I am a graduate Electrical Engineering student. I absolutely disagree with your point that analog filtering is considered superior to digital. The vast majority of sound processing is digital these days, ask anyone in the industry. If you do not wish to implement an equalizer, then simply say no, but do not pretend like you are walking the righteous path by saying so.

I stand corrected :D. Thanks for the interesting knowledge. Avuton Olrich 03:24, 3 December 2007 (UTC)

LADSPA Edit

Instead of using JACK (which I couldn't get to work on my Gentoo system), ALSA and LADSPA can be used to get an EQ. I used the LADSPA dj_eq plugin that can be found here (or emerge swh-plugins on Gentoo). It's a 3-band equalizer, so there's only basic control over lo, mid and hi.

Here's my ALSA setup:

pcm.ladspa {
    type ladspa
    slave.pcm "plughw:0,0";
    path "/usr/lib/ladspa/";
    plugins [
        {
            label dj_eq
            input {
                controls [-25 0 0]
            }
        }
    ]
}

pcm.mpd_out{
    type plug
    slave.pcm "ladspa";
}

And here's the audio_output setup in my mpd.conf:

audio_output {
    type    "alsa"
    name    "My ALSA Device"
    device  "mpd_out"
}

The controls [ll mm hh] part in the alsa configuration passes control parameters to the dj_eq plugin: it sets the lo (100Hz), mid (1kHz) and hi (10kHz) gains measured in dB for the audio output ([1]). As you can see, I needed less bass.

There's also a multiband EQ plugin available at the same site, but I haven't tried that one (yet). The control parameters are listed here, it seems. YMMV

Using LADSPA plugins for ALSA apps

Hope this helps

Steeffie 23:24, 7 April 2008 (UTC)