[sdiy] various scales for a Midi-to-CV ??

harrybissell at copper.net harrybissell at copper.net
Thu May 3 18:26:31 CEST 2007

Are you talking about "tunings / temperment" or "scales"

Temperment is the actual frquencies used...

"Pythagorean tuning" uses whole number ratios related to the
harmonic series i.e. a fifth is a 3/2 frequency ratio

"Equal Temperment" has modified the frequency of the fifth (etc)
to permit playing in ~any~ key

Some of the Arabic tunings you mentioned have non-western intervals...

Scales, on the other hand... are selections from the available
pitches. Things like "major", "minor" etc have different half /
whole steps.

Assuming you want 'temperment' you could make up an offset table. Rev
Prophet V allowed you to use the twelve knobs in the center of the
to tweak the twelve notes +/- a small amount (one half strp iirc).

If you want to make 'scales' I'd use a MIDI-CV converter driving a 
programmable A/D - D/A such as the Wiard-Blacet MiniWave.

I've done #2, I like it a lot

H^) harry

>---- Original Message ----
>From: usenet at teply.info
>To: Synth-diy at synth-diy.org
>Subject: RE: [sdiy] various scales for a Midi-to-CV ??
>Date: Thu, 03 May 2007 18:07:43 +0200
>>hiya Synth folks,
>>I'm currently thinking about some sort of converter from MIDI data
>>Control Voltages. What i'd really love to achieve is the possibility
>>have this converter to respond to a selection of different scales.
>>that matter, there are a couple of scales around for any given base
>>tone. So in a clean tune (as opposed to a well-tempered tune) an A
>>is a tad different from an G sharp frequency-wise.
>>What i'd like to know is whether or not this is even worth the
>hassle of
>>computing all those frequencies with those VCO circuits around.
>>The background on my thinking is as follows: I'd like to be able to
>>a couple of different scales with my synth. Not necessarily all
>>  scales, but at least some sort of selection among all the scales
>>around like, say, Dur and Moll scales as well as some arabian
>>all, those tuned to clean base notes like G sharp or B Flat or
>>like that.
>>What do you guys think about that??
>>Synth-diy mailing list
>>Synth-diy at synth-diy.org

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