From ozmusicman88@internode.on.net Thu Jan 24 17:19:38 2013
Subject:Re: Tremolo in scanner chorus/vibrato

I used to have a Hammond M100 and B3; I now have a Hammond XK3c and XK1, both of which have a tremolo parameter in the chorus/vibrato settings, but (by design) it only affects the vibrato, not the chorus.

Nowadays, the vibrato effect is heard much less frequently than the chorus effect, which is a highly characteristic part of the classic tonewheel sound, either alone or with the Leslie effect, the two effects interacting to produce an even richer modulation than either effect alone.

Because the chorus effect in the original tonewheel organs is achieved by combining the vibrato signal with the dry signal, vibrato (pitch modulation) and tremolo (amplitude modulation) are largely cancelled out, leaving mainly a smooth but rich "shimmer" or "purr", (primarily phase modulation).

Here are a couple of examples of the chorus effect that sound good to me.
http://www.youtube.com/watch?v=1y1lRjWFOSY
http://www.youtube.com/watch?v=YabuH0cShXo
http://www.youtube.com/watch?v=rT1w1Udhz7Q [0:00 - 0:55]
http://www.youtube.com/watch?v=PBWwRIAbv0Q [2:01 - 2:31]
http://www.youtube.com/watch?v=arR9Q41ISNM [0:10 - 0:40, 3:30 - 3:50]

To my ear, important parameters for the chorus effect in addition to modulation speed (normally 6.8 Hz) and depth would be the dry/vibrato mix (normally about equal) and the taper in the degree of the effect on high and low frequencies.

Keith H Clark wrote:
>There is negligible tremolo in a properly running c/v system....

donstavely wrote:
> I understand that the Hammond scanner chorus/vibrato has some unintentional tremolo in it, due to amplitude losses in the delay line. Does anyone know how much tremolo there is?....

> I have seen this tremolo effect listed as a parameter buried in the chorus/vibrato menus of some modern clones. Is this something that any of you have tweaked? If so, what is you opinion on its importance to either an "authentic" or a "most pleasing" chorus/vibrato sound?