Re: [LAD] Leslie and convolution

From: Gene Heskett <gheskett@email-addr-hidden>
Date: Thu Jul 26 2012 - 20:49:20 EEST

On Thursday 26 July 2012 13:37:45 Julien Claassen did opine:

> Hello again!
> So the very short answer would be: It's not been done inany Linux
> software yet.
> Thanks for the explanations. I have thought a little too simple it
> seems and the outcome is what I originally expected. No go. :-)
> Kindly yours
> Julien

Speaking as a bit of an engineer, to do a Leslie simulation would require
that something like a bucket brigade be done with the digital data once
decoded, then setup a pair of taps that would sample the digital from the
brigade , advancing the signal in time for the speaker nearest the
listener, and delaying the other half of the mix equally. Then combine it,
and send it on down the path to the speakers, or perhaps to 2 separate
speakers, but the 2 speaker approach would add its own artifacts. What you
are then building is in essence similar to a comb filter with a variable
clock speed.

And this effect would only be valid for a stationary listener, because the
bucket-brigade would have to get longer for the angle being synthesized
according to where the listener is. The farther off the centerline, the
longer the brigade, up to the time lag representing the maximum separation
of the actual speakers on the Leslies rotating board. I'm sure some
curious coder could work out the math, but the bucket-brigade would
probably have to be done in hardware. Such IC's are (or were a decade ago)
available.

Cheers, Gene

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Received on Fri Jul 27 00:15:02 2012

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