There is a new release of the Axioma plugin with the addition of the Rhodonea module. It is a VCO based on the Rose curves. It follows a similar approach as the one used in polygonal synthesis (or an “inverted Lissajous”), where the curves in polar coordinates define the shape of the oscillator waves. Two outputs are generated, one for each cartesian axis. The ratio between parameters n and d define the harmonics. The parameter a can be used to smooth the curves and balance the level between a pure tone (set by the pitch) and the harmonics. The angle parameter can be used to rotate the polar curves leading to some phase modulation in the output waves.
Somewhat interesting is that I got similar results by ring modding the (x,y) pair from a quadrature sine/cosine oscillator with another sine at a rational multiple of the frequency of the first. I suspect if I wanted to spend some time doing analytic geometry, I could prove the equivalence. Still, this puts it all in one nice box for simplification sake. Good on ya!
I immediately thought of my old Mac LC and the After Dark screensaver’s Rose module, written by Ben Haller (Stick Software)… I am not nostalgic for the hardware of the early 90s, but the zeitgeist of independent software devs then? Sure, in a sense- that’s what appeals to me with the Rack community- that same creative, exploratory, not-corporatized-yet feeling.
Hello Werner,
I have just been experimenting with your Rhodonea module and using Sckitam’s 2D Rotation, 2D Affine and Polygonal VCO and Bogaudio’s 8FO. I have created something a kin to the Polygogo Eurorack style module. Any further developments, you may add are quite welcome.
Thanks, glad I could be of service! The Polygogo does produce rather great tones! So I am sure that you can adapt your Rhodonea to produce a wider range. A great module may become greater.
