[sdiy] Looking at the Digital Poly-Syngan

[Ian Smith]

Hi all,

It's been a while since my last post here. I've been busy with school and such. Anywho, I was poking around in the Music Building's library which is an odd little, out of the way, sort of room, and I found a book called "Electronic Music Synthesizers" by Delton Horn. It's a nice old 1980 book that has a section on what to look for in a synthesizer and the second section is all about DIY. Chapter 14 talks about this "Digital Poly-Syngan". It has a basic square-wave oscillator and 2 Frequency-doubling circuits that are quad XOR gates.... per key. It says to duplicate the circuit 12 times. So, for each key there's: a frequency knob, and a switch to switch in or out each of the 3 octaves. 

Now, I know that this is highly impractical if you want to have a standard 12 note equal tempered scale given the popularity of 1V/Octave and polyphonic keyboards and MIDI and such, but what if you want to have a keyboard that could be set up to have any number of notes in the scale you want? What would be a good way to make sure that the simple oscillators were as accurate as possible?

I'm sure there's going to be more questions about this later as I delve deeper into it, but that's it for now.

-Ian Smith
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