A self-playing, mildly distorted organ-inspired chord machine that outputs accompanying melodic pitch CV.

This is a self-playing patch that makes chords and sounds a bit like an organ. It’s built from four sine oscillators and there’s some mild (or not) overdrive after they are summed.
The chords change like a Krell-patch; higher notes/chords last shorter, lower notes/chords last longer. Chord intervals are determined by adding a CV offset value to the 2nd, 3rd and 4th voices, tweaked in such a way that they are always musical (and sometimes a little bit uneasy), without being simply random. The SIZE control gradually blends in more voices for a bigger chord feeling, and there’s some filtering, noisy modulation and tape vibrato options.

The organ voices eat up all the CPU so there’s no more room for proper lead voices, but there’s a pitch CV output (on ZEBU) that can provide a very nice accompanying melody for an external synth/oscillator. It’s rapidly scanning through the notes of the current chord and samples them to make the melody, but because of the ratio between sampling rate and scanning rate, all kinds of cool patterns emerge. The trigger CV output only triggers when the pitch changes, so that gives it a very ‘human’ musical character. So, just plug in a Rings or another nice plucky oscillator, wiggle the MELODY LFO and find the sweet spots!

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[OVERVIEW]
-Input/Output: Mono input, Stereo out
-CPU load: Around 100%
-Build: Initial version built with firmware 2.70
-MIDI: Controls are NOT YET set to CCs (I normally use channels 21/36, see CONTROLS section for
details).
-CV Inputs:
1) Size
2) Spread
3) LPF
4) HPF
-CV Outputs:
1) Root Pitch (1V/oct)
2) Intensity
3) Melody Pitch (1V/oct)
4) Melody Trig

[REVISIONS]
1.0: Initial patch.

[CONTROLS]
There’s not really a need for controls, but I’ve added some macro-controls on PAGE0 (see below for a “Picture Manual” in the comments). The Stereo Output module with gain parameter and the Reverb module are found on PAGE1.

SIZE (sets the chord size from 1 to 4 voices)
INTERFERENCE (sets the amount of noisy modulation and dropouts)
SPREAD (sets the spread between lowest and highest notes)
WOBBLE (sets the amount of unstable pitch vibrato)
LPF / HPF (Low and high pass filters)
MELODY LFO (sets the rate of the melody CV pitch)
DIRT (sets distortion and grit of the oscillators)

Additional controls on PAGE1:
CHORD LFO (speed of chord changes and duration)
TRANSPOSE (tuning of all voices and pitch outputs)

ZEBU LEFT button = Toggle the chord voices on/off
ZEBU RIGHT button = Toggles the melody trigger CV output on/off
ZOIA stompswitches = Unused.

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[TIPS/TRICKS]
>>> Use this patch as part of a bigger Eurorack patch and let it control other oscillators via the Pitch and Trig CV outputs, and use the Intensity CV output to modulate things.
>>> Or just sit back and enjoy a self playing chord machine. Don’t forget to slowly modulate the SIZE or SPREAD, or the filters.

[THOUGHTS/IDEAS/PLANS]
This patch is done, no future plans.

If there’s any bugs/questions/remarks/requests or suggestions for improvement, please let me know!
Enjoy!

(Image: Katarzyna Mrozewska)