OC-D2 is an octaver plug-in that generates a signal one and/or two octaves below the original.

It's based on the popular Boss OC-2 pedal, but with many more features and customizability far beyond what other octavers offer. It's unique from the Boss and other pedals, and other octaver plug-ins, in that it offers:

Controls to all the typically fixed values for low-pass filters
Both on oscillator outputs (changes tone from full square wave to pure sine, or anywhere in between) as well as on the detection circuit (which can fine-tune the accuracy of the octave-divider's tracking).
Option for two modes of operation: additive oscillators or phase-multiplier. The additive mode simply mixes in the octave down signals (via user-adjustable levels and wet/dry balance), whereas the phase-multiplier mode flips the phase of the key signal, following the state of the selected oscillator.
In additive mode, dynamics for the oscillators can be controlled either by a noise gate or an envelope follower, both keyed off the input signal. In phase-multiplier mode, the full dynamics of the key signal are retained.
Polarity Multiplier has two modes: A and B. Mode A (old version) flips the polarity of the key signal directly at the positive zero-crossings. This abrupt change in direction causes additional harmonics, and results in a brassy tone (although can be filtered out). Mode B is a more complex circuit, and a more accurate simulation of the original Boss OC-2 pedal. A different version of a flipper circuit is used for this mode. Here, the key signal is DC-offset so that negative peaks sit at zero amplitude. The signal is then flipped in polarity when the peaks hit zero. Since the peaks/crests of the sine(ish) waves of the filtered key signal slow their rate of change at the point where they begin to change direction, crossing at this point instead of at the quick zero-crossing of the original waveform results in smoother transitions with less harmonics.
A DC-offset switch corrects the input signal to improve tracking on rectified or offset signals.
A scope displays both the key signal and the output signal, so the use can see how the plug-in is operating, and help identify what controls need to be adjusted in order to track more accurately or produce the intended sound. Includes a "tuning" control to affect the zoom ratio.
"Listen" radio buttons allow the user to tap the audio at any stage to hear what's happening behind the scenes, and bypass certain sections if desired.
Many users of the Boss OC-2 pedal seek to add a hardware modification that disables the output filter and dynamics sections in order to produce a more synth-like tone. This plug-in has the capability to easily reproduce this mod, by adjusting only a few parameters. Included are some presets that run through the capabilities of the plug-in.