code ALSA equalizer
libasound2-plugin-equal - equalizer plugin for ALSA
$ vim ~/.asoundrc
ctl.equal {
type equal;
}
pcm.plugequal {
type equal;
# Modify the line below if you don't
# want to use sound card 0.
slave.pcm "plug:dmix";
}
# pcm.equal {
# Or if you want the equalizer to be your
# default soundcard uncomment the following
# line and comment the above line.
pcm.!default {
type plug;
slave.pcm plugequal;
}
# alsa force-reload
$ alsamixer -D equal
$ vim ~/.bashrc
alias alsaequal='alsamixer -D equal'