Sliders galore

[Tony Allgood]

Doug wrote:  Did your 1986 prototype function well enough to produce
output?

No, my original Walsh oscillator just sat there, took a great deal of
current and did nothing. It had a 32 step envelope generator for each
Walsh output, but it was this that didn't work. Without this, it was
speachless. Now, my new one does work... very well actually. What does
it sound like? Difficult to say, since at the moment it is sitting on
the test bench, hooked up to an amp and CRO. Haven't yet got it hooked
up to a keyboard, VCA etc. You can make most of the standard VCO
waveforms, but you are at Nyquist's door here. Just like a sampler, you
will need to add a tracking filter to get rid of any high frequencies
beyond the highest Walsh frequency. However, some of these high
frequency components are actually very interesting.

At the moment only static waveforms can be set up, but the plan is to
make them dynamic. I don't think 31 ADSRs will be a good idea. You will
not be able to set up harmonic sweeps with the ADSR envelope. I am going
to go for a similar system to my first, ie programed envelopes set up by
the walsh sliders. That is a 31 step EG, bit like running a 31 step
analogue sequencer. Except that the step will be controlled by a voltage
rather than a clock. A merge idea is on the cards too, I am not too sure
how I am going to do this. I think a uProc is going to come out here.
But I may be able to do this with PWM.

>Is it just me, or does it seem like a single Walsh VCO ought to be able
to produce formant-like (as in human speech) output?

So far, my initial experiments have been very promising. Once you get
used to adding one Walsh to another, you can get some stunning results.
Very hard, almost sync'ed, sounds can easily created. Some of the Wals
even beat with each other at low frequencies. Very rich. Unlike additive
synthesis with sinusoids, adding more Wals can actually make for a less
rich tone. A sine wave needs quite a few wals to be added.

More later, when I have had more time to play more.

Regards,

Tony Allgood, Cumbria, UK

Rack mounted moog filter and the TB3030 SuperBassline projects:

http://aupe.phys.andrews.edu/diy_archive/schematics/oakley/