Folium is an FM synthesizer that locks its oscillator ratios to the intervals of any tuning system, and gives you the tools to rhythmically glide, cut, and morph between the sounds it generates. It can sound harmonically consonant in any tuning, and harsh and clangorous when needed.
The idea for Folium centers around this late night thought I had: most synthesizers treat a scale as a pitch chart.
What if a synth treated it as a material?
What if when I loaded up a tuning, the whole instrument adjusted to it, beyond just its pitch?
A sinewave carrier, a frequency modulator (FM), and a Buchla style wavefolder.
FM ratios are derived from a tuning (via MTS-ESP or Scala files). You can pick up to 8 ratios and load them into the oscillator.
Simple integer ratios (like 3:2) ring consonantly, like bells. Higher ratios (16:9) turn the sound metallic and complex.
Drag a range bar directly onto the FM Ratio slider or onto the Wavefolder (shown above), and an LFO instantly sweeps inside it.
The same dual LFOs are also mapped onto Folium's Filters, with one knob instantly applying modulation to the control.
The thought behind these mappings: modulate quickly, in a gently organic way, like a breeze.
Two LFOs, ten useful shapes each. Run free, or synced up with your DAW.
Two filters in series, with four selectable modes each. A standard dual SVF filter, so far.
Here's the twist. Load a tuning, click the CUT button (being refined in v1.04), and the filter cutoff snaps to harmonics of the note you play, per voice.
Now the filter behaves like a resonator tuned to the loaded scale, not just a tone knob.
Each motion lane moves a target knob up and down from where you set it.
Tie two steps and the value glides between them, like a TB 303. Offsets, steps, and rates are all morphable too.
It's got 6 sliders stacked in signal order.
Press A. Change everything. Press B. One crossfader now moves Folium's controls between two complete patches.
Every position between A and B is a sound you didn't manually program.
Automate it by hand (patch scratching, anyone?), or point a motion lane at it.
Five dotted lines: oscillator, filter, envelope, LFO, motion. Each line seeds its own control group with a variation.
Useful, and good fun, for finding a place to morph your patch toward.
Folium.
In Early Access for Mac and Windows.