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Re: nonsense

Bwaslo, you should have more experience before commenting.
First, sound cards DO effect the sound. IF they didn't, we would pronounce them perfect and not go any further. It would mean that if I added the AD-DA converter that I purchased for less than $200 on sale, from Leo's Music, a pro audio outlet, in series with my preamp, that it would be perfectly inaudible. We have found that this sort of thing IS audible.
Next, you act as if we think that all the subtle changes that we make in audio can be made obvious to everyone, everywhere, with cost effective audio equipment. No it can't, BUT we can detect differences in our own equipment that we have become used to, with audio sources that we know are recorded to a very high standard of quality.

Technically, this difference test, while potentially being an important tool, will suffer from the limitations of the sound card. Perhaps, not as much as normally, because some of the more obvious harmonic and IM distortion will be cancelled out, that was generated by the op amps before and after the A-D processor, but the noise will still be added and will be at least 3 dB higher than the wire as it would normally be evaluated. This is because the subtraction of the coherent parts of the signal will not cancel the random effects of the noise from both samples taken. In effect, I would think that I would see mostly noise in the error signal. Another big problem is phase differences at both low and high frequencies. This might not be too much of a problem with a wire, but a component (such as a cap) would seriously suffer differences with another component.
It would seem that only the simplest things, like a wire, could be tested easily with this device without linear distortion adding and confusing the error output.
Another really important factor is the OMISSION of information caused the the sound card. If the sound card was so good in the first place, would it omit infomation? Listening tells me that it does do just that. If you omit information, how do you get it back, to see how it has been changed?
It should be noted that we have been trying to do this sort of thing for decades. We did it with 10 bits and a 50KHz clock rate, 1/3 of a century ago. We could not see any significant differences in good (Levinson JC-2 level) op amps, and I have always wanted even more resolution like 16 or even 24bits, but like Jon Risch, I doubt that it will be very effective. However, it would be a Godsend for us, IF it really worked.


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