Say ‘mod matrix ring mod patch’ three times fast.

I’ve wanted to make a ring mod patch for a while that exploits the changes made to oscillators, allowing for rates below the audio range. When used in a ring mod, these create a lush tremolo, with a hint of phasing (to my ears), and being able to move between the audio and the sub-audio creates a lot of interesting opportunities.

I’ve also been playing around with the idea of using a mod matrix approach to UI. So… Solaris, the patch that smashes those two together to (I think/hope) positive results.

There are four modulatable parameters: the ring mod frequency, the aliaser frequency (I added this because it complements a ring mod well and introduces some similar tonalities), the ring mod oscillator’s duty cycle, and the ring mod oscillator’s FM amount.

These are controlled by five modulation sources: LFO (with four shapes), envelope follower, sequencer, pitch-tracking, and expression pedal (or CV).

Using the mod matrix is simple: press the pushbutton beneath the parameter you want to control that corresponds to the mod source you want to control it with. The depth for the connection is set with the mod source controls.

The path signal path is stereo in input mode I, a standard ring mod. Mode II has a dual mono output and uses a monophonic input (left input) to ring mod against itself, producing interesting harmonics and changes in timbre. Mode III is also dual mono, and it uses both inputs and ring mods them against one another. The mode can be changed with the “Input mode” control; a UI button next to the control will change colors as you cycle through the modes. Oscillator controls are non-functional in modes II and III, but the aliaser remains a modulation destination.

Controls:

Left footswitch — tap tempo (the patch also accepts MIDI clock); on the second page are clock dividers for the sequencer and LFO which determine their rates based upon the tapped tempo (or MIDI clock)

Front page:

Across the top:

Mix — wet/dry mix

Input mode — selects input mode (see explanation above)

LPF frequency — a filter on the output for controlling some of the more unpleasant ring mod tones

Modulatable parameters: ring mod oscillator frequency, aliaser frequency, duty cycle (changes the timbre of audio rate ring mods and introduces different shapes to the sub-audio tremolo sounds), FM amount (changes the timbre of audio rate ring mods and introduces metallic sounds to the aub-audio tremolo)

Modulation sources: LFO, envelope follower, sequencer, pitch-tracking, exp pedal (or CV). Each control has a depth parameter (called “Key-tracking” with the pitch tracker, more in a second) that can be positive or negative.

Note: Pitch-tracking and expression control can only be applied to the oscillator frequency or the aliaser frequency.

LFO — there are four shapes, chosen by the shape control: random, square, triangle, and ramp. The rate is determined by a clock divider on the second page.

The LFO can be unipolar (it moves up and down from the parameter setting) or bipolar (it cycles through the parameter setting as a central point). When the LFO is bipolar positive and negative depths will produce the same result.

There is also a control called “LFO smoothing”: it affects all of the shapes and can be used to change the waveforms (note: this has an effect on depth), but I mostly placed it so you could produce slewed/sliding random LFO shapes, like a classic ring mod sound.

Envelope follower — there is a slew control to determine the rate of the rise and fall of the envelope follower. There is also a button that combines the envelope follower and LFO, letting you set the depth of the LFO based on how hard you play.

Sequencer — the sequencer module is on the second page. Blue track is for notes. Green track is for changing the sequencer length; place a gate on a step to shorten the sequencer.

The sequencer also has a portamento control.

Pitch-tracking — along with a portamento control, the pitch-tracking option has a controlled called “Key-tracking.” If you’ve used synthesizer before, this may be familiar, but it is a “depth control” that also determines how the notes played are tracked by the oscillator. It goes from -200% to +200% with 100%/true pitch-tracking corresponding to a value of .5000 (or A5).

Subtle variations in pitch-tracking can produce sort of wonky musical progressions; more dramatic ones become quickly atonal.

When used in the sub-audio range, this can produce a pitch-tracked tremolo that grows faster as you play higher notes (positive key-tracking) or grows slower as you play higher notes (negative key-tracking). That’s a lot of fun to play with.

Expression pedal — there is a portamento control for this as well, if you want to smooth out the response of an expression pedal.