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Synth & Bass I & II - A Game Boy MIDI sync synth loop sampler, 254 synth loops - Download ROM -V1.3

$16.00
Synth & Bass I & II - A Game Boy MIDI sync synth loop sampler, 254 synth loops - Download ROM -V1.3
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SYNTH & BASS I + II - Game Boy Synth Loop Player ROMs (two roms)

254 synth loops on two roms. MIDI sync. The companion to DRUM & BASS III.

SYNTH & BASS is two Game Boy ROMs, 127 synth loops each: subs and reeses, acid lines, neuro wobbles, FM growls, pulse and supersaw leads, chip arps, plucks, pads, strings, choirs, vox chops, jungle stabs, hoovers, electric piano, organ, risers and bells. Volume II adds halftime subs, growls, donks, foghorns, square arps, supersaw stabs, pluck chords, bell pads, DX-style keys and vocoder vox: 127 more, all new material. Every loop on both carts is two bars in A minor at 174 BPM, so everything works with everything: the two volumes with each other, and both with DRUM & BASS III. Link two Game Boys over MIDI clock and one plays the breaks while the other plays the bass and the tops; link three and you have a synth each.

It is the same engine as DRUM & BASS III, so everything you learned there carries over: queue loops live, record your chops into patterns, chain patterns into songs, follow your DAW or be the clock.

Built with assembly for cycle exact audio streaming and midi timing precision.

Sounds best on a Gameboy DMG, good on Gameboy Color, acceptable on GBA.

What you get:

  • Two Game Boy ROM files (.gb), SYNTH & BASS I and SYNTH & BASS II, each 4 MiB: they fit the common 4 MB carts. Work on real hardware (DMG, GBC, GBA).
  • 254 synth loops with on-screen browser, 127 per cart, every loop two bars, every loop in A minor
  • Rendered for these carts: synthesised offline, level matched and anti-aliased for the Game Boy's wave channel, streamed at ~24 kHz
  • Native tempo 174 BPM: in tune at drum & bass tempo, and it transposes with the BPM like a sampler
  • BPM control (61–250), shown on every screen
  • Live sample switching: queue the next loop, it takes over at the loop start without dropping the clock
  • Live sample list: open the browser mid-performance while the loop keeps running
  • Record one pass of your chops and glitches into a pattern (SELECT + A), clear it again with SELECT + B
  • 255 pattern slots and 64 songs per cart, saved on the cart
  • PICK setting: while a song plays, SELECT + LEFT/RIGHT can walk just that song's parts and jump between them
  • Momentary mute and a latched silence for drops
  • MIDI clock slave sync (Arduinoboy LSDJ Slave mode)
  • Master clock mode (sends MIDI to other gear, evenly spaced 24 PPQN)
  • Connect it to LSDJ directly as a slave (LSDJ in LSDJ mode)
  • Live glitch controls: envelope stutter, pitch bend, loop freeze
  • Game Boy Color enhanced with colorful waveform display and a loop position bar; the waveform reacts to what is in force
  • DMG backwards compatible

The loops:

SYNTH & BASS I (127)

  • Bass (30): sine subs, reeses, neuro wobbles, 303 acid lines with accents and slides, FM growls
  • Leads (20): PWM pulse hooks, supersaw legato lines, chip pulse arps, FM leads
  • Arps (18): plucked 16th and 8th arpeggios, FM bell arps, pluck melodies
  • Pads (18): supersaw pads, PWM pads, strings, choirs, drones
  • Vox (10): formant voices on melodies, chopped vowels
  • Stabs (16): jungle chord stabs, hoovers, brass hits
  • Keys (8): electric piano and drawbar organ chords
  • FX (7): two-bar risers, gated noise, bells

SYNTH & BASS II (127)

  • Bass (32): subs, halftime subs with slides, reeses, neuro wobbles, FM growls with a wobbling index, 303 acid lines, FM bass, donk offbeat plucks
  • Leads (20): PWM pulse hooks, supersaw legato lines, chip leads, FM leads, foghorns
  • Arps (18): plucked arpeggios, square arpeggios through a filter envelope, FM bell arps, pluck melodies
  • Pads (16): supersaw pads, PWM pads, strings, choirs, drones, bell pads
  • Vox (10): formant vox on melodies, vocoder-style vox with a vowel change every 16th
  • Stabs (16): jungle chord stabs, supersaw chord stabs, hoovers, brass hits, pluck chords
  • Keys (8): electric piano, drawbar organ, DX-style FM keys
  • FX (7): two-bar risers, gated noise, bells

The two carts share no loops. Patterns and songs are saved per cart, in its own save RAM.

How to use it:

  • Flash each ROM to a cart that takes 4 MiB ROMs or larger (EverDrive, insideGadgets carts, etc.)
  • Connect an Arduinoboy or LSDJ for MIDI sync.
  • On the selection screen press RIGHT until the SET tab: hold A and press LEFT/RIGHT to set your BPM, DOWN to the CLOCK row for CLK.OUT (the Game Boy sends MIDI clock) or CLK.IN (it follows the clock from an Arduinoboy or LSDJ). Both are remembered. LEFT back to LOOPS, pick a loop, press A.
  • Two Game Boys: set DRUM & BASS III to CLK.OUT and SYNTH & BASS to CLK.IN (or the other way round), link them, start the CLK.IN unit first, then press A on the CLK.OUT unit. Both are in tune at 174.

ALL CONTROLS

The d-pad moves, A does, B goes back, A + d-pad edits a value, and holding a button for one second does the big things (a bar fills up while you hold). The screen never blanks while you browse.

Selection Screen

  • UP / DOWN; Move the cursor (hold to fast scroll). The lists wrap: UP from the top row jumps to the bottom, DOWN from the bottom to the top.
  • LEFT / RIGHT; Switch tab: LOOPS, PATTERNS, SONGS, SET
  • B (hold); Preview the highlighted loop at the set BPM (stops on release)
  • A; Play what is highlighted, in the set clock mode (CLK.OUT: at once, sending clock; CLK.IN: when clock arrives). A loop always starts PLAIN: pick a pattern on the PATTERNS tab or record one to put a chop on it.
  • START; Play the selected song from the top, in the set clock mode. Works from any tab, so from power-on it is one press.
  • START (hold 1 s); Clear the highlighted pattern slot / song / part
  • SET tab; BPM, CLOCK and PICK rows. Hold A and press LEFT/RIGHT to change the highlighted one (BPM repeats while held).
  • BPM 61-250. CLK.OUT = the Game Boy sends MIDI clock; CLK.IN = it follows the clock from an Arduinoboy or LSDJ. PICK = what SELECT + LEFT/RIGHT walks through on the play screen while a song plays: ALL LOOPS (any loop, as always) or SONG PART (only the parts of the song that is playing). All three are remembered on the cart. The clock setting changes on the selection screen only.

Play Mode

  • A (hold); Envelope glitch effect. Creates a stuttering volume modulation synced to the sample position. Different timing = different sound each time.
  • A + LEFT; While holding A, increase envelope intensity (faster modulation)
  • A + RIGHT; While holding A, decrease envelope intensity (slower modulation)
  • A (release); Envelope turns off, intensity resets to default for next press
  • B (hold); Loop stutter glitch. Restricts the sample pointer range creating short repeating fragments. The shorter the range, the faster the stutter. (CLK.IN: pitch effects instead, B + d-pad for variants)
  • B + UP; While holding B, tighten the stutter (shorter loop = faster repeat)
  • B + DOWN; While holding B, loosen the stutter (longer loop = slower repeat)
  • B (release); Normal full-length loop resumes
  • D-Pad; Sample section offset modifier (chops the phrase on the 16th-note grid)
  • SELECT (tap); Open the live menu while the loop keeps playing (while stopped: the selection screen)
  • The bar under the waveform fills as the loop plays: two 16th-note steps per block, empty again at every loop start.
  • START; Stop playback (silence). START again plays from the top: the loop, or the song from its current part.
  • SELECT (tap while stopped); Back to the selection screen
  • SELECT Layer (hold SELECT; the d-pad and A/B effects pause and a key legend appears)
  • SELECT + UP/DOWN; BPM up/down by 1 (hold to repeat). CLK.OUT only; with CLK.IN the readout shows the incoming tempo.
  • SELECT + LEFT/RIGHT; Pick the NEXT sample. Let go of SELECT to queue it; it takes over at the next loop start, PLAIN (a pattern that was on is dropped).
  • With PICK set to SONG PART and a song playing, this walks the song's parts instead: NEXT shows P02 and the part's pattern (or SILENCE), and letting go jumps the song to that part at the next loop start. The song keeps going from there.
  • SELECT + A; Record: WAIT until the loop restarts, then REC for one pass of two bars. Everything you play with the d-pad, A and B is written into the pattern, and plays back on its own from the next pass. Steps you leave alone keep what they had, so you can layer passes. Keep it: SELECT, RIGHT to PATTERNS, A on an empty slot.
  • SELECT + B; Clear: the loop goes on PLAIN (a WAIT or REC is dropped too). Save first if you want to keep the pattern.
  • SELECT, then START (hold both); Momentary mute. Sound returns when either button is released.

Live Menu (SELECT tap while playing; the loop keeps running)

  • The tab bar starts with PLAY: LEFT from LOOPS, B, or another SELECT tap brings you back to the play screen.
  • LEFT / RIGHT; Switch tab: PLAY, LOOPS, PATTERNS, SONGS, SET
  • UP / DOWN; Browse (hold to fast scroll, wraps at both ends). * marks what is playing, + what is queued.
  • A; Queue the highlighted loop (PLAIN), pattern or song for the next loop start and return to the play screen
  • B; Back without changes (in PARTS: back to SONGS)
  • SET tab; A + LEFT/RIGHT on the BPM row changes the tempo at once (CLK.OUT).
  • B (hold 1 s); Record one pass (the same as SELECT + A on the play screen)
  • A + B together; Silence. Back on the play screen the loop keeps running muted, clock and sync intact, and the next press of any button brings it back.
  • START; Stop playback (START again on the play screen starts it over)

Patterns

A pattern is a loop plus what you did to it over its two bars: a 32-step chop (which 16th-note slice plays on each step), an automation lane (stutter, envelope glitch, pitch and mute per step) and the tempo. 255 slots per cart, saved to the cart (battery save). Slot 000 is PLAIN: the loop as it is. On a synth loop the chop is a re-sequencer: a pad becomes a gated rhythm, an arp becomes a new arp.

PATTERNS tab

  • A on an empty slot; Save what is playing into it (auto-named after the loop, e.g. ACID-003). The header says EMPTY. A SAVES HERE while the cursor is on one.
  • A on a saved slot; Load it (selection screen: play it; live menu: it takes over at the next loop start)
  • A (hold 1 s); Save over the highlighted slot, used or not
  • START (hold 1 s); Clear the highlighted slot
  • The play screen shows PATTERN 003 ACID-003; a * instead of the space means it changed since it was loaded.

Songs

A song is a list of patterns (or SILENCE parts) with a repeat count each, played in order and looped. The Game Boy moves to the next entry on its own at the loop start, so entries chain seamlessly with CLK.OUT and CLK.IN. 64 songs of up to 32 parts per cart. Every edit is written to the cart as you make it; there is nothing to save.

SONGS tab

  • UP / DOWN; Pick a song. The highlighted song is the selected one. * marks the playing song, + the queued one.
  • A; Play it from the top (selection screen: in the set clock mode; live menu: queued at the next loop start)
  • A (hold 1 s); Open the song's parts (the header reminds you: HOLD A FOR THE PARTS)
  • START; Play the selected song from the top (selection screen; from power-on that is one press: the song and the clock setting are remembered)
  • START (hold 1 s); Clear the song
  • PARTS (hold A on a song; B goes back to SONGS)
  • UP / DOWN; Browse parts. The last row is END and names the song.
  • A on END; Add a part (the first saved pattern, x1)
  • A on a part; Play the song from this part (selection screen: in the set clock mode; live menu: queued at the next loop start)
  • A + LEFT/RIGHT; Change the part's pattern (steps through saved slots; past the last one, or before the first, is SILENCE: a rest of that many loops, clock still running)
  • A + UP/DOWN; Repeats, 1 to 16
  • START (hold 1 s); Delete the part
  • Queueing a loop or a pattern by hand ends the song. The play screen shows S03 02/05 and the part's pattern name; during a rest the NOW line reads SILENCE, and NEXT reads SILENCE when a rest comes next.

Requirements:

  • Game Boy DMG, Game Boy Color or GBA (DMG sounds best)
  • One flash cart per volume with 4 MiB ROM support and battery-backed save RAM for patterns (each ROM declares 32 KiB; without save RAM patterns and songs last until power off)
  • For DMG CPU Revisions CPU - 04 or later sound best!
  • Arduinoboy for MIDI sync (optional; works standalone with CLK.OUT)
  • Tempo range: 61–250 BPM for every loop (same range as DRUM & BASS III and BOOM BAP, so the carts can be linked)

Good to know:

  • Pitch follows tempo, like a sampler: the loops are in tune at 174 BPM and move a semitone per ~10 BPM either way. Run linked carts at the same BPM and they stay in tune with each other.
  • With CLK.IN, set the BPM before pressing A: the clock follower pre-locks to it and lands on the first beat faster
  • Fast tempo sweeps can push a CLK.IN Game Boy off phase; step the tempo instead, or press START twice on the CLK.OUT unit (stop, start) to restart both together
  • Two linked Game Boys: start the CLK.IN unit first, then press A on the CLK.OUT unit, so both start on the same bar
  • No stutter glitch with CLK.IN (PLL conflict) (Using detune instead)

All 254 loops were synthesised for these carts by HobbyChop. No samples from other libraries.

Developed by HobbyChop 2026