convolution

[David Halliday (Volt Computer)]

You could use a blank pistol - the kind used for starting athletic events
etc...

-----Original Message-----
From: Martin Czech [mailto:martin.czech at intermetall.de]
Sent: Thursday, October 28, 1999 5:25 AM
To: synth-diy at mailhost.bpa.nl
Subject: convolution


I have a question concerning reverb:

If I could record the impulse response of a room (say with my portable
dat), I could take the reverb of this room home to me. This works.

But how can I obtain a impulse response if I don't have anything that
makes such a impulse. I could clap in my hands (not very reproduceable)
or use two pieces of wood etc...

My idea is: 
I could build something like is used in movie studios: two pieces of
wood and a joint. Ok, this would give a loud, more or less reproducible
clap. But this doesn't look like an impulse, probably more like an
exponentially damped wave. Now, I could record this sound, say in "free
air" with neglegible reflections. I could compute the DFT. The "free-air"
clap represents a filter, with strange impulse response.