No. A signal in wrt the signal out. If THD+N is at -120Db asp with a complex multitone, this means that the difference between in and out is bounded by that.
THD+N as a useful metric has been debunked for many decades. Would you like links to scientific references?
Mathematics is not behind this. Physics is behind it. The Mathematics you refer to in this case is for an idealized model of what is really a much more complex physical world. There are three main assumptions we use to justify the approximation that steady state measurements should be reasonably close to reality. Can you name them, or shall I?
Yes, please. I am ready to have a laugh. All papers that I have seen so far that try to debunk objective approaches to audio have so glaring lapses in logic that in the best case they were ludicrous.
You will find that these assumptions are implicit in what I wrote.
Now, physics is expressed through mathematics. Mathematics is the language through which all science is expressed. So, unless you know some laws of physics that are not written in the physics books, but are known only to audiophiles. Of course physics gives us approximate models, not perfect ones, but the way you compute within the corresponding frameworks gives a bound also to the errors. So far, I have seen no proof of what you claim about the audibility, for instance, jitter, or phase of noise of jitter, and so on.
"...This is precisely where the signal-based distortion
metrics fail. In our next paper we will show that .01%
THD of one type of nonlinear system can be
perceived as unacceptable while 10% THD in another
example is perceived as inaudible. Even one of these
simple examples is sufficient to invalidate THD as a
viable metric for discussion of the perception of
distortion. Furthermore, 1% THD is not at all the
same as 1% IM, but we will show that neither
correlates with subjective perception."
http://www.gedlee.com/Papers/Distortion_AES_I.pdf
"The bottom line here is that we know so little about how humans perceive the sound quality of an audio system, and in particular the loudspeaker, that one should question almost everything that we think we know about measuring it. From what we have found most of what is being done in this regard is naive."
http://www.gedlee.com/Papers/Comments on howard.pdf
metrics fail. In our next paper we will show that .01%
THD of one type of nonlinear system can be
perceived as unacceptable while 10% THD in another
example is perceived as inaudible. Even one of these
simple examples is sufficient to invalidate THD as a
viable metric for discussion of the perception of
distortion. Furthermore, 1% THD is not at all the
same as 1% IM, but we will show that neither
correlates with subjective perception."
http://www.gedlee.com/Papers/Distortion_AES_I.pdf
"The bottom line here is that we know so little about how humans perceive the sound quality of an audio system, and in particular the loudspeaker, that one should question almost everything that we think we know about measuring it. From what we have found most of what is being done in this regard is naive."
http://www.gedlee.com/Papers/Comments on howard.pdf
Regarding the Fourier transform: https://dsp.stackexchange.com/quest...urier-transform-good-for-non-linear-processes
Thus we make assumptions that we know make the resulting analysis only an approximation, an estimate. Aside from that typical audio FFT analysis poorly correlates with human perception. We use it as a 'figure of merit' mainly because it is easy to interpret the results.
It follows that burden of proof is on U101222 to prove his claim that steady state HD and or IMD measurement can completely characterize a physical audio device for SQ, contrary to the scientific evidence such as that cited in the post above.
Thus we make assumptions that we know make the resulting analysis only an approximation, an estimate. Aside from that typical audio FFT analysis poorly correlates with human perception. We use it as a 'figure of merit' mainly because it is easy to interpret the results.
It follows that burden of proof is on U101222 to prove his claim that steady state HD and or IMD measurement can completely characterize a physical audio device for SQ, contrary to the scientific evidence such as that cited in the post above.
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AES: "This convention paper has been reproduced from the author's advance manuscript, without editing, corrections, or consideration by the Review Board. The AES takes no responsibility for the contents. ..."
So, not necessarily authoritative. Maybe more of marketing strategy. Distorsion is always distorsion and always unwanted.
//
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So, the above would appear to exactly the type of claim for which U101222 is demanding proof. Two dacs measure equally well, but one sounds bettter than the other!
IIUC U101222 asserts that if both dacs measure down around -120dB, then they must sound the same or the person claiming they sound different must prove it. Mocenigo, is this correct?
Since the discussion was about DACs noise is critical so THD as such is indeed not the best metric which is why THD+N (or SINAD) is the figure of merit for DACs.
"Sounds better" is subjective. I can only guess what sounds good for others. And actually my AK4493 dual dac measures better than Topping E30 so no wonder is sounds better 😉
So you misspoke when you said the measure equally well?
What do they measure anyway, -118dB and -119dB?
Topping E30 II has single-ended output. My dac has balanced output. So not directly comparable.
Yes I did. You can find measurements of Topping E30 II here:
https://www.audiosciencereview.com/forum/index.php?threads/topping-e30-ii-dac-review.36028/
https://www.audiosciencereview.com/forum/index.php?threads/topping-e30-ii-dac-review.36028/