pH ～ a Humus organism

An FM synthesizer with four engines: a six-operator engine that reads DX7 .syx banks, and emulations of the OPN2, OPM and OPL3 chips.

Inlets
MIDI	1

Outlets
Audio	2

The bank decides the engine. A .syx holds six-operator voices; a .wopn, .tfi or .dmp holds OPN2 instruments for the Nuked-OPN2 core; a .opm holds OPM voices for Nuked-OPM; a .wopl holds OPL3 instruments for Nuked-OPL3. Load one and the right engine plays it: eight voices on the six-operator engine, six channels on the OPN2, eight on the OPM and eighteen on the OPL3. Pitch comes from the patch Tuning, so a microtonal scale plays on chip voices. A patch names its bank rather than carrying it, so share the bank alongside the patch. Cord a PianoRoll, DNA or MidiIn in.

Parameters

Patch	Which voice of the bank plays, by name. Choosing a bank starts again at its first voice.
Bright	How hard the modulators drive their carriers. Centre is the voice as written; up adds harmonics, down closes the tone toward a sine.
Attack	How long every operator takes to open, around what the voice asks for.
Release	How long the voice takes to fade after the key lifts.
Detune	Spread between operators, in cents. Small amounts thicken a voice; large ones beat against themselves.
Vibrato	Depth of the voice's own low-frequency pitch wobble.
Speed	How fast that wobble runs.
Transpose	Shifts the note in semitones. It moves the sounding frequency rather than the note number, so it holds in any tuning.
Fine	Shifts the note in cents, the same way.
Level	Output level.
BendRange	How far the pitch wheel reaches at full travel, in semitones. Two is the common default; zero ignores the wheel.
Algorithm	Which operator drives which, and which reach the output. The six-operator engine offers 32; the chips offer 8.
Feedback	How hard the first operator folds back into itself, 0 to 7.
Op1_Level	Output level of operator 1, and so on for operators 2 to 6. Picking a patch loads its voice into these rows, so what is on screen is what plays.
Op1_Ratio	Frequency ratio of operator 1 against the note, and so on for 2 to 6.
Op1_Detune	Fine offset of operator 1, centred at 7, and so on for 2 to 6.
Op1_Attack	Envelope attack rate of operator 1, and so on for 2 to 6.
Op1_Decay	Envelope decay rate of operator 1, and so on for 2 to 6.
Op1_Sustain	Envelope sustain level of operator 1, and so on for 2 to 6.
Op1_Release	Envelope release rate of operator 1, and so on for 2 to 6.
Op1_On	Takes operator 1 out of the voice or puts it back, keeping its level meanwhile, and so on for 2 to 6. The chips have four operators, so Op5_On and Op6_On are unavailable while a chip bank is loaded.
File	The bank to play from, and with it the engine. Empty is the factory bank; a bank dropped in the banks folder joins the list and shadows a shipped bank of the same name.

Recipe

Chip electric piano

Load the factory chip bank and pick an electric piano patch. Bright 0.6, Detune 6, Release 0.6, Vibrato 0.1, Speed 0.4. Cord a PianoRoll in and a Fern after it with Feedback around 0.4 for the echo; switch Op4_On off and on while it plays to hear what the top operator adds.

Related: Rhizome, Wave, PianoRoll, DNA