[sdiy] 'equally tempered' vco

[Needham, Alan]

|-----Original Message-----
|From: synth-diy-bounces at dropmix.xs4all.nl
| [mailto:synth-diy-bounces at dropmix.xs4all.nl]
| On Behalf Of Simon Brouwer
|Sent: 24 February 2010 23:26
|Cc: Synth DIY
|Subject: Re: [sdiy] 'equally tempered' vco
|
|Laurie Biddulph schreef:
|> Exactly...
|>
|> The VCO has 3 basic sections:-
|> 1) front-end mixer
|> 2) core oscillator
|> 3) wave shapers
|>
|> The front-end mixer has been tailored to a 1V/Octave range
|>and this, I believe, makes it equally tempered. Replacing/
|>modifying this front end would allow other temperaments to be
|>catered for if I am not wrong.
|
|That is true as long as all semitone intervals correspond to
|the same voltage difference of 1/12 V. But there is no reason
|why you could not use a controller assigning a different
|selection of control voltages to the notes in the octave.
|There is nothing "inherent" in the ASM-1 VCO that prevents you
|from thus using e.g. Pythagorean instead of equally tempered
|tuning.
|
|-- 
|Vriendelijke groet, 
|Simon Brouwer.

Whilst I agree about the controller dictating tuning rather than the
oscillator, I do think that the above implies too strongly that the VCO
must be v/oct.
This is a falsehood, a v/Hz oscillator can just as easily be used for
equal tempered, Pythagorean, 5-tone, whatever; as long as the controller
is set up accordingly. The ETI 4600 (for example) uses linear
oscillators and its keyboard controller allows each note of the octave
to be adjusted to your desire.
Thus, my v/Hz oscillators can also be described as equal-tempered.

Alan.


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