Beatrix

From Arnout Engelen

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This software MIDI synth has a sweet organ sound.

Contents

[edit] Inputting though ALSA MIDI

Beatrix works with 'raw midi' rather than the more common ALSA midi. Luckily, ALSA can emulate 'raw midi':

  • modprobe snd_virmidi
  • some /dev/snd/midi* devices should appear
  • modify default.cfg to point to a /dev/snd/midi* device

Now you can connect applications to beatrix like normal, for example though the ALSA tab of qjackctl

[edit] Outputting via ALSA

Beatrix uses the OSS /dev/dsp interface for output. I liked to use beatrix simultaneously with other applications (like Transcribe!), so I wanted to wrap the ALSA compatibility layer around it with aoss.

This sort worked when I set pcm.dsp0 as a plug to hw:0,0 in my .asoundrc, but obvously that won't do since it'll block it (my card doesn't do hardware mixing afaik). When plugging it to dmix, it gave a SNDCTL_DSP_SETFRAGMENT error. I turned that error into a warning, but the sound was indeed awfully distorted.

The key turned out to be turning the errors into warnings and plugging the pcm.dsp0 to "default" (only in newer versions of ALSA i'm told).

[edit] Latency

Unfortunately this introduces a noticable latency which makes this solution useless by itself. I guess I should be looking into latency-reducing measures.

[edit] Manipulating the sound

Configuring the sound works by sending program change events.

I created a vkeybd preset file for Beatrix that makes it easy to modify the sound from vkeybd.

[edit] Licensing

Beatrix is free-as-in-beer and comes with sourcecode.

Too bad the license doesn't allow redistribution, not even unmodified redistribution. That might make it much more popular

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