From tande.adamson@btinternet.com Fri Aug 23 17:00:36 2002
Subject:Re: Leslie Vs Motion Sound

--- In CloneWheel@y..., Bruce Wahler wrote:
> Hi Galen,
>
> >Is the weight of a Leslie's wooden shell high enough of a
percentage of the
> >total weight to entice engineers to consider leaving the Leslie's
> >traditional size and shape as-is and concentrate instead on a
lightweight
> >shell material? ...Or, is the wood material itself as essential
to "the
> >sound" as the other, previously discussed factors?
>
> >Is the weight of a Leslie's wooden shell high enough of a
percentage of the
> >total weight to entice engineers to consider leaving the Leslie's
> >traditional size and shape as-is and concentrate instead on a
lightweight
> >shell material? ...Or, is the wood material itself as essential
to "the
> >sound" as the other, previously discussed factors?
>
> The wood is part of the sound, as well as a major reason why the
Leslie doesn't "walk" around the stage from vibrations when running
on tremolo! :

This is perhaps going to be a duck for cover reply post.

But as I understand it, it really isn't essential at all to have the
traditional material involved in the production of sound, unless the
traditional material actually vibrates sufficiently enough to form
part of the character of the sound, ( ie. if it acts as a sounding
board )
If the traditional material is rigid enough not to add significant
extra harmonic distortion, then same thickness plexiglass will do
just fine. Sound relies to a great extent on the thickness of the
material at the aperture from which it sends out the vibrations.
Metal pipes do not produce a thinner sound than wooden pipes because
of the materials from which they are constructed per se, but produce
their characteristic differences because of the thickness of the
materials at the exit points where the sound vibrations meet the
outside air.
Hi Fi Loudspeaker manufacturers go to great lengths to ensure that
their wooden box/or MDF constructions don't interfere with the sound
generated by the cone. Speakers are surface mounted for this purpose
so that the thickness of the cabinet does not impose tonal changes on
the Hi Fi sound it is built to reproduce.
Opposite to this, the thickness of the wood, where the louvres are on
the Leslie, has a decided effect on the overall tone. Obviously, to
make a metal Leslie cabinet with the same thickness metal would
produce a pretty heavy cabinet, but conversely if a same thickness
but light-weight inert and rigid material could be used this would do
as well.
Thomas.