Charles> Skip - did you try "fuser /dev/dsp" ?
Not until you suggested it. Didn't even know it existed. It displayed
nothing for either /dev/dsp or /dev/audio0:
% fuser -a -v /dev/audio0 /dev/dsp
USER PID ACCESS COMMAND
/dev/audio0
No process references; use -v for the complete list
/dev/dsp
No process references; use -v for the complete list
Skip