[HAM] M3 with no sound----SOME COMMENTS

[Doug Brydges]

>
> From: <dd.davis at mindspring.com>
> Date: 2003/06/08 Sun PM 03:17:42 EST
> To: <hammond at zeni.net>
> Subject: Re: [HAM] M3 with no sound----SOME COMMENTS
>
> You guys are amazing!  And right on the mark.   The TWG is freed up now and finally spins silently.<

- - -ahhh, the smell of Hammond Oil in the room is a goooood one.


> Is it possible to explain to me what about the leslie is so synonomous with the B3?   I'm familier with the rotation, the dopler effect and so forth, but is the leslie amp that different that it colors the sound?  or is it the manipulation of the speaker output what does it?   I guess the easy answer is 'both'  but I was just curious.  And also, how does the leslie rotation (effect) differ from normal vibrato or tremelo?<

 - - - All speakers produce sound by using an electromagnetic coil which pushes and pulls a stiff cone at different speeds (frequencies or vps - vibrations per second) which then, in turn pushes against air in the atmosphere. It's the movement of air that is picked up by your ears as sound.

- - - A leslie cabinet uses a rotating horn on top of the driver (small high range speaker). This moves the 'sound' in circles (the doppler effect) at fast and slow speeds, depending on switch position. Low-end sound is manipulated by rotating a large baffle under the bass speaker cone and this has a similar effect... as the baffle rotates it blocks and un-blocks the sound with each full rotation. What really makes a good leslie cabinet do its wonder with the sound is that the upper horn and lower baffle have different 'ramp-up' speeds -  when you switch to fast from slow, the horn speeds up to fast rotation quicker than the baffle does and the resulting effect is what makes a Hammond sound 'waaayyy coool'.

In contrast, vibrato and percussion effects are put on the electrical signal BEFORE it gets to come out the speaker. They are manipulations of the electrical signal, while leslie action is a manipulation of the air as it is being moved by the speaker cones.

You can use a leslie on just about anything - not just a Hammond. I bought my first Leslie 147 new in 1974 and used it with an old, green & grey vinyl-covered, late 60s Gibson combo organ (still works today). Later on I used it with several synth boards. I sold the 147 in 1998 (regret it now) for just $600 Canadian (TrekII preamp included). I now use a much smaller, more portable Leslie 18 (18" speaker with rotating foam baffle and no high-end rotating horn) fed by a 200W keyboard amp when using the synth boards. I rigged a dpdt switch on the back of the M3 to by-pass the built-in speaker and direct the signal thru a 1/4" jack to the Leslie 18. Works fine.


> Should a Hammond (A, B, C or even my M) sound like the classic B sound if all were run through the same leslie?<

Not necessarily so simple. Each Hammond model has different tonal characteristics which are all dependent on the effect and signal control circuitry embedded in each organ's electronic components, keyboard contact wiring, drawbar ranges, etc.

For instance, an M3 can be made to have tonal characteristics very similar to a B3 by adding extra contacts in the key switch sections of both manuals in the upper ranges. Called adding 'foldback', this (I understand) adds more sound depth by adding more bottom'end tone to the upper notes on both manuals.

As I just noted in my last post, adding foldback to my M3 will be my next project.

Doug Brydges (keyrocks)
>
> Thanks.
> [ Deleted '----- Original Message -----' ]
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