The present discussion is about fidelity, not what someone thinks, or thinks someone else thinks they might like the sound of, I hope you see the difference.
Of course I do. Problem is that not everything shows up with standard AP tests as significant. Allo thread recently described finding RF noise on I2S lines that affected sound quality audibly, but showed only very slight change in THD. No way for someone to know the very slight change in stationary THD is related to an audible problem without listening. Unless, of course, you have a new measurement for us to use to quantify whether there is an audible problem due to RF noise or not.
EDIT: Of course there is a also a problem being asked to provide evidence of an audible problem in cases where an AP does not show the real magnitude of the problem. The only evidence would be blind listening tests, for which we have no standard protocols everyone will accept. Its like this: I can post an AP printout and nobody suggests that it was faked, but if I report blind testing results people will believe or reject the results depending on which side of the hearing/not-hearing arguments they have already taken a side on.
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So how do you set up such listening procedure? You've been hiding this for a long time. How about sharing that now?
Listening is the core issue in audio. You keep avoiding it for some reason. Must be your agenda which we all know.
Which thread? I feel an itch about what's in... A digital signal affected by RF noise, while the measurements don't show a thing. Are you aware that we can measure the effect of, and discriminate from, noise a useful signal that has a power of 10^-34 W?
Allo posts starting at about: https://www.diyaudio.com/forums/ven...i-dual-lps-5v-3a-5v-1-5a-137.html#post6214729 ...also some more in the next few posts down from that one. Somewhere around that page in the thread Cdsgames metioned the RF they found was getting into the I2S lines before going into the dac chip.
EDIT: Here we go for the I2S lines comment: https://www.diyaudio.com/forums/ven...i-dual-lps-5v-3a-5v-1-5a-133.html#post6210711
EDIT: Here we go for the I2S lines comment: https://www.diyaudio.com/forums/ven...i-dual-lps-5v-3a-5v-1-5a-133.html#post6210711
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Thank you for shooting yourself in the foot. As expected, the reference above is nothing but a blank statement that, of course, fits your agenda:
A sound quality problem was found by listening, then tracked to it its source which was found to be RFI. After removing the problem, a very slight improvement in AP measured distortion was observed. The sound quality improvement was significant, the measured distortion improvement was insignificant.
That's my interpretation of what I think cdsgames was saying.
My point was mostly that AP does not especially measure for RFI effects. Since RF is much higher frequency than audio, any RF-caused effects in the audio band have to stay constant long enough for for an audio frequency FFT to be taken (possibly including time for averaging out uncorrelated noise). That may be pushing things in a way that does not capture the magnitude of some possible Rf-caused problems very accurately. To put it another way, what the RF may do is produce some ugly sounding noise rather than produce HD of audio frequencies. Either way, it could affect perceived sound quality.
That's my interpretation of what I think cdsgames was saying.
My point was mostly that AP does not especially measure for RFI effects. Since RF is much higher frequency than audio, any RF-caused effects in the audio band have to stay constant long enough for for an audio frequency FFT to be taken (possibly including time for averaging out uncorrelated noise). That may be pushing things in a way that does not capture the magnitude of some possible Rf-caused problems very accurately. To put it another way, what the RF may do is produce some ugly sounding noise rather than produce HD of audio frequencies. Either way, it could affect perceived sound quality.
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This, to me, is the interesting bit. How can it be known there was a problem with fidelity by listening, what was compared?
If you listen to human voices or other things you know the sound of in reality, and it sounds like a belt sander or a power saw is running in the background at a low-ish level and garbling the sound (at a low-ish level), you can be pretty sure its not supposed to be in a recording of a human voice singing music.
Strange, that this site that answers it all, has not been mentioned in this thread at all,
it is worth an evening of reading.
I.e. two Dacs in the price range of 99-200$ are among the top ten.
Many known names are just mediocre.
A 15.000$ boutique Dac bombed and delivered the worst measurements.
I assume almost a hundred DAC´s have been tested:
The thread starter will find his DAC there.
Articles, Reviews and Measurements of Audio Products | Audio Science Review (ASR) Forum
it is worth an evening of reading.
I.e. two Dacs in the price range of 99-200$ are among the top ten.
Many known names are just mediocre.
A 15.000$ boutique Dac bombed and delivered the worst measurements.
I assume almost a hundred DAC´s have been tested:
The thread starter will find his DAC there.
Articles, Reviews and Measurements of Audio Products | Audio Science Review (ASR) Forum
Maybe I haven't read it carefully enough, but I didn't see anything about headroom for intersample overshoots or passband ripple (at least not in the Donald DAC review, I didn't check any of the others).
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