[sdiy] Synthex Oscillator

[rsdio at audiobanshee.com]

By the way, this 8-to-1 mux would be very inefficient in a fully polyphonic synthesizer. It's only because the Synthex is an 8-voice that this makes sense. In a fully polyphonic synthesizer, all 8 inputs to the mux might be used if the right keys are played. Of course, a fully polyphonic synth would have serious issues due to the number of VCF circuits needed, unless it were paraphonic.

I mention this in case some of the ideas in the Synthex might be useful for a string synth or other fully polyphonic synth. The dividers and counters could be shared among multiple voices, whereas in an 8-voice like the Synthex, there's no predicting whether the other notes would be related by simple octave intervals, and thus each voice needs an entirely independent set of counters/dividers.

Brian


On Jul 8, 2017, at 1:16 AM, Tom Wiltshire <tom at electricdruid.net> wrote:
> On the right, in the blue box, is another counter, used to determine the octave. This is pretty straight-forward. It's  a binary counter followed by a 8-to-1 multiplexer to select the required octave. The highest octave is fed directly from the clock. Ok, *almost* directly. And here's where things get interesting.
>