From mate_stubb@yahoo.com Sat Jan 08 09:20:20 2005
Subject:Re: Motion Sound: matching upper/lower rotor speed


I'll bet that the opposite direction spin was a (happy?) accident. The
very first leslie I owned (model 45) had single speed motors, and in
that one the rotor's motor hung downward, not upside down as was later
the case when the slow motor was tacked on. The rotor and horn on that
45 rotated in the same direction.

I'll bet that when slow motors were added, and the additional height
of the motor stack bumped into the amp, the bottom motor stack was
simply turned over without thought to the change in rotational direction.

There's a story floating around in Leslie lore about a later model
Leslie that didn't sound quite right to somebody's discerning ears,
and when they looked at it they saw that the rotor and horn were
rotating in the same direction because the one motor's pole pieces had
been accidentally assembled backwards.

So at least by that point, the rotational differences had become a
prized part of the sound. I wish I could remember the details of that
tale better.

Moe

>
> The opposite direction of the Leslie rotors was not a design flaw,
> that's the contrast! That makes the Dopler Effect even more audible.
> The reason they rotate opposite is because the top rotor motor is
> placed underneath the rotor and the bottom one is upside down, above
> the bottom rotor. Therefore, they spin in opposite directions.
> Rick