[sdiy] Additive Synthesis questions

[Aaron Lanterman]

On Apr 11, 2010, at 1:32 AM, David G. Dixon wrote:

> Hence, it would seem as if one could just about use unfiltered triangles to build up more complex waveforms with only minor error.  Plus, triangles are fairly easy to divide (simply rectify, double and shift), which means that one would only have to generate the odd multiples of any given frequency.
> 
> Of course, once you've got a bunch of tuned triangle waves, it's pretty trivial to shape them into sines...

I think the Synergy gave you the option of using triangle waves instead of signs (IIRC, I could be mixing that up with something else).

The Buchla 148 harmonic generator creates a fundamental triangle wave, and then goes through a bunch of contortions to shape that into the remaining 9 harmonics, in triangle form. Each of those 10 is shoved through a double-diode-FET-type triangle-to-sine shaper. The results are definitely far from pure, which winds up being far more interesting to work with in a Buchlaish context than "pure" sign waves.

- Aaron