D/A and A/D | Digital Show and Tell (Monty Montgomery @ xiph.org)
This is a video about the digital vs analog audio quality debate. It explains, with examples, why analog audio within the accepted limits of human hearing (20 Hz to 20 kHz) can be reproduced with perfect fidelity using a 44.1 kHz 16 Bit digital signal.
There is no audible difference between an analog and digital audio signal.
Among other things, xiph.org maintains the .flac and .ogg vorbis audio formats - they know a little about audio encoding and reproduction.