BOOM BAP - A Game Boy MIDI sync loop sampler, 221 Loops - Downloadable ROM (v1.0)

BOOM BAP! the sequel to DRUM & BASS II...

221 sample loops. MIDI sync.

BOOM BAP is a Game Boy ROM packed with 221 loops. Sync it to your DAW via Arduinoboy, or play standalone as a master clock. Built for live performance and studio use.

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

Sounds best on a Gameboy DMG, sounds acceptable on Gameboy Color, Will sound very noisy on GBA!

What you get:

• Game Boy ROM file (.gb), works on real hardware (DMG, GBC).
• 221 selectable loops with on-screen browser
• MIDI clock slave sync (Arduinoboy LSDJ Slave mode)
• Master clock mode (sends MIDI to other gear)
• 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
• DMG backwards compatible
• ROM is 4MiB
  
  

How to use it:

Flash to a cart (EverDrive, insideGadgets, etc.)

Connect an Arduinoboy or LSDJ for MIDI sync.

ALL CONTROLS

Selection Screen

• UP; Move cursor up one sample
• DOWN; Move cursor down one sample
• UP (hold); Fast scroll up (starts after 0.5s, scrolls at 15 items/sec)
• DOWN (hold); Fast scroll down
• RIGHT (hold); Preview selected sample (plays while held, stops on release)
• A; Enter MASTER mode (plays immediately, sends MIDI clock out via serial port)
• B; Enter SLAVE mode (waits for external MIDI clock sync via Arduinoboy)

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.
• 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
  
• SELECT + UP; Increase timer modulo (slower tempo)
• SELECT + DOWN; Decrease timer modulo (faster tempo)
• START; Stop playback (silence)
• START (again while stopped); Return to sample selection screen

Requirements:

• Boy DMG or Game Boy Color, does not work well on GBA sound chips!
  
• For DMG CPU Revisions CPU - 04 or later sound best!
• DMG sounds the best in general!
• Arduinoboy for MIDI sync (optional; works standalone in master mode
  

Known bugs:

• No stutter glitch in slave mode (PLL conflict) (Using detune instead)
• Low BPM sync issues for 8-beat samples
• Slight off-phase on first beat in slave mode unless tempo has been primed.
• mGB Arduinoboy mode not recommended due to clock being laggy there (fix for another day)
• Waveform at 15fps (intentional tradeoff)
• Sounds like garbage on gBA.
  
  All 221 drum loops are public-domain (CC0) samples sourced from Freesound.org. Huge thanks to the 60 contributors who released their work CC0: DirtyArchives, firnwald, newshooze, hello_flowers, Bronxio, Schulze, colano100dio, msx2plus, Snapper4298, CVLTIV8R, Dolfeus, NovaSoundTechnology, PareeKatti, schafferdavid, vekoN, Zajo, crash_358, DigitalUnderglow, oceansonmars, waveplaySFX, bigjoedrummer, Blackie666, deleted_user_2906614, h3rb4, hardwareshaba, KatHakaku, Liquid_Tribal, mika55, nickm, RutgerMuller, xanthorp, adh.dreaming, Cat-Fox_Alex, cheeseymofodude, Crabflag, DABROmusic, Dwy, ErrorCell, fawkes027, Fejluh, holizna, Insidebeat, Kodack, le NEKO, lennartgreen, melisandepope, Patitodilluvio_, pbdlugoss, reklamacja, shart69, SiliconMusic, staticpony1, stenchwank, suspiciononline, The-Sacha-Rush, TheFlakesMaster, Theo_Lusvordes, thunderstorm10, Uberproduktion, unfa.
  
  
• Developed by HobbyChop 2026