I am letting out a huge mad scientist laugh right now.
I had a suspicion that a big part of the Hammond B3 sound is the resonance of the wood in
the speaker cabinet. Particularly down in the lower registers, or when the crosstalk from
the 16' is audible. It sounds like the wood gives that extra "thump" on the
attack.
So I grabbed my EEE with a copy of Aliki, and made my way to a studio with a Leslie and
some nice mics and outboard gear. And I captured some impulses of the Leslie.
Then I ran the impulse in JCONV, and ran Beatrix thorugh that:
http://www.restivo.org/blog/podpress_trac/web/492/1/lesliedemomix.ogg
And it turns out, I was right. The percussive sounds are indeed caused by the wood
resonating. Except there is no wood. Every noise you hear there is coming out of an EEE
running Linux. There is no actual Leslie. It's a convolution reverb.
I have published the impulses here, in case anyone wants to play with them:
http://restivo.org/projects/leslie/ CC-BY-SA licensed, have fun. There's some README
in the tarball, and also a sample JCONV conf file for using them.
I'd imagine that not only Beatrix, but also AZR-3, or any other organ emulator, even
an FM synth, would sound pretty good through Leslie impulses too.
-ken