[sdiy] Thoughts on drum synth

[Chris Stecker]

Hey,

This is a really great thread.  What a great mix of analysis, design, and 
aesthetic considerations.  I really like the idea of a 6-resonator analog 
drum model.  In a real drum, where you hit it and when how and where you damp 
it all control the interaction of the modes.   As a first pass, you might 
just control the amplitude mix of the various modes in a way corresponding to 
"where" the "drum" is "hit"

On the second pass, you might consider how they couple.  Coupling of the 
modes might suggest a design using a series of damped hi-q filters rather 
than oscillators.  Each filter could be excited by an impulse initially, but 
after that is also excited by the (decaying) activation of the other filters. 
Another advantage is that you can derive different models for the driving 
source, corresponding to hard sticks, soft mallets, vibrators, loose change, 
whatever.

On the third pass, you might start to consider active damping.  A hand 
drummer can lay a finger at a certain spot to kill this mode or that.  Or use 
a soft tap to damp the bulk of the sound while one or two upper partials 
continues to ring through to the next hit.  

Regardless, it would be really neat.

Thinking of controllers, this thread brings to mind Buchla's Thunder 2 / 
"ThunderKAT."   Anybody else seen one?  It uses a real drum head, 
reflectively coated on the underside, and a pattern of leds and photosensors 
is used to detect the place, pressure, and timing of multiple impacts.  
Really really cool, but as far as I know it lies dying in the distribution 
pipeline (maybe a deal fell through or some company killed the project).  
These thoughts are my own speculation.  I've seen the device (working) and 
heard some rumors, but really don't know much about the fate of Thunder 2.   
Anybody else know more?

-Chris