Several monster sized threads about dacs are active at present. Hundreds of opinions about dacs that measure similarly and sound differently there.
Not enough?
Not enough?
I think two identical DACs of same vendor and same type should measure and sound the same.
But there is very little chance of two different DACs (or any audio device) to measure the same. If there are only minor differences, they might sound the same (system resolution dependent, including listening conditions, experience of listeners, etc).
But there is very little chance of two different DACs (or any audio device) to measure the same. If there are only minor differences, they might sound the same (system resolution dependent, including listening conditions, experience of listeners, etc).
I don't want to hijack them. They're not specifically about discussing the subject as a whole, are they?
But if they measure the same down to well below the limit of hearing why would they sound different?
We don't measure everything that can affect the sound of a dac. We use standard measurements that are fairly easy to perform (mostly using a spectrum analyzer), and call it done.
BTW, limits of hearing are not hard limits. They are estimates of an average value for a population. IOW, they are more or less something like the center of a bell curve.
Also, there are two files that measure exactly the same at: https://purifi-audio.com/blog/tech-notes-1/doppler-distortion-vs-imd-7 Do they sound the same to you if using headphones?
BTW, limits of hearing are not hard limits. They are estimates of an average value for a population. IOW, they are more or less something like the center of a bell curve.
Also, there are two files that measure exactly the same at: https://purifi-audio.com/blog/tech-notes-1/doppler-distortion-vs-imd-7 Do they sound the same to you if using headphones?
So what do we not measure that can affect the sound of a DAC?
Limit of human hearing is fairly well studied and we kind of know what level is not audible to most people. Distortions in most DACs fall way, way below that.
Dynamic noise effects that are signal level dependent and that intermodulate with the audio signal. Phase response at low frequencies. Interchannel phase coherence. Etc.
There is also noise that doesn't sound like the kind of noise you would expect. White noise as seen on on a FFT can range from something sounding like resistor hiss, to frying and popping, to one big loud explosive pop.
EDIT: Forgot to mention one ESS once talked about: State variable settling.
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But those things can be measured. Why are you saying we don't measure everything? Amir has noted phase shifts on ASR when reviewing DACs occasionally (note occasionally).
In any case the interchannel phase coherence is shown to be unimportant in this video:
While it is of course possible to make more measurements the real issue is the lack of controls in subjective listening evaluations. Levels are not matched and listening with eyes intead of ears only.
Exactly. Also the fact people are told the expensive one sounds better and conditioned to expect it.
Then the video is wrong. Interchannel phase coherence is a known factor in reproduction of ITD cues.
Here is a theory from Jakob2 which is aimed at explaining the objectivist mindset:
IME this kind of obsession is often to find in people who converted themselves from "golden-ear" to "non-golden-ear" , usually by doing some kind of "blind tests" without knowledge about propper sensory testing.
So they decide having erred all the time when perceiving differences between electronic audio devices (including cables and other stuff) under the premise that the measured numbers are below the known hearing thresholds.
The next step in the reasoning seems to be that they did not just have fooled themselves (when believing these differences exist) but were misled by a world wide conspiracy of manufacturers, reviewers and sales men. This way it is obviously easier to accept the former illusion. "It wasn't my fault, I was tricked into it...."
In this state of belief it is (IMO) apparently extremely difficult to accept informations that provide evidence contrary to the new belief, as it would mean to accept that he might have triple-fooled himself during the conversion process.
https://www.diyaudio.com/community/...designing-yet-another-dac.351495/post-6133569
Jakob2 was probably the most expert sensory researcher in the forum.
In any case, what Howie Hoyt talks about is perfectly consistent with perceptual science:
...for better or worse I have been dragged into hundreds of A/B, ABX/ Random long selection repeats, etc. and in my experience Mark is right, they show excessive negative results, due to lack of training in hearing the difference, as well as the mental confusion of having things switch up. They do show decent correlation for a large number of people for gross differences. Also, IMHO none of these tests do much to eliminate pre-existing biases towards certain SQ contours (the "I'm used to my own speakers" thing).
The only way I have been able to get reliable results and consensus is by weeks of training with specific exaggerated SQ problems (missing bits, odd noise floor contour, mechanical noises on magnetic recordings, etc.) and then reducing them to near-inaudibility. Done this way people train their brains to identify specific sounds. In a similar way we hired and trained pre-press graphics people by placing cards in front of them with small color variations and asked them to pick out the outlier. Some show an ability immediately, but many can learn by repeated testing, resulting in a crew of artists who could pick out microscopic color variations I personally could not see.
https://www.diyaudio.com/community/threads/the-black-hole.349926/post-7310119
In any case, what Howie Hoyt talks about is perfectly consistent with perceptual science:
...for better or worse I have been dragged into hundreds of A/B, ABX/ Random long selection repeats, etc. and in my experience Mark is right, they show excessive negative results, due to lack of training in hearing the difference, as well as the mental confusion of having things switch up. They do show decent correlation for a large number of people for gross differences. Also, IMHO none of these tests do much to eliminate pre-existing biases towards certain SQ contours (the "I'm used to my own speakers" thing).
The only way I have been able to get reliable results and consensus is by weeks of training with specific exaggerated SQ problems (missing bits, odd noise floor contour, mechanical noises on magnetic recordings, etc.) and then reducing them to near-inaudibility. Done this way people train their brains to identify specific sounds. In a similar way we hired and trained pre-press graphics people by placing cards in front of them with small color variations and asked them to pick out the outlier. Some show an ability immediately, but many can learn by repeated testing, resulting in a crew of artists who could pick out microscopic color variations I personally could not see.
https://www.diyaudio.com/community/threads/the-black-hole.349926/post-7310119
Mark you're going to have to explain how two DACs that display very low distortion measurement could sound different to humans. You don't seem capable of doing that and it doesn't make sense that they would.
Someone's opinion of listening tests reads like an excuse. It doesn't bring any new evidence to the party.
Someone's opinion of listening tests reads like an excuse. It doesn't bring any new evidence to the party.
I don't have explain. ESS already did. Some people understand what ESS was talking about, and other people refuse to try to understand before rejecting it. You can't change people's beliefs once those beliefs are very firmly held.
This is what ESS said:
"The surprising reality is that sigma-delta DACs can be audibly distinguished from a conventional DAC despite measuring very much better than that DAC."
"...an important point: The human ear detects signals well below the noise level of the DAC."
"The ear is exquisitely sensitive to "unusual" noise sources. Your ancestors camped out by a waterfall (white noise) and yet their 'ears pricked up" when they heard a hint of a predator moving in the undergrowth. (The equivalent visual phenomenon is "seeing something out of the corner of your eye). Noise, to a large degree, can be accommodated by the ear and is not troubling, but the tiniest "anomalous" noise is raised to the conscious level."
"Sigma-delta modulators create non-periodic steady state noise (non-PSS) artifacts..."
"Periodic Steady State analysis is common in RF circuits. It means that the system is forced to repeat a pattern of behavior over and over again with a certain time period. Any artifact is presumed to also repeat in this time period."
"Audio measurements such as THD and DNR are done in the Periodic Steady State. Therefore, they will not activate non-PSS noise. You will not find non-PSS noise by looking at THD, DNR, and SNR."
"As the audio signal moves, the noise does not remain the same."
"Non-PSS noise is the biggest issue, but experiments suggest there are more problems. For example: Audiophiles rate as inferior systems that have variable excess phase noise."
"We find that an unconditionally stable loop sounds better in listening tests."
There are also some slides with measurements in the presentation at:
https://www.yumpu.com/en/document/read/23182504/noise-shaping-sigma-delta-dacs-ess-technology-inc
"WHY AUDIOPHILES KNOW BY LISTENING IF ITS A SIGMA-DELTA DAC" starts on page 28 of the yompu presentation.
This is what ESS said:
"The surprising reality is that sigma-delta DACs can be audibly distinguished from a conventional DAC despite measuring very much better than that DAC."
"...an important point: The human ear detects signals well below the noise level of the DAC."
"The ear is exquisitely sensitive to "unusual" noise sources. Your ancestors camped out by a waterfall (white noise) and yet their 'ears pricked up" when they heard a hint of a predator moving in the undergrowth. (The equivalent visual phenomenon is "seeing something out of the corner of your eye). Noise, to a large degree, can be accommodated by the ear and is not troubling, but the tiniest "anomalous" noise is raised to the conscious level."
"Sigma-delta modulators create non-periodic steady state noise (non-PSS) artifacts..."
"Periodic Steady State analysis is common in RF circuits. It means that the system is forced to repeat a pattern of behavior over and over again with a certain time period. Any artifact is presumed to also repeat in this time period."
"Audio measurements such as THD and DNR are done in the Periodic Steady State. Therefore, they will not activate non-PSS noise. You will not find non-PSS noise by looking at THD, DNR, and SNR."
"As the audio signal moves, the noise does not remain the same."
"Non-PSS noise is the biggest issue, but experiments suggest there are more problems. For example: Audiophiles rate as inferior systems that have variable excess phase noise."
"We find that an unconditionally stable loop sounds better in listening tests."
There are also some slides with measurements in the presentation at:
https://www.yumpu.com/en/document/read/23182504/noise-shaping-sigma-delta-dacs-ess-technology-inc
"WHY AUDIOPHILES KNOW BY LISTENING IF ITS A SIGMA-DELTA DAC" starts on page 28 of the yompu presentation.
Look at the graphs in the presentation, and learn how DFTs and steady-state distortion tests work. Do you really want to take on that effort to understand the technical part?
Do you have a clue what state variables are in a sigma-delta dac? In not, how could you understand how they make a burst of noise when they settle?
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