Juergen.Haible at nbgm.siemens.de
Mon Jun 23 12:03:38 CEST 1997
> i'm planning to build a machine which will produce sounds
> evolving and morphing one into another (pardon my english).
> than have a usual saw/pulse/tri alternative, i'd like to make
> which would continuously morph between these. so far, the only
> comes to my mind is to feed an EG with a pulse. in theory,
i'll have six
> parameters (pitch, pw, adsr) to play with, but will this work
> world? will i have to make my own egs (oh, no!) or it's
> existing chips?
Oh yes, you can make your own EGs ! (;->)
First, you could use a static crossfading like my "Interpolating
which works very nicely at audio rate. (Piecewise linear - PWL
But I really like your idea as well, and what you need is *not* a full
circuit, but only a very simple "1-stage envelope" which is reprogrammed
with a new asymptode CV ("sustain") and time CV ("decay") for each step.
This "envelope" would not be more than a 1-pole VCF, i.e. 1 OTA plus
a few discrete devices. The two CVs would be updated with a simple
shift register (sequencer). You'd want to have the time CV input
with a keyboard tracking function included.
The whole thing would not be as predictable as the PWL solution, but
may be a feature. You can also chosse between linear and exponential
slopes by either using a straight VCF or a slew limiter circuit for the
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