Archive of the former Yahoo!Groups mailing list: Korg Poly800/EX800 Users

Hi Michael,

On Friday 16 January 2009, Michael Hawkins wrote:
> I've done an analysis of the code that sets up the envelopes. The
> Poly-800 CPU is not fast enough to recalculate the envelope in real
> time according to velocity value and adjust any envelope parameter
> in a proportional way. If we were to try to do such a thing there
> would be a noticeable delay between hitting a key and hearing the
> note sound (and this is an ongoing challenge that I've faced
> through this entire project).
>
> So the only option is to use the same sort of set up as I used with
> the sustain pedal operation. If the sustain pedal is down then the
> decay and release values are increased by an offset value that is
> set by extended parameter 74. When you set the extended parameter,
> the Poly does all of the envelope recalculations right there and
> then and creates a second set of real time operating variables for
> the envelope generator to copy and use in real time at note on
> onset. At the moment, the only variables in the envelope data set
> that are being adjusted are decay and release. The rest are being
> copied from the original envelope data set to the secondary data
> set. But we can indeed adjust the other envelope parameters
> according to our whims.
[...]

I believe you can do significantly better for the velocity stuff than
just switching between parameter sets. Start the envelope right away
with the standard parameter set (which if I read you correctly
entails copying the pre-computed parameters to some place in RAM that
is exclusive for that voice). Then iterate a correction on that
parameter set each time you update that voice. The first portion of
the attack may not be overly accurate, but you should be able to end
up with a correctly scaled envelope overall.



Achim.
--
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk]>+

SD adaptation for Waldorf rackAttack V1.04R1:
http://Synth.Stromeko.net/Downloads.html#WaldorfSDada