Generate unique hip hop beats from scratch — 37 styles, 9 instruments, free, runs in your browser.
Every beat is assembled in real time from hundreds of musical rules — not selected from presets, not generated by AI. Drums, bass, electric piano, synth pad, lead, organ, horns, vibes, and clavinet all play together, following the same chord progressions and reacting to each other. Full song arrangements with intros, verses, choruses, breakdowns, and outros. Export WAV, MIDI, MPC patterns, chord sheets, and PDF beat sheets. No account, no cloud, no subscription.
The beat is the harmonic foundation — you bring the melody. Your rap, your sample, your guitar, your scratch. That's how hip hop has always worked.
| Feature | Details |
|---|---|
| 🎵 37 Styles | Boom bap, G-Funk, Memphis, Dilla, lo-fi, crunk, phonk, Griselda, Nujabes, old school, Detroit, Miami bass, NOLA, Virginia, and more |
| 🎸 9 Instruments | Drums, bass, EP, synth pad, lead, organ, horns, vibes, clavinet — each style gets the right combination |
| 🎧 WAV Export | Full mix with master FX + individual stems for all 9 instruments |
| 🎹 MIDI Export | Full song + individual sections on separate GM channels |
| 📱 MPC Patterns | .mpcpattern files for Akai MPC Live, One, X, Force |
| 📄 Chord Sheets | Piano keyboard diagrams with style-aware voicings |
| 📋 PDF Beat Sheet | Printable color-coded pattern grids |
| 🎛 DAW Guides | Step-by-step setup for Ableton, Logic, FL Studio, Pro Tools, Maschine, Reason, Reaper, Studio One, GarageBand |
| ✏️ Edit Mode | Click cells to add/edit/delete hits, velocity slider, undo |
| 📚 Education | Every beat explains why every kick, snare, and ghost note is where it is |
- Rappers — Hit play and freestyle. Export the WAV for demos. The flow guide tells you where to land your syllables.
- Producers — Export MIDI, swap the sounds, customize in your DAW. The patterns are musically correct — you're not starting from scratch.
- DJs — Full song arrangements with breakdowns for scratching. Export WAV, load on a deck.
- Musicians — Chord sheets, bass MIDI, EP voicings. Play along or study the parts.
- Students — Click any cell to understand its velocity. Read the analysis. Every beat is a free lesson.
312 curated kick patterns. Named player profiles (Premier, Questlove, Dilla, Lil Jon). Per-instrument swing. Modal harmony (Dorian IV for G-Funk, Phrygian bII for Memphis). Bass call-and-response. Tempo-aware generation. Dynamic arrangement arcs. Section-ending fills matched to each era. This is what 40 years of hip hop sounds like when you encode it into code.
The drum engine models over 60 distinct behaviors per style: kick placement libraries curated from real records, ghost note clustering that mimics a drummer's stick control, accent curves that shape dynamics the way a real ride hand does, hat patterns with 3-level velocity dynamics (G-Funk's signature), pocket-delayed snares that land behind the beat (Dilla's trademark), cowbell patterns for Memphis/phonk/crunk, descending 3-tom fills (high → mid → low) at section boundaries, and fill types matched to each era — from a single snare hit (Memphis minimalism) to dense flam rolls (chopped break fills). 8 GM drum kits auto-selected per style: Standard, Room, Power, Electronic, TR-808, Jazz, Brush, Orchestra.
The bass locks to the kick drum and uses correct intervals (5ths, minor 7ths) as passing tones. 10 techniques modeled from session players:
- Monophonic overlap prevention — previous note truncated before new note-on, like a real bass where you can only play one note at a time
- String rake — muted dead-note burst before hard downbeat hits
- Pull-off — descending grace note (5th→root, octave→root)
- Trill — rapid 2-note alternation on the last beat of a bar
- Double-stop — root+5th power chord on section entries
- Upbeat accent — velocity boost on "and" positions for funk displacement
- Rest bar — sitting out an entire bar for phrase-level breathing
- Beat 1 skip — entering on "and" of 1 or beat 2 instead of beat 1
- Rhythmic mutation — shifting ornamental note timing on motif repeats
- Hammer-on grace notes — whole-step approach from below before main notes
Plus: Moog-style glissando slides for G-Funk, sub-octave drops on beat 1 for 808 styles, 2-bar motif development with transposition across chord changes, section-ending fills (walking diatonic runs for jazz, chromatic dissolves for Dilla, sub tail ring for 808), call-and-response with the drum pattern, and tempo-aware density scaling. 6 GM bass sounds auto-selected per style.
Session-player level comping across 12 styles:
- Voice leading — common tones held between chords (Cm7→Fm7: C and Eb stay, only root and 5th move)
- Crushed chords — LH lands 1-3 ticks before RH (bidirectional — 70% LH-first, 30% RH-first)
- Per-note velocity humanization — inner voices softer, root and top note louder (±8 variation)
- Dorian IV correction — G-Funk/Dilla IV chord is dominant 7th (C7, not Cm7) because Dorian has a natural 6th
- Drop-2 voicings — second-from-top note dropped an octave for open Rhodes sound
- Bass avoidance — if bass note matches lowest EP note, uses first inversion instead
- Grace note runs — chromatic approach runs into chorus/lastchorus beat 1
- Velocity swell — soft re-attack at midpoint of sustained chords
- Register thinning — high register uses shell voicings, low register uses root+5th only
- Organ interaction — EP rests when organ is sustaining to avoid harmonic mud
- Damper pedal bleed — notes extend 2% longer than written, simulating pedal sustain
- Duration jitter — ±2 tick variation on note lengths for human feel
- Sus4→3 resolutions, chromatic approach chords, pedal tone drones, ghost re-attacks, kick-locked stabs, drum-density velocity response, section fills, motif-based comping, rhythmic mutation
Acoustic grand piano for jazz/Nujabes/Queens, electric piano for Dilla/G-Funk/lo-fi/bounce.
Dark atmospheric pads for styles where keys would be wrong (Memphis, phonk, Griselda, crunk, dark, hard):
- Phrygian bII emphasis, swell/fade dynamics, kick-locked crunk stabs, drum density response, bar variation with chord extensions, bass register avoidance, strategic rest bars
- Memphis: detuned choir. Phonk: dark string pads. Griselda: cinematic strings. Crunk: aggressive synth stabs.
G-Funk whistle melody — pentatonic scale, Moog-style slides/portamento, 2-bar motifs with call-and-response, upper register (C5-C6). GM Square Lead or Saw Lead.
Sustained drawbar organ for jazz/Nujabes — voice-led whole-note chords, layers with EP (organ sustains while EP comps rhythmically), dynamic section response. GM Drawbar Organ.
Brass section chord hits for boom bap/big/driving/chopbreak/oldschool — kick-locked timing, 3-4 note voicings, staccato duration, velocity variation on downbeats vs off-beats, section-aware density. GM Brass Section.
Bell-like arpeggiated tones for Nujabes/jazzy — broken chord patterns, 2-bar melodic motifs, soft dynamics, pedal sustain shimmer. GM Vibraphone.
Funky percussive 16th-note comping for bounce/G-Funk DJ Quik — syncopated patterns locked to hi-hat groove, muted and accented notes, percussive attack. GM Clavinet.
Modal, not just minor. G-Funk/Dilla/Nujabes use Dorian — the IV chord is major (C7, not Cm7) because the natural 6th degree raises it. Dark/Griselda/Memphis/Phonk use Phrygian bII — the sinister half-step (Db in Cm) that defines their menacing character. Jazz styles include ii-V turnarounds, 6th chords, and chromatic diminished passing chords.
Each instrument swings by a different amount per style — the way real producers program:
- Dilla: hats swing 30% harder than base, kick stays 40% straighter
- G-Funk: bass swings slightly harder than kick for smooth bounce
- Memphis: 808 subs sit near-grid for locked repetition
- Crashes always land on the grid
- Shaker follows hat groove at 90%
- 12 arrangement templates with dynamic energy arcs
- Beat-1 velocity accent across all instruments
- Per-section hat variation (verse vs chorus vs breakdown)
- Filter effect on breakdowns/intros (progressive instrument strip-down)
- Pocket shift in MIDI — chorus pushes slightly ahead, verse lays back
- Beat drops — ALL instruments go silent before re-entries
- 3 intro types (build-in, full beat, minimal count-in) and 2 outro types (fade, stop)
- Section-ending fills matched to each style's era
- Descending 3-tom fills (high → mid → low) at section boundaries
No install needed. Just open hiphopdrummer.com in any browser.
# Or serve locally:
python3 -m http.server 8080npm install # install SpessaSynth + esbuild
npm run build # bundle synth-bridge.mjs → synth.js
npm test # run 18,000+ assertions- 37 styles + 6 regional variants — from old school 808s to modern boom bap revival
- 9 instruments playing together with style-matched sounds (TR-808 for G-Funk, Brush Kit for Nujabes, etc.)
- SpessaSynth audio engine — high-quality GM SoundFont playback
- Per-instrument swing — hats, kick, ghost snares, bass each swing differently per style
- Beat drops — dramatic silences where ALL instruments drop out
- Strict vs Improvise — same part every time, or slight variations like a live band
- Tap tempo — double-click BPM or press T
- Keyboard shortcuts — Space, R, T, E, L, ←/→
- PWA — installable, works offline
- Beat History — 100 slots with favorites
node tests.js # 18,000+ assertions, zero dependenciesCovers all 37 styles × 10 instruments, bass generation, all 7 melodic generators, per-instrument swing, chord progressions, modal harmony, player profiles, MIDI/MPC output, combined multi-instrument MIDI, section transitions, beat drops, strict/improvise mode, and more.
├── index.html App shell and layout
├── styles.css Dark/light theme, responsive
├── patterns.js Style data, kick libraries, swing tables
├── ai.js Generation pipeline, arrangement builder
├── writers.js Bar writers, fills, intro/outro
├── groove.js Accent curves, humanization
├── bass.js Bass generator + MIDI/MPC export
├── ep.js Electric piano (30 features, 12 styles)
├── pad.js Synth pad (10 features, 7 styles)
├── lead.js Synth lead (G-Funk whistle)
├── organ.js Organ (jazz/Nujabes)
├── horns.js Horn stabs (boom bap/big/driving)
├── vibes.js Vibraphone (Nujabes/jazzy)
├── clav.js Clavinet (bounce/G-Funk)
├── analysis.js Educational text generator
├── ui.js Grid, arrangement editor, chord sheet
├── midi-export.js MIDI/ZIP export, combined 9-instrument MIDI
├── daw-help.js DAW setup guides (9 DAWs + MPC)
├── pdf-export.js PDF beat sheet + chord sheet
├── beat-history.js History storage and dialog
├── app.js Main controller, dialogs, playback
├── synth-bridge.mjs SpessaSynth integration (ES module)
├── synth.js Bundled synth engine
├── tests.js 18,000+ automated assertions
├── sw.js Service worker (offline PWA)
├── manifest.json PWA manifest
├── robots.txt Search engine directives
├── sitemap.xml Search engine sitemap
└── GeneralUserGS.sf3 GM SoundFont (10MB)
MIT — see LICENSE.
Beats you generate are yours. Commercial releases, demos, freestyles, DJ sets, samples, remixes — no attribution required, no royalties, no restrictions.
Artist, producer, and track references throughout Hip Hop Drummer are for educational purposes only. This project is not affiliated with or endorsed by any artist, producer, label, or company mentioned.
All product names, logos, and brands — including Roland, TR-808, Akai, MPC, E-mu, SP-1200, Moog, Minimoog, Korg, Triton, Juno, Prophet, Sequential, Oberheim, Fender Rhodes, Wurlitzer, Teenage Engineering, Ensoniq, Boss, Casio, Yamaha, Steinway, and others — are trademarks or registered trademarks of their respective owners. Use of these names is for descriptive and educational purposes only and does not imply any affiliation or endorsement.
Built by Keith Adler · hiphopdrummer.com