The block has 2 additive based oscillators: Oscillators 1 & Oscillator 2. Oscillator 2 is on the left and Oscillator 1 is on the right. Each partial of the additive oscillator can be FM modulated from the corresponding partial of the other oscillator, using DX7 style ‘phase modulation’. This Modulation is controlled using the 2 ‘FM’ knobs. The partials are basically sine-wave oscillators, one partial for each harmonic of the sound (although partials are normally sine waveforms, you can change the partial waveform from sine to another waveform using the PARTIAL WAVE control).

The FM modulation works like this:

Oscillator 1   Oscillator 2

Partial 1  —> Partial 1

Partial 2  —> Partial 2

Partial 3  —> Partial 3

Partial 4  —> Partial 4

Partial 5  —> Partial 5

etc...

Each oscillator has its own FM knob so you can modulate in both directions: Oscillator 1 from Oscillator 2 as well as Oscillator 2 from Oscillator 1. If you turn up both FM knobs you will get some circular feedback and so will hear more noise and randomness.

Oscillator 1’s FM knob has a 4 way switch under it which let’s you select from 4 types of modulation:

• FM = Regular DX7 style FM. Each partial of Oscillator 2 modulates the phase of each partial of Oscillator 1.
• AM = Amplitude Modulation. Each partial of Oscillator 2 modulates the amplitude of each partial of Oscillator 1.
• RM = Ring Modulation. Each partial of Oscillator 2 ring modulates (multiplies the output value) of each partial of Oscillator 1.
• SH = Sample & Hold. Each partial of Oscillator 2 sample & holds each partial of Oscillator 1 (the sample & holding occurs at zero crossings of Oscillator 2) .

Modulation from Oscillator 1 to Oscillator 2 is fixed to using FM (Regular DX7 style phase modulation).

Each oscillator has filter controls for CUTOFF and RESONANCE. The filter is also additive-based, it is processed within the additive engine. The filters work simply by attenuating the amplitude of higher frequency partials and the resonance control boosts partials around the cutoff frequency, thereby simulating the resonance control of an analog filter. The shape of the filter is controlled using the FILTER SHAPE control (High Pass, Band Pass, Low Pass Notch, Comb, Phaser etc).

The basic timbre of each oscillator is set using its WAVEFORM control. This control takes a waveform from a wavetable and extracts the phase and amplitude of the waveforms to control each partial of the oscillator. So for example if you select the sine-wave shape in the wavetable, the basic sine will be just the 1st (fundamental) partial with maximum amplitude and all higher partials will have an amplitude of zero, the sawtooth shape will have all partials audible with their volume decreasing evenly as the partials get higher. You can load your own wavetables (Serum format, of any length) into either oscillator.

There are input ports for each oscillator. The input is harmonically analysed, without latency, to determine the amplitude of the partials. The pitch of the input is also tracked and this is assigned to control the oscillator pitch (by setting the PITCH MODE to INPUT (ear icon)), when the re-synthesis set up right, the output of the oscillator can quite accurately match the input (with just a few cool sounding artefacts).