01

SP-404MKII synth patcher

Tracelistener's Sound Generator v9.9.3 mod: four live voices, 17 added waves, volume/filter-envelope presets, 34 scales and an arpeggiator. Your firmware stays in your browser; nothing is uploaded.

Synth build
v9.9.3
Live voices
4
Added waves
17
ENV presets
9 + OFF
1

Compatible with stock firmware . Select Sound Generator to include the mod; unchecked generates the base build without these synth additions.

v9.9.3 fixes the reproduced BANK-tempo mismatch and passes 71 emulator checks; hardware confirmation of this build is pending. CPU headroom remains unmeasured. Our arpeggiator notes and test instructions · v9.6 scales and fixes · wave list · source code · Wave Lab preview

Envelope preset guide (ENV)

In Sound Generator, choose ENV, then play a new note to hear the selected preset. Each voice takes its envelope when the note starts. Presets work on stock and added waves, four-voice playback and held-chord REC.

  • OFF: stock behavior, no added envelope.
  • Pluck / Perc: fast attack and decay to silence; Perc has the longer decay.
  • Keys: fast attack, quieter held level and a release tail.
  • Pad / Swell: soft fade-in and long release; Swell is slower.
  • Bass / Acid: volume plus a closing resonant low-pass filter; Acid has stronger resonance/drive and a shorter release.
  • Sweep / FPad: volume plus slow filter movement; Sweep opens slowly, FPad has a softer volume attack and long release.

ENV selects fixed presets, not separate ADSR knobs. Release tails continue after note-off; all-stop still cuts them with the stock fade. These are custom envelopes/filter, not a ZEN-Core port.

34 scales and MIDI IN (v9.6)

Set SCALE to anything other than Chrom and the 16 pads play only that scale's notes, one scale step per pad, from the bottom row (lowest) to the top row (highest). Pad 9 plays the first scale note at or above its usual note, so one bank spans two octaves and a step with a 7-note scale, or three octaves with a pentatonic one. Chrom and the other screens work as before.

34 choices now include Lydian, Mixolydian, Locrian, blues, bebop, harmonic/melodic minor, whole tone, diminished, Gypsy/Romanian minor, Spanish, Bhairav, Marva, Purvi, Todi, Arabic, Egyptian, Chinese, Pelog, Hirajoshi, Miyakobushi and Ryukyu. The original choices are retained. Added choices act as Chrom outside Sound Generator; extreme OCT settings can put some pads beyond the playable pitch range.

Fixed: releasing pads after large OCT/ROOT/SCALE changes no longer causes the reproduced stuck-note bug. FREQ transposes fitting chords within shared bounds; a MIDI chord wider than 84 semitones stays unchanged when FREQ is adjusted, preserving its intervals.

MIDI IN plays all four voices, with the same voice stealing as the pads; a held MIDI note lights the pad with the same pitch. When all four voices are busy, a new note takes one after a 2.8 ms fade-out, so swapping notes in a chord does not click. Recordings with an ENV preset fade out at the end, and pressing REC while holding notes fades them instead of cutting them.

Arpeggiator guide (v9.9.3)

Five items follow TUNE in the Sound Generator VALUE menu; use them like the others (move to the item, enter edit, turn).

  • ARP: OFF, UP, DOWN, UP&DN, RAND, ORDER (the order you pressed the keys), CHORD (all held notes every step).
  • RATE: 1/4, 1/4T, 1/8, 1/8T, 1/16 (default), 1/16T, 1/32 of a beat.
  • A.OCT: -3..+3, also plays the held notes that many octaves below/above.
  • HOLD: latch; the arp keeps going after you let go, and the next key after letting go of everything starts a new chord.
  • BPM: read-only, the tempo the arp plays at.

With ARP on, pads and MIDI IN feed the arp instead of playing directly. Each step is released half a step later, so the ENV preset shapes every step and release tails overlap. The arp follows the tempo BPM-synced samples in the current bank follow: the PROJECT BPM, the bank's own BPM when the tempo is set to BANK, the MIDI clock when synced, or a playing pattern's tempo. It runs free from the first key, not locked to the pattern's beat grid. Turning ARP on stops notes played directly; leaving the Sound Generator page stops the arp. Settings reset at power-on.

2

Prepare your test update

  1. Back up your samples, projects and settings. Keep the original Roland 5.52 update and your working build.
  2. Load the unmodified stock 5.52 SP404MKII_APP1.bin above. Select Sound Generator for v9.9.3: four voices, all 17 new waves, envelopes/filter presets, 34 scales and the arpeggiator.
  3. Download the result as SP404MKII_APP1.bin. Use it with the unchanged official 5.52 SP404MKII_APP0.bin and your established SD-card update procedure.
  4. Return to the known-good update for hangs, stuck notes or audio breakup.