The sound control on lxpanel only handles one channel. But let’s say I want to control mute/unmute on mic by a handy shortcut! Two handy scripts fixes this, which can be assigned to a keyboard shortcut in Openbox or your preferred WM/DE.

amixer set Mic 80% mute > /dev/null
amixer set Mic 80% unmute > /dev/null

You may of course choose any other control you want – ie PCM:

amixer set PCM 10%+ > /dev/null

Will increase sound by 10%.