^ Syn08's quote is from Mark, yet points to Scott's post which says something different. I mean they're interrelated, so it's fine-ish.
Yes. I had a long post prepared in my head about the balance between Engineers enjoying telling war stories about how they had traced the cause of X to mouse pee (real LIGO war story) vs how embarassed they might be on making a college level mistake on a serial interface and certainly wouldn't want to use it in marketing gumf but realised it's friday night, I've been drinking and fingers and brain are not currently in sync 🙂
Might or might not work. RFI may have been from dac MCLK affecting I2S clocks. Gate MCLK and the dac stops. Besides, we don't know the process in the dac that makes the RFI audible at the output. The biggest problem of course is proving that something small looking on an FFT can be audible. Maybe some noise floor modulation of the dac going on too. Slower gating of the interference might show something there. Since we can't gate MCLK, maybe we could use an electric motor to periodically spin a piece of shielding material around where the RFI coupling is taking place, that would be cute.
If you listen differently, it will sound different even if no component is changed.
You forgot to mention where the DVM, the 100MHz oscilloscope, and the shortwave radio are involved.
If the result agrees with what he wants. If not, "Those are designed to trick the victim into false negative results." in his view.
I have mentioned before I built an RF test chamber that can hold the device being tested and has XLR style inputs and outputs. I have a modulated variable frequency RF oscillator that feeds a wideband RF power amplifier that has the output just padded enough that mismatches will not damage the RF amplifier.
Very easy to test audio gear with a not very complicated reasonable cost setup.
Very easy to test audio gear with a not very complicated reasonable cost setup.
Proving all of this will not be for the indigent, sorry for your situation. However, when it comes to the audibility test, that only requires some effort and free software. Do it. Prove that two largely similar setup sound demonstrably different, and I am sure you will be able to find plenty new rich friends with measurement gear.
Even the cheapest cables now use polyethylene. And this is also not an ideal dielectric, like air or vacuum. Therefore, in more expensive cables, foamed polyethylene, foamed Teflon or even a thin Teflon spiral is used as a dielectric to reduce the contact area of the dielectric with the conductors. And all this was invented back in the 50s, as soon as these materials and technologies became available, that is, long before the advent of the DAC. To measure the effect of dielectrics, then, as you suggest, you need accuracy an order of magnitude higher than what you indicated. In the 1950s, they acted much more simply, they measured the speed of signal propagation in the cable in relation to the speed of light, and this is absolutely no secret information, since it is still published in cable specifications of many manufacturers. Of course, you ask again if I will hear such distortions. My question to you is what kind of distortion do you ask all the time? Then let's talk.
When you think that strawberries taste better than cherries, why not simply being happy with this experience instead of trying to convincince others with your believe that they really do taste better.
I do not share Scott’s opinion on cables, but I fully respect his judgement.
When we all think and feel the same, the world becomes very very boring.
Hans
I would never have thought or intended to do this, but I assure you, I also feel the difference between these berries, despite the fact that some are trying to convince me otherwise.
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Well, I do have doubts on anybody’s long term memory, as also I am always interested on the context of past calls, so I did a detective search on you input in this site. 🙂
Search filter: noise floor + anything digital
(from earliest to latest post)
John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part III
John Curl's Blowtorch preamplifier part III
John Curl's Blowtorch preamplifier part III
John Curl's Blowtorch preamplifier part III
John Curl's Blowtorch preamplifier part III
John Curl's Blowtorch preamplifier part III
The Black Hole......
George
In connection with noise floor modulation and Howie's posts, my own recollection was that Howie provided the most information about hearing the noise modulation in a post about listening with headphones at very low level playback levels with his Auralic Vega dac. His post may have been in response to other discussion about whether dac noise floor modulation could ever be an audible effect or not. The original reference to it I saw was a brief mention by Martin Mallinson in Sabre dac white paper which I believe is still available from the ESS website. IIRC Mallinson said something about it being audible to some 'very perceptive' listeners. Again IIRC, Howie confirmed that it was a real effect, annoying, and it could be audible under some particular circumstances.
That was enough for me at the time since I was only trying to show that there are at least some some audible differences between dacs that at least some people can hear. Noise floor modulation was just low hanging fruit in that effort since it had already been mentioned by a couple of credible sources.
Personally, I have never tried listening for noise floor modulation myself and would not say that I can hear it. However, I do still hear other dac differences as do other people. I did notice Howie mentioned (in one of the posts George found) that some dacs from the early 2000's had some 'grot.' Howie, my friend, some still do have some of that but it now takes a better reference dac to confirm its still a problem in lesser dacs.
That was enough for me at the time since I was only trying to show that there are at least some some audible differences between dacs that at least some people can hear. Noise floor modulation was just low hanging fruit in that effort since it had already been mentioned by a couple of credible sources.
Personally, I have never tried listening for noise floor modulation myself and would not say that I can hear it. However, I do still hear other dac differences as do other people. I did notice Howie mentioned (in one of the posts George found) that some dacs from the early 2000's had some 'grot.' Howie, my friend, some still do have some of that but it now takes a better reference dac to confirm its still a problem in lesser dacs.
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Your post would have more credibility if accompanied by supporting evidence.
Why do you label that a problem?
As equally a stretch as your original argument, to be honest. Take 5 minutes and write out the number of implied assumptions and you realize that it's got more holes in it than an aerogel. If you can't find a significant convincing rebuttal to that argument then you aren't trying at all.
If you notice that sort of trend like that, great. You have a nice hypothesis to start with.
Actually I can summarize my inexcusable verbosity by this one paragraph I posted on 17th January 2016:
"... That much average listening levels involve all 16 bits and therefore the acoustic noise floor is ~15 bits lower (after the addition of dither). Much music has a crest factor of 20dB or more, so the effective number of bits being used during much of the program uses more like 12 bits or less. That it can sound as good as it does is a testimony to the effectiveness of dither."
And although re-examining the tracks I have analyzed recently I would revise that statement to "many tracks have a crest factor of 14 dB or more." ...and that is probably ALL I should say, not having recently done tests with which to deliver data to you folks.
Cheers and enjoy your weekends! I'm out to mow after days of rain...
Howie
https://www.diyaudio.com/forums/dig...ical-i2s-send-receive-boards.html#post6220128
This looks like exactly the sort of thing we were discussing a while back. Will be interesting to see what costs come out at.
This looks like exactly the sort of thing we were discussing a while back. Will be interesting to see what costs come out at.