From bruce@ashbysolutions.com Tue Jul 11 21:09:12 2006
Subject:Re: Kind of OT: to diffuse or not to diffuse ?

Hi Harvey,

Thanks for setting the record straight. I for one did not know that the 30A had a top grille. Live and learn!

Regards,

-BW (who will henceforth refer to the Leslie's "reflectors")

--
Bruce Wahler
Design Consultant
Ashby Solutions™ http://consult.ashbysolutions.com
978.386.7389 voice/fax
bruce@ashbysolutions.com

At 11:19 PM 7/11/2006 -0400, you wrote:
><< The way I understand the history of the diffusers goes something like
>this: Early Leslies with treble horns were in open air and did not have
>diffusers. When an enclosure was built around the horn in later Leslies, the
>diffusers were added. >>
>
>REFLECTORS!! No Leslie EVER had "diffusers." Nor did they have "deflectors."
>The small conical inserts in the ends of the rotary horn are, and always
>have always been reflectors.
>
>The original Leslie 30A (1940) had an "open top." Sound from the handmade
>papier mâché horn was reflected around the inside of the cabinet and reflected
>out the top. The first Leslie cabinet with louvers was the 31A introduced in
>1946 after WW2. Eliminating the open top got rid the fragile grill cloth on
>top, but it also eliminated the reflected horn sound. Now the horn produced a
>direct blast of sound every time it came around. To compensate for the
>louvers Don Leslie added reflectors to the horn itself.
>
>You get more "bite" and better coverage when you remove the reflectors but
>you also kill that upper midrange "sweetness" that's so much a part of the
>Leslie sound. The old man did a lot of things right 60 years ago, this was one
>of them.
>
>Harvey Olsen
>
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