[sdiy] Telharmonium motors, perhaps?

[john mahoney]

A TOG (top octave generator) can derive 12 pitches from one master
frequency, so I say that yes, one rotating disk could contain 12
optical pitch tracks, BUT... the numbers are not very encouraging.
Remember that we need high frequencies (we must accomodate the *top*
octave, after all). A turntable is way too slow.

Take a look at the TOG divisor ratios:
    http://www.organservice.com/crm/topdividers.htm#Fig6

Visualize a protractor and you can picture 360 divisions per circle.
One revolution = 1 cycle.

Enough rambling for now...
--
john


----- Original Message ----- 
From: "Glen" <mclilith at charter.net>
To: "Michael Baxter" <mab at cruzio.com>; "Gene Stopp" <gene at ixiacom.com>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, November 22, 2004 8:46 PM
Subject: RE: [sdiy] Telharmonium motors, perhaps?


> At 08:09 PM 11/22/04 , Michael Baxter wrote:
>
> >This then leads to a motor speed controller and phase-locked loop,
and
> >then eventually 12 motorized speed controllers for an
equal-tempered
> >octave, with 12-16 VCAs per voice ...
>
> I wonder if you would really have to use 12 motors? Perhaps you
could get
> more than one of the 12 notes of the scale on the same disk? If the
disk is
> larger, it would be easier to fit more notes on it. If you use
opaque
> printing with reflective sensors, you can also use printing on both
sides
> of the disc. If you could manage to cram all 12 notes of the scale
onto one
> disc, you would automatically guarantee that the unit would always
be in
> tune with itself, without the need of servos or PLLs. I wonder if a
special
> disc could be printed and adapted for a common vinyl record
turntable?  :)
>
> It would certainly be a cheap way to experiment with the concept,
and it
> might be of some research value, even if you eventually decide to do
> something far more elaborate.
>
>
> take care,
> Glen