MDSQ

MDSQ — FM Sequencer ROM for Genesis / Mega Drive

MDSQ is a real-hardware step sequencer directly driving the YM2612 FM chip and the SN76489 PSG.  

Featuring:

Full 4-operator synthesis engine using 128 Yamaha TX81Z  rom voices written verbatim to the YM2612, across 10 editable channels — 6 FM voices, 3 PSG tones and 1 noise channel — 128-step pattern shown 32 steps per page over 4 pages.
Real-time editing of all parameters, notes, effects and channel copy during playback.

BRIGHT, ATK and REL — let you nudge a patch from neutral without touching individual operators. Each track has its own loop length for polymeter, and every step carries a stack of automation: NOTE (quantised to a selectable scale — chromatic, major, minor, dorian, mixolydian, harmonic minor, pentatonic or blues), INST preset, and per-step VOL,  gate, pan, detune, decay, probability, swing, tie/legato, retrigger, slide, vibrato, arpeggio, plus two software effects — ECHO (a decaying delay/slapback that rides the source voice) and  ZAP  (an up or down pitch sweep for lasers, pews and kick drops). Editing happens on a single tiled grid with a live playhead: notes are drawn by pitch (and auditioned as you scroll rows), timbres and values are painted with contour and rhythm fill gestures, and pages can be copied and propagated to build a full arrangement. A dedicated noise editor dials four noise voices by pitch and decay in an XY view and sequences them separately. Performance features include live speed/direction on a reverse-to-forward continuum, swing, per-channel mute and solo, page looping, four pattern slots chained into a song, one-level undo/redo, and a 10-style / 8-palette audio visualiser with oscilloscope and starfield modes. The whole UI is designed around a plain 3-button pad — everything is reachable with A, B, C, Start and the D-pad.

PLEASE READ THE README for controls.

Demo is limited to 3 channels and one page.

Design and testing by a human, code by Claude.