BLAST — fourteen OPL2-style FM models for the Model:Cycles

BLAST is one added machine for the Elektron Model:Cycles, OS 1.13: fourteen melodic FM models built on a two-operator FM engine in the manner of the Yamaha OPL2. A '90s PC SoundBlaster engine, with a stepped modulator ratio on SWEEP.

This repository is the machine's source package, published so that other projects can port it. It is not a firmware and contains none.

Hear it: BLAST on YouTube
Flasher: 100demons.github.io/cycles-engines/flasher — tick BLAST and bring your own official model-cycles_OS1.13.syx.

The models

SHAPE picks the model. The names are shown on the machine's screen.

SHAPE	Model	What it is
0	SIN	Sine: clean two-operator FM, modulator depth on COLOR
1	HLF	Half-sine: hollow, reedy carrier
2	ABS	Absolute sine: folded wave, octave-rich and bright
3	PLS	Pulse: nasal, square-edged carrier
4	BAS	Bass: short FM slap over a round body
5	PIA	Piano: bright bark settling into a round tone
6	MAR	Marimba: fundamental plus tuned overtone, mallet click
7	GLK	Glockenspiel: bright strike with a quiet high partial
8	BRS	Brass: slow swell into a sustained brass
9	ACC	Accordion: two detuned half-sine reeds
10	STR	Strings: feedback saw modulator with a bowed attack
11	STL	Steel drum: hollow ring with a semitone blip
12	TMP	Timpani: felt thud and a long low membrane
13	ZAP	Laser: four-octave pitch fall

The knobs

Knob	What it does
PITCH / FINE	the note, as on every machine
COLOR	Index: the FM modulation index / modulator level, the mallet hardness or the feedback
SHAPE	the model (the table above)
SWEEP	the fixed modulator:carrier ratio, 1:2 to 15X, stepped; FUNC leaves the steps
CONTOUR	Env: how the sound moves (brightness decay, swell, feedback, detune, mallet click)
DECAY	the decay, or release when GATE holds the note
GATE	BRS, ACC and STR sustain; PIA, MAR, GLK and STL delay the damper so long notes ring
PUNCH	vibrato on SIN, HLF, ABS, PLS, MAR, BRS and STR; tremolo on BAS, PIA, GLK and STL; ACC gets both; TMP and ZAP ignore it

Status

Package	cycles-mod/0.1, the model27/cycles-engines package format
Slot in the flasher	9 (the OS numbers it machine 8)
Committed object	blast.o; core/build_engine.py blast --check passes
Emulated	the source tree's bridge proof (all 14 models, GATE, silence, cost, memory, stack) and OS proof (boot, descriptors, names, ratios, voice loop) passed
Tested on a real Model:Cycles	not yet
Weight	about 60 to 84 % of a stock TONE voice per block; a silent voice costs almost nothing
License	MIT

BLAST makes its own envelopes; the stock amp chain is not called. A silent voice is not computed. The OS still sets the volume and applies velocity after the voice.

Package layout

tools/machines/blast/
  manifest.json    the package: build recipe, symbols, claims, tests, compatibility
  card.json        the flasher card: label, description, status, video
  blast.c          the voice-loop bridge
  blast_dsp.h      the FM engine (two operators, OPL2-style log-sine and power tables)
  blast_tables.h   the generated tables
  blast_icons.h    the splash artwork (the package still shows TONE's stock MACHINES picture)
  blast.o          the committed relocatable object
  LICENSE          MIT

There is no firmware here: the package is applied to the user's own official OS file by a host such as cycles-engines.

Build and check the object

The package builds with the cycles-engines toolchain. Copy tools/machines/blast/ into a cycles-engines checkout as engines/blast/, then:

export M68K_CROSS=/path/to/bin/m68k-elf-        # or have m68k-elf-gcc on PATH
python3 core/build_engine.py blast --check

--check rebuilds blast.o from blast.c and the manifest's recipe and compares it with the committed object. The composer and the flasher never need the toolchain: they place the committed object.

Install

Easiest: tick BLAST in the flasher and bring your own official OS 1.13 file. Or download blast-3.0.zip from this repository's Releases and add the folder to your own build.

Credits

• Engine, tables and design: 100demons, MIT.
• The OPL2 is named as the synthesis model; no Yamaha code, ROM dump or sample is included. See THIRD-PARTY-NOTICES.md.

Changelog

See CHANGELOG.md.