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Subject: Speed Modulation

From: "Max Fazio" <faxiomas@...>
Date: 2006-01-22

Hi all
This is especially for Juergen.
I've been happy to read a nice discovery you made about the differences between amount and speed modulation in the CS80, I refer to your message on the Analogue Heaven board of October 16th, 2003;
Quoting
> You never stop learning - last night I read a CS-80 review at
> www.amazona.de , and suddenly learned that the smaller CS-synths
> are missing another fine detail of the CS-80: Sub Osc (LFO) speed
> modulation via aftertouch!
>
> Surprised that I never had noticed this before, a question
> was immediatly arising: The CS-80 has polyphonic aftertouch, but
> there is only one Sub Oscillator. So the CS-80 must also emulate
> monophonic aftertouch internally. I consulted the schematics, and
> found that there is in fact a set of diodes which creates the
> ∗maximum∗ of all individual pressure sensors, and uses this to
> control the LFO speed. As expected.
>
> But there's more, and this is where it may become interesting:
> The diodes cause a voltage drop of approx. 0.5V, and there is
> no compensation circuit for this. So I expect the LFO speed
> modulation to come ∗later∗ (at a higher threshold) than VCF / VCA
> modulation when you gradually increase the pressure on a key.
> This would allow some brilliance and volume modulation by
> aftertouch without LFO speed modulation at low pressure
> values, and LFO speed modulation joining in at higher pressure
> values. Which would be another very sensible choice for a great
> performance-type instrument.
>
> Can anybody confirm (or correct) this behavior?
>
> Now I know another mod I have to do for my CS-50 (;->)
>
> JH.


End of quote.
So what do you mean when you talk about the maximum number of pressure sensors involved with the Speed trigger of S-O? and what about the % of pressure that allows the trigger of the speed?
Thx fr your reply
M

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