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What set of measurements can equate two DACs?

BDWoody

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#21
Consider a device constructed from a low-noise high-Q 1kHz sinusoidal oscillator. The device takes a PCM input which it rectifies and LP filters to well below 1kHz, which is then used to set the amplitude of the generated 1kHz tone. This device would score very well on the DAC SINAD test despite the fact that it's not a DAC at all! You need at least a frequency response test and probably also the IM distortion test to show that a device is even a DAC.
We are clearly simplifying...and the tests done by our host include far more than a simple 1kHz test signal. When multitone, and all the rest of the measurements are included, the device is characterized well enough to make a transparent/non-transparent judgment. At the end of the day, until someone can show that this approach leaves enough on the table for clear and consistently repeatable identification or preference, it seems like it is sufficient, despite all the calls to find what we must be missing.
 
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ebslo

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#22
We are clearly simplifying...and the tests done by our host include far more than a simple 1kHz test signal. When multitone, and all the rest of the measurements are included, the device is characterized well enough to make a transparent/non-transparent judgment. At the end of the day, until someone can show that this approach leaves enough on the table for clear and consistently repeatable identification or preference, it seems like it is sufficient, despite all the calls to find what we must be missing.
Agreed. IMO, the most important measurements for DAC characterization are frequency response and linearity, and of course, the ASR measurements include both. I just wanted to emphasize, in reply to post #13, that neither contribute to SINAD, and that SINAD alone doesn't even prove a device is a DAC at all.
 

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#23
Agreed. IMO, the most important measurements for DAC characterization are frequency response and linearity, and of course, the ASR measurements include both. I just wanted to emphasize, in reply to post #13, that neither contribute to SINAD, and that SINAD alone doesn't even prove a device is a DAC at all.
Why does linearity matter? I.e. what audible characteristic does it translate to?
 
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#27
If two highly rated DAC’s sound different to an individual then it is up to the individual to decide which one they prefer. It is also up to the individual to decide which product offers the most value. Amir’s reviews merely provide you the tools on which to base decisions. There is no reason to introduce more noise in to this process by developing more things to measure.

As a manufacturer of audio components, including DAC’s, are you interested in this topic so you can improve your designs?
 

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#29
@musicapristina , 1kHz SINAD is a very very incomplete rating of a DAC. So, same SINAD does not equate to same behavior.
But, and that is the important point, once SINAD is good enough (say < -100dB), there are little chances that there are any audible differences, assuming all other basic specs (frequency response, etc) are also good enough.
 

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#32
Different aspects of the same thing. Sometimes one view is more revealing than the other.
Could you possibly provide a more generic answer?
I’m not buying it. DAC linearity sounds like something measurable but not necessarily consequential.
 

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#33
Linearity can show, for example, compression effects even when distortion is 100% clean (at least at 1kHz).
Can you give an example of a modern DAC that has above average harmonic distortion measurements and also suffers from audible linearity issues, such as what you’re describing?
 

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#34
Linearity measures output level vs input level over that whole range of levels. Ususally, to not get spoiled by noise or hum, the level is measured band-passed so only the level at the test frequency is measured.
 

KSTR

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#35
I said nothing about audibility, and that has not been your initial question. And your post, quoting me, has no context to what I said. Your ususal game playing as we know it, but no, I'm not going to engage.
 

solderdude

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#36
What set of measurements can be performed on 2 DACs such that if the two sets of measurements were identical,
I have not seen any DAC measure the same in all aspects. They all differ. The question is audibility levels from certain aspects.

This is where I want to get to, though:
If we have 2 "validated transparent" DACs, one selling for $299 and one for $29,999, is it fair to make the claim, based on science, that the $29,999 is over-priced snake oil that sounds the same as the one for $299?
Pride of ownership, used components, looks, usability, functionality, reliability, longevity, balanced/SE out, technical performance, format support.
For some that may be worth to pay more for. In a blind test they could not be told apart but 99.9% of owners does not do blind tests and believes the expensive one sounds better and so it will. Even if placebo to them it's worth it.
To others some or all mentioned aspects are moot, they only care about price/perf ratio and technical sufficient performance.

Is it true that given 2 DACs have equal Noise and Distortion measurements, we can predict that they are indistinguishable in an ABX test?
No, and nobody claims this either.

If NO, then we're applying science in a way that is interesting, but inaccurate, unfair and maybe dangerous.
Also no. We can measure and compare results, We can make measurements of known important aspects and apply known audibility thresholds to make an educated guess about expected performance. Not unfair, not dangerous. Easily misinterpreted by folks that don't understand measurements... definitely !

One needs to measure and correctly interpret all the measurements and know about audibility levels and when they are applicable (under which circumstances)
 

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#37
Linearity measures output level vs input level over that whole range of levels. Ususally, to not get spoiled by noise or hum, the level is measured band-passed so only the level at the test frequency is measured.
Thank you. I did not ask about how linearity is measured, but I’m sure someone else would like to know.

I said nothing about audibility, and that has not been your initial question. And your post, quoting me, has no context to what I said. Your ususal game playing as we know it, but no, I'm not going to engage.
I’m so sorry that it wasn’t apparent to you that since this thread was about DAC measurements and which ones can be used to confirm the absence of AUDIBLE differences, that a logical follow up question would involve providing an example of a DAC that exhibits the audible linearity artifacts that you claim can be heard even without audible THD.
By the content of your response, I think it’s pretty clear that you don’t know.
 

ebslo

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#38
Why does linearity matter? I.e. what audible characteristic does it translate to?
Audible manifestation will depend entirely on the nature of the non-linearity.
We can measure harmonic distortion directly. So why do we care about linearity?
Maybe it's just a difference of perspective, but I consider linearity to be the more direct measurement. It's literally the mapping from input value to output voltage, which is the primary function of a DAC. That said, the distortion measurement is still important as not all distortion can be attributed to non-linearity.
Can you give an example of a modern DAC that has above average harmonic distortion measurements and also suffers from audible linearity issues, such as what you’re describing?
I would hope examples would be rare or nonexistent because any competent DAC should have good linearity. But that's why we want them tested, right? To determine if a particular DAC is indeed competent.
 

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