Quad Wavetable Oscillator with Sub Octaves


Qwoso is a 26HP quad oscillator for the Eurorack synthesizer format, with each voice having a main wavetable output and a Sub output. This oscillator has a somewhat gritty, characterful sound and was created with a few primary goals in mind:

- To make it easy to experiment with harmony in modular, without having to spend lots of time tuning and retuning - to this end, the Note knobs and pitch CV inputs are quantized to semitones, but continuous pitch bends, vibrato, and subtle detuning are still possible with the FM inputs and fine tune knobs.

- To have numerous harmonically complex, different-but-related, outputs available for percussion synthesis and for monster unison/drone/additive patches.

- To offer a large variety of sounds and possibilities, but with an immediate, knobby physical interface. No screen, no menus, no modal controls or button combos to remember, no cheat sheet necessary.

- All parameters can be voltage-controlled.

Each of the 4 voices has its own frequency and fine tune knobs, V/oct pitch CV input, FM input with attenuator, and a main output and sub octave output. Note CV inputs 1-4 are normalled together, so all voices can be controlled by one pitch source, turning Qwoso into an ultra-complex additive voice where different outputs can be tuned easily to harmonic intervals. If you need a voice to have no pitch input, you can connect your first pitch control to voice 2, etc. FM inputs 1-4 are similarly normalled, for vibrato or audio FM purposes.

There are three mix outputs: one for main outputs, one for sub outputs, and one with all 8 outputs mixed together to make patching easy.

The Wave knob and its CV input with attenuator control all voices simultaneously, with smooth interpolation between waves. The Poly Wave knob and CV input let you shift the waves for voices 2 through 4 farther from this base wave value, meaning that each of the 4 voices can have a different waveform if you choose. Modulating the Wave and Poly CVs with two un-synchronized LFOs makes for some cool evolving pads that never repeat quite the same.

Each voice has an associated sub-octave output. Unlike typical sub-octaves, Qwoso's subs can be a variety of different waveforms, including sine, pulse, saw, and several harmonically-rich wavetable-style waves. The Sub control also selects whether the sub-octave is two octaves down from the main out, one octave down, unison, or one octave up. The sub CV is not interpolated, so you can get discontinuous octave shifts and sharp rhythmic wave transitions sequencing this parameter.

There is a Glide time knob for portamento (turn down all the way to turn glide off completely), and a gate input to allow switching glide on and off with a gate or CV.

Further waveform modification comes via the bit crushing function, controlled by the Crush knob and CV input, which takes the waves from 8-bit down to 1-bit for more extreme griminess and added high frequencies.


CV Inputs:
V/oct pitch CV for each voice, quantized to semitones

FM for each voice, unquantized

Wave CV, global, smoothly interpolating

Poly Wave CV

Sub octave wave/octave select CV

Crush CV

Binary Inputs:

Glide on/off gate

Audio outputs:

Main outputs 1-4

Sub outputs 1-4

Main mix

Sub mix

All mix


Currrent draw:
Depth: 21mm
Reverse polarity power protection, full over/under voltage protection on all CV/gate inputs.
Header for the 8 outputs allows for future expander connection on your own DIY expanders.

Binary inputs trigger at a threshold level of ~1.5V and are conditioned to trigger reliably even from non-pulse waveforms.
CV inputs expect 0V-5V range.