User Guide

Chapter 22 EVB3 337
Crosstalk
The Hammond’s tone wheels are divided into compartments of four—with the same
key, but in different octaves. There are two tonewheels, four octaves apart, on each
rotating shaft. The signal of the Lower wheel contains a small amount of signal,
induced by the higher wheel, and vice versa. This crosstalk can be adjusted with the
Crosstalk slider. Note that crosstalk is only audible on certain wheels, avoiding rumble
when chords are played.
Random FM
If the tonewheel generator is clean, all frequencies are straight—meaning the
frequencies are even/in tune. The three-fold decoupling of the tonewheels—via
springs, flexible couplings and flywheels—is very effective, but can’t compensate for
irregularities that come with dirt and grease in the driving gear. This gradual build-up
of grime in the mechanism makes the revolution of the tonewheel assembly irregular
on its axis. This is transmitted to the tonewheels. The Random FM slider allows you to
simulate this effect.
Note: The effect only becomes audible in the higher frequency ranges.
Filter Age
The high frequency output signals of the B3’s tone wheel generators are filtered by
bandpass filters. The center frequency of these filters varies as the capacitors age. Filter
Age allows you to alter the center frequencies of the filters. This colors the sound of the
jitter applied by Random FM and the background noise resulting from leakage. (See
“Leakage” on page 336 and “Random FM” on page 337.) This parameter also influences
the intonation of the organ, if you use the pitch bender.
Click Parameters
The key contacts of electro-mechanical tonewheel organs tend to saw a little on the
busbar, introducing a short click sound. If any corrosion occurs to the key contacts or
busbar, this will increase the length, and level, of this click. This aspect of the B3’s
design causes irregular scratching noises (commonly referred to as keyclick), when
striking and releasing keys. Hammond fans like these clicking noises, as they introduce
a transient, percussive quality to the note. The EVB3 allows you to adjust the volume
and sound of the key click. The click sound is altered randomly, and independently,
from the click on and click off (release) volume settings.
Click parameters