Re: Data denstiy on disc (Re: HD is the future of radio (according

Doug McDonald wrote:
On 12/9/2010 3:37 PM, Richard Evans wrote:

Obviously to use dither, you need the sample rate to be several times the frequency of the sound
that needs to be dithered.

Incorrect. Merely having the dither in the highest octave will work, even
if the signal is only sine waves up there.

But how on earth can you have dither in the highest octave. To use dither you need the values of several samples to be averaged out over time. In the highest octave there are only just enough samples to describe the waveform, there wont be enough additional samples to be averaged out.

Obviously though this doesn't actually matter, as at the highest octave the ears aren't very sensitive to detail, so there is no need for any dither anyway. The ears are far more sensitive in the midrange, and this is where dither can be very useful.

Unless of course you are talking about using higher sampling rates, but that's a slightly different subject. We were talking specifically about CD here.

Richard E.