Sometimes weirdness is instructive.

Had Opera & ET running fine and dandy through a chroot on Debian latest sid32/etch64 but today I rebooted and sound failed.

Local mplayer etc apps worked fine.

Eventually noticed that /dev/dsp had evaporated. No idea where it went but running ./snddevices sorted it out just fine.

Probably worth making sure your chroot'd user is in the audio group and that the various /dev/dsp adsp mixer files are audio group aswell.

As you may have guessed, after years of OSS devotion I have succumbed to the evil of ALSA :-(