DAC Differences
Audio_Empire wrote:
In article ,
Andrew Haley wrote:
Audio_Empire wrote:
And, if it measures different, it can sound different. Most DACs do
measure differently. These measurement differences are not so much
things like frequency response and distortion + noise (which tend to
be very low, and usually below the threshold of hearing. but are
things like the undithered sinewave waveform shape, jitter spectrum,
impulse response, etc.
First, let's clear up a misconception. An imperfection in a DAC will
be manifested as linear distortion, nonlinear distortion, or noise.
Jitter is nonlinear, and will cause IMD. Different impulse responses
are probably due to phase shifts. An imperfect undithered sinewave
waveform shape could be due to anything, but is probably just noise.
everything you say is correct. The only questions is how much of these
linear and nonlinear distortions or this noise is above the threshold of
hearing?
Well, you can see the amplitudes of these on a spectrum analyzer. The
absolute thresholds of hearing at any frequency are in Zwicker and
Fastl, as is information about the effects of masking on those
thresholds.
Obviously some of it is, or all DACs from a $50 Chinese DAC box
bought on E-Bay would perform exactly like a $14,000 DAC box from
MSB.
Not necessarily: it's quite possible that the $50 Chinese DAC box has
some nasty nonlinearites due to very cheap design.
Hint: they don't.
Why is the undithered sine wave interesting, anyway? It can't happen
in any recording. I suppose it makes an interesting-looking picture.
I don't know. Ask John Atkinson of Stereophile. They are part of the
suite of tests he uses to test DACs and they do show a degree of noise
modulation and that degree does differ with different DAC models.
I know, but I suspect that the only reason to print those is to show
something that is measurably different.
Andrew.
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