efaq: Turning the volume down
5.25 How do I turn down the bell volume in Emacs running under X?
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On X Window system, you can adjust the bell volume and duration for all
programs with the shell command ‘xset’.
Invoking ‘xset’ without any arguments produces some basic
information, including the following:
usage: xset [-display host:dpy] option ...
To turn bell off:
-b b off b 0
To set bell volume, pitch and duration:
b [vol [pitch [dur]]] b on