Laptopia

[ian-s]

Here is more experimentation with decades old ideas, rhythm processed by Serge style wave multiplier (mid section) then completely gushed by grain-o-matic. The solo voice uses the 2nd order PLL from the source of uncertainty (Buchla) and yet another grain-o-matic. The cheap sampler piano chord effect came accidentally from an experiment with audio rate PWM.

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laptopic-Edit.mp3
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Lap.prf2
Description:	experimental G2 perf	Download (listen)
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[mosc]

[ian-s]

Thanks Howard

The Serge wave multiplier is in slot A VA, column 2. It simply consists of a SeqCtr and a rectifier. The SeqCtr is set up for half the transfer function and the rect mirrors the other half. The effect is blurred somewhat by the grain-o-matic in the VA. Change the output to 1-2 to bypass the grain effect. Its like distortion with a little PM, because the transfer function is static it works best with dynamic inputs.

http://www.musicsynthesizer.com/Circuitry/nlt.htm

The grain-o-matic in the FX section is like a pitch shifter module but uses much longer delay than the Clavia module giving time stretching or even backward type effects. It works by creating sine envelopes on 4 delay taps modulated by synchronised, variable slope ramps. I posted it a while ago in the FX section.

The source of uncertainty sub section is in slot C, it is based on the premise that summing noise directly into the integrator of a simple triangle oscillator behaves like a PLL, I cant seem to find the SynthDIY thread where I read this but the circuit consists of a home made triangle oscillator with noise injected at the integrator. A Schmitt trigger is formed by a comparator with feedback, the square wave output inverts the polarity of the ‘charge current’ producing the triangle. The end result is a source that varies from simple triangle to very random depending on the amount and colour of the noise.
Its only a very small part of the source of uncertainty and is not used in this way specifically in the original AFAIK.

[mosc]

Thanks, Ian. Very helpfull.

[cebec]

hi Ian. I'm trying to isolate the schmitt trigger from the source of uncertainty but i'm not sure i'm taking all of the right modules. could you patch a generic schmitt trigger i could drop into other patches? i really don't know how to go about patching one, myself.

[ian-s]

http://electro-music.com/forum/topic-6302.html

This is the building block the I extracted from the prf2.

If you are just after the schmitt trigger, it is just a comparator with feedback provided by a mixer.
A regular comparator (or compare module) will change state when the input voltage exceeds the threshold. The feedback provides hysteresis so that once the output goes high, the input voltage needs to go lower than the original trip point to change state.
A small amount of hysteresis is useful to reduce multiple triggers on noisy signals.

[cebec]

thanks!