3 ms·

Perhaps the 16-bit sample really did sound better in some cases? The lowest bits of a D/A converter are the most non-linear. By avoiding them you might get a m

by mark-r 12y ago

Perhaps the 16-bit sample really did sound better in some cases? The lowest bits of a D/A converter are the most non-linear. By avoiding them you might get a more accurate waveform overall. This would explain the people who were confident that they knew which was which, even when they got it consistently wrong. It would depend greatly on the specific D/A converter so you'd expect it to go both ways.

cnvogel 12y ago
Sorry, but no! 1.0 1.1 1.9 2.0 2.1 2.9 3.0 is still a better approximation of a linearly increasing list of numbers than 1.0 1.0 2.0 2.0 2.0 3.0 3.0 and I doubt that any 24bit DAC or ADC in existence will interpolate as bad as I did in this example. Whatever distortion due to quantisation the latter creates, the former will create less of it.
- emn13 12y ago
  Notably, with such a small sample size and multiple testing, it's to be expected to see small deviations in preference such as the one in the article. The article mentions p=0.28, which isn't entirely easy to interpret given that he doesn't quite explain what that p value is actually measuring (did he correct for multiple testing, for instance?), but it's certainly not a claim of any meaningful significance.
- mark-r 12y ago
  Your example is overly simplistic. Dithering is what allows a low bit sample to emulate a high bit one, and I don't see any evidence that you applied any; even if you did you wouldn't get a feel for how it operates with such a short sample.
  - cnvogel 12y ago
    The initial statement was: "lowest bits of a D/A converter are the most non-linear. By avoiding them you might get a more accurate waveform overall." You can of course apply dithering to any signal to mask quantization noise. It's just that a perfect N-bit DAC will require less dithering to mask its quantization distortion/noise than a non-perfect/not-quite-linear N-bit DAC which again will introduce less quantization distortion/noise than the (N-k) bit DAC. In fact, you could say that a N-bit DAC is just "perfect reproduction" plus a non-linearity that amounts to the step-width of 1-LSB, e.g. it's resolution. And a 24-bit DAC that unfortunately is off by 8 LSB (2^3) along its 0...2^N-1 to 0V..Uref curve is still as good or better as a 21-bit DAC (24bit-3bit) in reproducing a waveform, and still better than a 16 bit DAC. A graphical representation of this is commonly found in datasheets and called "integrated non-linearity."

by mark-r 12y ago

cnvogel 12y ago

Sorry, but no! 1.0 1.1 1.9 2.0 2.1 2.9 3.0 is still a better approximation of a linearly increasing list of numbers than 1.0 1.0 2.0 2.0 2.0 3.0 3.0 and I doubt that any 24bit DAC or ADC in existence will interpolate as bad as I did in this example. Whatever distortion due to quantisation the latter creates, the former will create less of it.

emn13 12y ago
Notably, with such a small sample size and multiple testing, it's to be expected to see small deviations in preference such as the one in the article. The article mentions p=0.28, which isn't entirely easy to interpret given that he doesn't quite explain what that p value is actually measuring (did he correct for multiple testing, for instance?), but it's certainly not a claim of any meaningful significance.
mark-r 12y ago
Your example is overly simplistic. Dithering is what allows a low bit sample to emulate a high bit one, and I don't see any evidence that you applied any; even if you did you wouldn't get a feel for how it operates with such a short sample.
- cnvogel 12y ago
  The initial statement was: "lowest bits of a D/A converter are the most non-linear. By avoiding them you might get a more accurate waveform overall." You can of course apply dithering to any signal to mask quantization noise. It's just that a perfect N-bit DAC will require less dithering to mask its quantization distortion/noise than a non-perfect/not-quite-linear N-bit DAC which again will introduce less quantization distortion/noise than the (N-k) bit DAC. In fact, you could say that a N-bit DAC is just "perfect reproduction" plus a non-linearity that amounts to the step-width of 1-LSB, e.g. it's resolution. And a 24-bit DAC that unfortunately is off by 8 LSB (2^3) along its 0...2^N-1 to 0V..Uref curve is still as good or better as a 21-bit DAC (24bit-3bit) in reproducing a waveform, and still better than a 16 bit DAC. A graphical representation of this is commonly found in datasheets and called "integrated non-linearity."