Hi!
You could use ladspa-plugins to do so. There are several EQs, that do what
you need. There's Steve Harris' eq (ladspa ID 1199 I believe) and then there
is Fons Adriaenson's parametric Filter, which you can download from his site.
It's better suited to the task, I think. It only has 4 bands, but there are a
lot of possibilities to configure the bands. Besides there is an EQ in the TAP
plugins.
You can find links to them all on
http://linux-sound.org
or at
http://apps.linuxaudio.org
To involve them into your alsa system (app-independent) there is an
alsa-plugin, that supports ladspa-plugin integration. I don't know the exact
syntax or the name of the plugin. But you could have a look at
http://www.alsa-project.org
Look for asoundrc. It's a configuration you do in your .asoundrc in your
home-directroy or in /etc/asoundrc (not 100% sure about the latter name, never
did it).
Hope that helps. If you've more alsa-specific questions. You could try on
this list or directly mail to the alsa-user list.
Kindest regards
Julien
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