3. Oscillator Part 2

  So I have one working oscillator.  Nice but now what?  In my research I had learned that one of the things that made the old analog synths sound so nice was having two oscillators.  The slight detuning between the two oscillator tones mixed together creates a nice movement (can also be emulated with a chorus effect) and also opens up possibilities like cross modulation (modulating one oscillators frequency with the other oscillator, a basic form of FM synthesis) and sync.  So next I just built another copy of the oscillator using the same circuit as the first one.  I hooked them both up, got them in tune with each other and yes!  That was THE SOUND I was looking for.

  Now I was getting excited.  This was my first realization that I was really on to something, and that this could turn into something really cool.  A pretty small step (and short post) but to me it was an important one as it was the first key point that took me from "lets see what happens" to "this is worth putting more time/effort/money into".

  Next step?  Lets start getting these oscillators under control - the midi controller.


  1. Hi,

    Great work, I try to build a 8 Voice polyphonic too. Did you implement an auto tune function?


    1. Not quite. The voice boards can feed back the VCO outputs to the controller board, but I didn't implement the muxing to route them to the microcontoller. I was more interested in the tone generation than automated features, but I may do a more advanced controller later.