An expressive multi-timbral polyphonic synth with ‘wavefolding’.

It’s a MIDI-controlled synth with 5 voice polyphony built from simple sine oscillators, but the trick here is that each voice is built from two oscillators that are multiplied (Audio Multiplier) and then PWM’d, creating lovely wavefolder-like overtones and octave-shifts. The 2nd oscillator of a voice can be toggled to a few fixed intervals (unison, 1oct, 2oct, 5th, 1oct+5th) offering a few different timbral flavours.
There’s a Stereo Spread and reverb for added ambience.
It’s a nice little MIDI synth that can do some lovely xylophone-ish metallic sounds or crystalline ambient pads, and you can morph through the timbre with the Mod Wheel.

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[OVERVIEW]
-Input/Output: Stereo input (goes only through the reverb), Stereo out
-CPU load: Around 102%
-Build: Initial version built on ZEBU with firmware 2.80
-MIDI: All MIDI related modules (in PEACH colour) are on the 3rd page marked MIDI. I use channel 10 and if controls are set to CC’s I use CC 21/36 (see CONTROLS section for details).
-CV Inputs: Unused.
-CV Inputs: Unused.

[REVISIONS]
1.0: Initial patch.

[CONTROLS]
All the main controls are on PAGE0 and are labeled and starred (see below for a “Picture Manual” in the comments). The Stereo Output module with gain parameter is on PAGE1.

AMP VEL OFF toggle (turns off velocity for amp only; velocity is still routed to timbre modulation depth)
ATTACK / DECAY / SUSTAIN / RELEASE (speaks for itself)

TREMOLO RATE / TREMOLO DEPTH (speaks for itself)
TREM ON-OFF (toggles tremolo on/off; this is the blinking LED, doubles as the rate indicator)

TIMBRE TYPE toggle (scrolls through 5 timbre types; unison, 1oct, 2oct, 5th, 1oct+5th)
TIMBRE (acts like a waveshaping control; Mod Wheel is routed here via MIDI CC1)
TIMBRE MOD ENV (envelope modulation of the TIMBRE value; velocity and pressure sensitive)
REVERB (macro control for reverb time and mix; goes to full wet)
NOISE (fast, random pitch modulation)

ZOIA stompswitches = Unused.
ZEBU LEFT / RIGHT buttons = Unused.

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[PATCH STRUCTURE]
This patch all revolves around a trick I recently discovered; by sending one oscillator to BOTH inputs of an Audio Multiply you get a sound one octave up from the root pitch (works only for triangle or sine). Then if you change the pulse width of the oscillator, that octave overtone dissolves and ‘morphs’ back to the root pitch, with a whole bunch of cool mixtures in between. If you modulate the pulse width, it can sound almost like wavefolding!

Because Audio Multiply modules are low CPU cost, this is a great way to get more complex sounds out of a low-cost voice (it’s similar to using one oscillator into a VCA and then back into its own FM input; simple but effective). Here I’ve expanded it a little by using TWO oscillators and adding tuning offset options for the second one: it can be unison (so same as having one oscillator into an audio multiply), or 1 or 2 octaves up (giving some blended flavours of octave overtones), or a 5th or 1oct+5th up (giving some weirder, more atonal(?) timbres).

I’ve used this trick for some generative patches recently, but for my current setup I wanted to have some more MIDI controlled synth patches, so I made this patch: just a straightforward MIDI keyboard controlled synth, 5 voice polyphony, stereo spread and a big reverb. There’s a full ADSR envelope, Velocity to the amplitude can be bypassed, and there’s a fun Tremolo which goes well with the more pad-like sounds it makes. There’s also NOISE modulation (which is fast, random modulation of oscillator pitch) to give the sound some fuzzy edges, and lastly sounds go through a Stereo Spread and Reverb Lite module.

Now, to make the most out of this ‘wavefolding’ thing, I’ve routed the Mod Wheel to the TIMBRE value, and there are can also route velocity sensitive envelope modulation to it (T. MOD ENV), which allow some very expressive sounds: play soft = clean octave up bell-like sine tones, play hard = more low end and more complex overtones. Settings of TIMBRE and T. MOD ENV are very interactive.
MIDI Pressure (‘aftertouch’) is routed to the T. MOD ENV multiplier module, so it can increase that effect even further.

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[TIPS/TRICKS]
>>> This is just a nice, gentle, moody synth that sounds great in the middle/higher registers. It also does bigger chords quite well.
>>> Give it a nice arpeggio or simple sequence, then slowly turn the Mod Wheel to change the timbre, and it’ll gently morph into all sorts of nice overtones!

[THOUGHTS/IDEAS/PLANS]
No plans for this one; it’s a nice synth patch that I’m using regularly now. Maybe I’ll find something to improve!
If there’s any bugs/questions/remarks/requests or suggestions for improvement, please let me know!
Enjoy!

(Image: Witchoria)