment listening to our 60db S/N vinyl records and still do. Even when it's easy for a nearly deaf person to hear the difference, the listening experience can still be enjoyable.
It all depends on the signal and error spectrum.
 

DonH56

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My great-grandfather found joy using a quill pen and inkwell but happily changed to a ballpoint pen when it was available.

Pretty sure we all, oldsters or not, could come up with a lot of other analogies.

I loved my records and many are still better mastered than the many "remastered" CDs that have the dynamic range squeezed out of them. But warps were annoying, ticks and pops very annoying, and I don't miss the cleaning and setup rituals.
 

Krunok

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Wrong.
My probe signal is a 19khz sine wave.
My noise signal is a 1.5kHz sine wave.

If you play the 19kHz sine wave back at 90dB SPL (assuming your system can do that), at what level can you hear the 1.5kHz sine wave?

You think it's inaudible at 30dB SPL?

Really? No.

You can do the same thing, give or take, with a 40Hz sine wave and a 3kHz sine wave as the 'error' signal.

Once you stick strictly to SNR (ThD, whatever) and don't specify the actual error spectrum, you've really widened the requirements, and yes, then you need to simply stay below absolute threshold of hearing, give or take.
I can't hear 19kHz at all - well, at least for last 10 years. :D

But even when I could I don't really think there was much to hear on a typicall recording of the music I listen to. Maybe your example is a little too extreme? :)
 

Krunok

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Maybe thid graph can serve as an illustration what is ging on in a room (assuming my room is typically noisy):

THD graph vs noise, 85dB @1m:

Capture.JPG


As you can see, although my speakers are not low THD champs their THD (black) is pretty much burried in the ambient noise (brown) for the whole freq range. Btw, this was recorded when there was minimal outdoor noise, usually noise level is 5-10dB higher.

P.S. my guess is that relatively low THD at LF is due to their transmission line design. @Cosmik , there is a chance you would fancy their sound as although they are narrow floorstanders they are also of infinite baffle design. :)
 

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rwortman

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My great-grandfather found joy using a quill pen and inkwell but happily changed to a ballpoint pen when it was available.

Pretty sure we all, oldsters or not, could come up with a lot of other analogies.

I loved my records and many are still better mastered than the many "remastered" CDs that have the dynamic range squeezed out of them. But warps were annoying, ticks and pops very annoying, and I don't miss the cleaning and setup rituals.
I was not suggesting any superiority, just that even high levels of noise and clearly audible distortions don't always make for a horrible listening experience. Indeed, even if one can tell the difference between two DAC's in ABX testing it doesn't follow necessarily that one is subjectively worse sounding than the other.
 

j_j

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I can't hear 19kHz at all - well, at least for last 10 years. :D

But even when I could I don't really think there was much to hear on a typicall recording of the music I listen to. Maybe your example is a little too extreme? :)

The question being answered was "at what point are you SURE you're safe, using only SNR".
 

North_Sky

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Measurements are meaningless if we don't know what is audible and what is not... And yah, there is a bell curve that would apply to most of us :)

Edit - lol obviously I don't know how to multi quote
Edit: To multiquote you first click on the first reply post you want to reply, then scroll back up and click on the second reply of the post you want to reply, scroll back up again and click on the third reply post you want to reply, and keep going till you scroll back up and click on all the posts you want to reply, then all the post quotes will all add up in one post only (yours). Then reply to all of them adding a space line or two between each reply.

It's a little more complex than having a dedicated multiquote icon to click on, but the end result is the same.

* A Multiquote button (small icon @ the bottom right of each post) would be nice.
 
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What do you think about this?
Vanderkooy, J. and Krauel, K.B., 2012, October. Another view of distortion perception. In Audio Engineering Society Convention 133. Audio Engineering Society.
Read the abstract. Especially the last few lines.
 

j_j

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Error spectrum is key to "how much distortion". Let's not forget that.
 

j_j

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Can you please define what you mean by "error spectrum"? Is it the spectrum of the difference caused by distortion or something else?
Well, it's a standard term, it means the difference in spectrum between the "original" and the noisy/distorted/whatever.
 

pkane

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Well, it's a standard term, it means the difference in spectrum between the "original" and the noisy/distorted/whatever.
That makes sense. I have a few different ways to display error spectrum in DeltaWave software, so wanted to be clear (spectrum of error, difference of spectra, phase error, cepstrum, etc.)

What do you think of the distortion df metric that Serge Smirnoff is proposing here?
 

Sergei

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What do you think about this?

Read the abstract. Especially the last few lines.
I found that reading full paper leads to a better understanding. The dominant harmonic in the distortion they studied is 2nd - not in the class of most noticeable. I believe their salient point is that a THD number, out of context, is not overly meaningful.

Their findings are consistent with the findings of others, which help explaining why single-ended triode amps, and "far from conventional" dynamic transducers sound OK to most people, and exciting to some others.
 
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