TONE WHEEL OR ELECTRONICS

[dave.amels@sfnet.com]

H >        On the down side of things, tone wheel generation  does
H >not produce an even tempered scale.  THE NEAT THING SOUND WISE is that
H >every note is absolutly phase locked - ZERO beat frequencys -VERY impo
H >and even more so when played through a leslie on fast speed. I used se
H >keyboards when designing the PRO-3 and all except my BELOVED A100 or a
H >othr tone wheel intrument had varying amouts of beat, especially 
H >noticeable on upper fifth and thirds. I remember someone on this list 
H > commenting about this on the XB-2 rencently.

A tone wheel generator only produces harmonics derived from the equally 
tempered scale.  Voice based synthesizers in general produce harmonics 
derived from the natural scale.  These harmonics are phase locked in 
frequency to the fundamental and beat against other notes of the equally 
tempered scale.

The Voce "V3" derives its harmonics only from the equally tempered scale. 
This is the same way the B-3 works.  The tone wheel generator is 
particularly suited for digital implementation because all of the tones 
are related by integers.  There is an integer number of teeth on the drive 
shaft gears, on the driven tone wheel gears, and the tone wheels.  There 
is, however, a significant amount of wow and flutter due to gear backlash 
and the non-constant torque output of the synchronous motor.

More about the fun wheely world we live in to soon follow,

/Dave








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