[linux-audio-dev] Software controller for homemade edrums

From: Olivier Guilyardi <ml@email-addr-hidden>
Date: Thu Jun 02 2005 - 01:56:12 EEST

Hi,

Assembling piezo microphones, cardboard, foam, wood and a cymbal stand,
I have just made my first DIY electronic pads. Actually it's electronic
percussions, because I will play these mostly with hands.

I've found a few sites about DIY "edrums" (1), as well as some detailed
documentation about how to build a trigger-to-midi hardware controller
(2). But since I started this little project, I've been thinking about
plugging the piezo mikes directly into my soundcard inputs. My first
tests are very good : the signal is clean, and indicates faithfully how
hard the pads get hit.

I am now about to code a software controller to :
1 - either interprete the signal and produce midi (or OSC) events
2 - or interprete the signal, and play samples by itself, in a
standalone manner (no midi)

I tend to prefer the second option, for the following reasons (criticism
welcome) :

- I want to reduce latency _as_much_as_possible_ (keeping the rythm is
hard enough ;-). To me, the midi layer introduces useless buffers

- I'd like the whole thing to use minimal resources, so that I can run
it on old hardware (simple boxes to be carried in studios and on stage).
In this regard, a small tool built upon Alsa, which run without any
sound server or midi layer, looks to me as the lightest solution

- I don't want to use harware expanders, such as the one that is built
into my soundcard. I want to play samples. With midi, I would then need
a such tool as Timidity, which is pretty heavy according to my latest
tests. Jtrigger seems lighter (http://sparked.zadzmo.org/jtrigger), but
it relies on Jack : I like Jack, but it seems too heavy to me, for this
specific job.

- In regard to clicks and other noises, I believe a lightweight
application running on a dedicated barebone Linux system is more
reliable than a realtime thread with a complex layer as Jack, especially
on slow hardware.

Are these good/coherent reasons to you ? Do you have any other advice ?
Is there already some software that could help me, or some pieces I
could reuse, to achieve any part of this process ?

Best regards

References :
(1) http://edrum.for.free.fr
(2) http://www.midibox.org/edrum

--
  og
Received on Thu Jun 2 04:15:10 2005

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