Re: Midi Harp.

[William Lippe <lippe@xxxxxxxxxxxxxxxx>]

On Mon, 9 May 1994, Spence Pearson wrote:

> 	Gordon seems to be knowledgable about midi technology. I wonder 
> if he or anyone who knows would explain, in layman's terms, just how an 
> air flow in 2 directions can be transduced with a high degree of sensitivity.
> For instance, how does the midi saxaphone do it? Just tell me how to make 
> one and I'll get on it.
> 		-Spence
------>
Ideas of the top of my head...
A set of reeds which actually don't produce sound, but are used only to 
sense the air flow..
The Bernouli effect is whats driving the thing, so a hole going straight 
through the comb, with some odd sized, shaped hole would still allow the 
pressure in the channel to rise and fall, and a thin plate of something 
would be mounted (airtight of course) to the top, and would sense the 
pressure changes.
Find other instruments which measure airflow, and I don't mean musical 
only, and adapt their devices.
You don't have to have full movement of the reed.  A very stiff reed 
would be displaced different amounts by differing pressures, which 
wouldn't be operating on the same principle, but...
This one's totally wacko, some sort of device, which lets the air out 
along a slot in a tube, which slides in and out, with a spring pressing 
in, a very delicate spring.  So a small breath would push the cylider out 
a small amount, and the displacement would trigger the MIDI.  A larger 
breath would move the cylinder out further, which would increase the size 
of the hole for escaping air, so I guess the intensity would taper in 
relation to the k of the spring, and I bet there is some spring which 
would simulate the response of a harmonica pretty well.
I've got a lot more ideas for this, and the other variables, but if 
you're building one and want ideas, just mail me direct...