Now it's time to fatten the sound. The oscillator section of the SubTractor is very versatileit allows you to adjust the phase modulation ("phase mod" for short) of each oscillator.
Huh? Well, each SubTractor oscillator can create a second tonea copy of itselfbehind the scenes. When the SubTractor combines this copy with the original tone, it creates a new, third tone. This is not the same thing as having four more oscillators. Rather, it's a process called phase offset modulation. What does it do? Despite its complex-sounding name, this process is simply a powerful tone-shaping tool.
The Phase knobs control the amount of the phase offset's effect, and the three-way switch next to each oscillator activates the offset and sets its type. The O position has no modulation (fat), the position has some (fatter), and the X position has the most (fattest).
For starters, let's listen to how the phase mode controls affect the sound of just one oscillator.
To set phase mod characteristics
The SubTractor has a mode called ring modulation. Use it to get a brighter, more bell-like sound.
Ring modulation is like the X type of offset modulation, but instead of multiplying a signal by itself, ring modulation multiplies the Osc 1 and Osc 2 tones, creating difference and sum frequencies between the two oscillators.
There are no phase type controls for ring modulationit's either on or it's off.
To use ring modulation