Dumb question,

As I sit here listening to "June" off of Camper Van Behtoven's Key Lime Pie album, I have noticed the following. In XMMS (and any audio application for that matter), files sound different depending on which audio output driver I use. OSS Sounds different than ALSA. ARTS sounds different than ESD. ARTS on ALSA sounds different than ARTS on OSS. ALSA w/dmix sounds different than ALSA wo/dmix, and so on....

So the question is... Why is this? Digital audio stays digital all the way to the DAC, why would one delivery method differ in fidelity from another? It appears that straight ALSA offers the best fidelity of all the options.

Thank you for your time,
Frank Russo

not a dumb question at all but a hard one to answer
alsa is a buffered software abstraction layer to the hardware
the other things interact using different sound routines that either suck or suck less.
all have some level of software latency that interacts with the functioning of the alsa ring buffer
some might mess with gain or other parameters in some way.
often the player sucks and interacts with an output plugin that sucks that interacts in some sucky way with the sound server that sucks that then interacts with the alsa abstraction layer that sucks less
the best server seems to be jack at least here it sucks least of all.