I have to go now and I'm away for the weekend but I'd like to continue this discussion next week. If we really can't hear much above 15 kHz then why does SACD/DVD-A sound more natural and less edgy than CD? Is it perhaps just an extension of the oversampling/upsampling theory, i.e. that you can use a much more benign filter if your DAC works at a higher frequency than 44.1 kHz, and that sample rate actually has not a lot to do with it?

I'll be back. What's more I'll be back with diagrams! I would really like to know how a DAC reassembles a 21 kHz pure sine wave from a 44.1 kHz pulse train.

Have a great weekend! I intend to