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

[Olivier Guilyardi]

Hi

fons adriaensen wrote:
> On Mon, Jun 06, 2005 at 08:18:22PM +0300, Juhana Sadeharju wrote:
> 
>>Because I don't want build anything, I would record
>>drumming on whatever I find from our kitchen.
>>The software should detect the pitch and volume
>>of the hits.

I said pad not pan ;-)

Well, that's an idea, but you'll be playing alone then. Because if some bassist 
or guitarist is around, you'll end up with a drum symphony :-) But I like your 
idea, and it's basically the idea of so-called guitar-synths. If you don't want 
to build anything though, you can also buy yourself some cheap/second hand 
Yamaha pads.

With some quality piezo microphone and a carefully chosen playing surface, 
analysing the frequency in order to alter the resulting sound, or trigger 
different notes/samples can be interesting. In this case though, the mic would 
still be sticked to the surface so that you don't catch unexpected sounds.

> Using two separated mics will make things easier, as you
> can then also use the time difference to separate sources.

I see... "No please don't touch the coffee cup, it's exactly at 4 ms from the 
frying pan" ;-).

Using several mics in this way can be interesting.

I now have some clearer idea of a first implementation of a trigger2midi 
application :

- It could run headless, but would have a GUI to adjust trigger settings
- This GUI would generate a simple, editable trigger description text file
- It would run on Jack
- The settings for each trigger would be :
     - gain
     - level range, to ignore signals below and above a certain level, and
       possibly issue different midi program/notes according to the level
     - frequency range, to allow using a single mike for several triggers
     - midi port/channel/program/note
     - the source could be :
         - either one Jack port
         - or two Jack ports with a "pan range" (back in the kitchen ;-)
- One could add as many triggers as needed, and the GUI would show visual meters 
to easily test the settings while they get adjusted.

The pan setting would allow to use 2 microphones with a time difference, and 
should be easy to find with an automatic routine : after plugging the two Jack 
ports in, you'd click on a "Capture pan" button and hit an object. The 
difference would then automatically be captured as two values, to allow a 
certain position range. You could then precisely adjust the two edges of this range.

I guess that with a sophisticated frequency range measuring routine, one could 
for example use a guitar with many triggers, to produce a wide range of 
sounds/notes.

The Alesis D4 and DM5 devices also offer a "vcurve" parameter : that's a 
sensitivity curve, for non-linear midi-velocity/signal-level relations. That 
could be an advanced setting.

Cheers

--
   og