Linutop2: Alsaequal 0.4 for Ubuntu 9.10 (.deb package)

Posted by – 2010/01/05

Ever wanted a snazzy equaliser for your linutop2/(or any AMD geode-based nettop) but were afraid to ask?

Built today under the influence of cli-guru kmandla and following some simple build instructions at debian.net. Based on alsaequal 0.4 If you’re running a headless, X-less linutop2 as your boombox like I do, a good cli equaliser is pretty damn valuable.
A couple of prerequisites for this guide: a working alsa-based sound setup, mpg123 and/or vorbis-tools (ogg321) for playback.


grab it here or open your favourite xterminal and start pasting :)
wget http://www.fileden.com/files/2010/1/5/2714416/alsaequal_20100105-1_i386.deb
sudo apt-get install caps
This will install the CAPS Audio Plugin Suite, the main dependency (if you find others please let me know).
Then you sudo dpkg -i alsaequal_20100105-1_i386.deb
to install the equaliser itself.

Halfway done here, we need to save the following to ~/.asoundrc

#not really necessary
#I just aliased the default csaudio geode companion to pcm.csaudio
pcm.csaudio {
type hw
card 0
device 0
}

ctl.equal {
type equal;
}

pcm.plugequal {
type equal;
slave.pcm "plug:csaudio";
}

pcm.equal {
type plug;
slave.pcm plugequal;
}

Force-reload all your alsa modules with sudo alsa force-reload
and start EQing with alsamixer -D equal
To verify that your setup is configured correctly, try to play back an mp3 with mpg321 -a hw:equal, forcing mpg321 to use the recently created ‘device’.
Now for the actual EQ’d playback. I have not managed to make cmus work with the equaliser (shame cause it is my audio player of choice) but it will work without a hitch in mpg123 , ogg123 and by extension, the now obsolete cplay. To make cplay use the correct parameters for mpg321/ogg123 open your favourite
editor and save the following lines to ~/.cplayrc

PLAYERS = [
    FrameOffsetPlayer("ogg123 -a hw:equal -q -v -k %d %s", "\.ogg$"),
    FrameOffsetPlayer("mpg321 -a hw:equal -q -v -k %d %s", "(^http://|\.mp[123]$)", 38.28)
    ]

The only drawback to this form of EQing is a rather increased CPU usage during playback. It jumped from an average 10-15% to 30-35% (the LX800 is not exactly a performance CPU anyway).
EQing is done in real-time so to speak (there is some inherent latency that cannot be avoided) so I suggest you run your equaliser in a separate gnu screen window for fine-tuning as you listen to your reference audio.

DISCLAIMER since YMMV:
THERE IS NO WARRANTY FOR THIS GUIDE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. i.e. if you botch up by trying to adopt this guide for a different setup, just erase ~/.asoundrc , force-reload alsa and you’re back where you started :)

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