A full band studio
that runs in your browser.
MusicFactoryEngine turns a single web page into a playable studio: real sampled instruments, a step sequencer, a mixer with a master effects rack, whole-song generation in the style of famous artists, sample recording, phase-vocoder pitch & stretch, and one-click WAV / MP3 export. This guide walks through the whole flow — from pressing Start Audio to exporting a finished track.
Real instruments
Drums, guitars, piano, strings, brass, woodwinds, organ and synth keys — real audio recordings bundled with the app, with synth fallbacks behind them.
Generate songs
Randomize a full arrangement in the style of 130+ featured artists, each with its own original signature melody, groove and progression.
Mix & shape
A per-track mixer plus a master effects rack, sound types, amp tones and guitar distortion sculpt the sound.
Phase vocoder
Shift pitch and stretch time independently on samples and on the final export, powered by PhaseVocoder.js.
Works completely offline
Every library, font, icon and instrument recording ships inside the folder — nothing is fetched from the internet, ever. Open index.html straight from disk and the whole studio runs with the network switched off, real sampled instruments and all.
Serve the folder over http://localhost (or any https address) and Chrome will offer to install it: an Install App button appears in the top toolbar, a service worker caches the studio, and it then opens in its own window straight from your desktop with no connection at all.
From silence to a finished track
Follow these steps in order — the studio is designed to be used from top to bottom.
Start the audio engine
Click Start Audio in the top toolbar. Browsers only allow sound after a click, so this unlocks the engine and fades the master in cleanly.
Pick an instrument
Choose a card in Band Instruments. Play it with the on-screen piano, the keyboard keys A–K, or the chord pads.
Generate or build a song
Press Randomize Song to create a full arrangement in an artist's style, or build your own by adding parts to the Loop Sequencer.
Arrange on the timeline
Every track is a block you can trim, expand and move, just like clips in a modern DAW.
Shape the sound
Balance levels in the Mixer, dial in the Effects Rack, and adjust global Pitch and Stretch in the toolbar.
Record, export & save
Record a performance, export a WAV or MP3, and save the whole project to a file so you can reload it later.
The panels, one by one
The studio is organised into collapsible panels. Here is what each one does.
Top toolbar
Transport (Play, Stop, Record, Click, Clear), Save / Load Project, and global sliders: Tempo, Master, Octave, plus phase-vocoder Pitch & Stretch.
Band Instruments
Real sampled instruments plus a Sound Type selector, per-instrument amp tone, and a distortion selector for electric guitar.
Song Presets
One-tap patterns that load a ready-made groove so you can start playing straight away.
Selected & Piano
The performance area: playable pads, a fully polyphonic piano keyboard, Record Sample, Record Mic, Generate Music, Export Sample, and a multi-instrument Sample Sequence (8 / 16 / 32 steps) under Amp Tone.
Effects Rack
The master effects, sitting under the piano: Reverb, Delay, Feedback, Chorus, Drive, Filter, Crush and Swing.
Mixer & Sequencer
A full-width mixer with a fader, mute and solo per track, and a bar-based Loop Sequencer for the whole song.
The piano is a standard polyphonic keyboard: hold several keys together to sound a chord, and each note stops the moment you release its key. Press Stop Playing to release everything at once.
How the audio actually travels
Every instrument feeds its own mixer channel, passes through optional tone inserts, and joins the shared master effects chain before it reaches your speakers. Drag to pan, scroll or use the buttons to zoom.
Generate, in the style of the greats
MusicFactoryEngine can build whole songs and short samples for you. Nothing is copied from real recordings — each of the 130+ artists is an original blend of tempo, groove and chord progression, titled after one of their real top-5 songs. Every style plays its own tune: pick Shakira and you get Shakira's signature four-bar hook, pick Metallica and you get Metallica's — stable for that artist, different for every other one. On “Surprise Me” the studio samples one of five original songs instead, one per category — Neon Avenue (Pop), Boom Bap Boulevard (Hip-Hop), Blue Room Shuffle (Jazz & Blues), Circuit Sunrise (Electronic) and Dust & Pine (Country & Folk). Every hook develops across four bars — statement, answer, lift and cadence — so nothing loops a single bar at you.
Randomize Song
Pick an artist or genre, or leave it on “Surprise Me”. The studio lays down drums, bass, chords, an optional pad and a fresh lead across the timeline, and titles it after one of that artist's real top-5 songs.
The lead plays the chosen style's own signature hook — the status line names it — while the tone, the fill and a small transpose change every time, so it is the same tune performed fresh rather than a copy.
Generate Music sample
Generate Music renders a clip for the selected instrument in the Style you choose beside Amp Tone. Pick an artist and it plays that artist's signature melody and is named after one of their songs; leave it on “Surprise Me” and it samples one of the five songs instead, named like “Circuit Sunrise · Electronic”.
The system chooses the Sound Type for you and layers it with your amp tone and guitar distortion, so every clip sounds a little different.
Swap an instrument's real timbre for a synth voice — electronic, techno, synth pad, retro, FM, supersaw and more.
Drive plus a three-band EQ, with 34 voicings from Classic Rock and Jazz to Metal, Djent and Lo-Fi.
The electric guitar adds distortion of sizes, angles, distances and directions — drive, bit-crush, space and stereo movement.
Arrange like a modern DAW
The Loop Sequencer is a bar-based timeline. Every part drops as a block sized to its own sound length — a phrase, a groove or a sample clip — so you can shape the arrangement the way you would in Soundtrap or GarageBand.
Trim
Drag either edge of a block inward to shorten which part of the track plays.
Expand
Drag an edge outward — past the end and the song grows to make room automatically.
Move
Grab the block's header to slide the whole part — its notes travel with it.
Copy & Paste
Duplicate a block with its copy button, or select it and press Ctrl+C then Ctrl+V.
Add or remove bars, set a per-clip tempo, and edit any step cell by clicking it. While a song is still auto-generated, the top Play button spins up a fresh random title each time — as soon as you edit a block, it becomes yours and Play just plays it.
Capture and reshape sound
Record the studio's own output or your microphone into a sample slot, then bend it with the global phase vocoder.
Record & upload samples
Rec Sample captures whatever the studio is playing; Record Mic captures your microphone; and you can upload a WAV or MP3. Each lands in its own slot with a fader and channel — and an uploaded track drops straight onto the timeline at bar 1, so every upload plays in sync with the song.
Pitch & Stretch
The toolbar's Pitch and Stretch sliders drive PhaseVocoder.js: Pitch shifts by semitones while keeping length, and Stretch changes length while keeping pitch — applied to your samples and to the final export.
Sample-sequence drum machine
Under Amp Tone, tap Add to layer instruments as rows in one grid, pick a length of 8, 16 or 32 steps, then program each row. Choose a tone first — click a drum pad (Kick, Snare, Hi-Hat…) or play a chord on any instrument (C major, then G major…) — and each Add inserts that exact tone as its own row. So you can stack two piano chords, three drum pieces and a bassline together. Press Play to loop it all, and Clear to reset. Every instrument on a step is locked to the same beat on the audio clock, so the groove stays perfectly in sync.
Sample & loop stay out of each other's way
Sample playback and the Loop Sequencer are mutually exclusive: starting a sample — Play Sample, Generate Music or the step-sequencer — stops the loop, and starting the loop stops the sample.
Turntable Scratching
Two real decks sit just above Amp Tone. Pick what each one spins from its Sound menu — any instrument, a synth or a recorded sample — or leave it on “Selected instrument” so it follows the rack. Each deck has its own Import button for putting an MP3, WebM, WAV or MIDI file on that deck (a MIDI file is performed with the studio's own voices, since browsers can't play MIDI directly), while Import to Both at the top loads two files at once — one per deck. Generate Music cuts a fresh clip in the chosen Style onto each deck instead, and Clear All Music empties the decks and stops everything that is playing — the platters, the sample and the loop — so whatever you press next starts cleanly.
Each deck runs like a real turntable: Play spins the platter at 33⅓ and the music plays continuously, so you are always cutting into something musical. Grab the record and it follows your hand exactly — drag back and it plays in reverse, hold it still and it goes silent, let go and the motor pulls it back up to speed with an audible bend. Cue drops the needle back at the start and Reverse spins the whole record backwards. A speed-following filter keeps slow drags dark and thick, just like a needle in a groove.
Every deck carries a full channel strip: Volume, a ±16% Pitch fader, a sweepable Filter (low-pass to the left, high-pass to the right) and Low / Mid / High EQ, plus a track slider under the platter that follows the needle and lets you drop it anywhere in the clip. The crossfader under the decks cuts between A and B with an equal-power curve for transformer and chirp patterns, and each deck plays through its instrument's own channel, so your Sound Type, amp tone and effects come with it. Hit Full Screen for two-handed DJ moves.
Take your track with you
WAV & MP3
Render the whole song — or a single sample — to a downloadable WAV or MP3, encoded right in your browser.
Save Project
Save every setting and track to a project file: tempo, effects, sound type, amp tone, distortion and the timeline.
Load Project
Reload a project — or a shared settings file — any time. Recorded audio is stored in your browser.
Export Settings
Share your studio setup: Export Settings saves your tempo, tone, amp, effects and pitch/stretch as a small JSON file that other producers can load to match your sound.
Make your first track — 36 hands-on steps
Follow this walkthrough from a silent studio to a finished, exported song. The first seven get you a track fast; the rest go deeper into every studio feature, with diagrams of the parts that are easier to see than to describe. Each step points to the exact control on the main page.
Start the audio engine
Click Start Audio in the top transport to unlock the browser's sound. The status light turns to Ready, and Play, Record and the keyboard come alive.
Pick an instrument
Choose a sound in the Band Instruments rack — grand piano, drums, guitar, strings, brass or a synth. Your pick drives the piano keys, the pads and the Generate Music button.
Build a loop
Press Randomize Song for a full arrangement in a Style you choose, or play the on-screen piano and pads. Generate Music renders a melodic clip in the selected Style and Sound Type.
Whatever style you pick plays its own four-bar hook, and every hook is built the same way:
Arrange in the timeline
Drag a block to move it, drag either edge to trim or expand, and set a per-clip tempo. Duplicate a part with its copy button, or select it and press Ctrl+C then Ctrl+V to paste.
Keep it tight
Clips only sound inside their block. A sample now stops at the end of its region instead of ringing out over the empty bars that follow, so only the active music plays.
Record & shape the sound
Hit Record to capture a take over the loop; stopping opens the Export Music window. Shape the tone with Amp Tone, Distortion, the Effects Rack and the global Pitch / Stretch sliders.
Export or save
Download the finished mix as WAV or MP3, or Save Project to keep every setting and track so you can pick up right where you left off.
Choose a Sound Type
In Band Instruments, swap an instrument's real timbre for a synth voice — electronic, techno, synth pad, retro, FM and more. It reshapes both live playing and what you generate.
Dial an Amp Tone
Beside the instrument, pick an Amp Tone — drive plus a three-band EQ with 34 voicings from Classic Rock and Jazz to Metal and Lo-Fi. It colours every note through that channel.
Add guitar distortion
With the electric guitar selected, the Distortion menu adds sizes, angles, distances and directions — drive, bit-crush, space and stereo movement for a full guitar rig.
Open the Sample Sequence
Under Amp Tone, the Sample Sequence is a mini drum machine. Tap Add to layer several instruments as rows in one grid and program each independently.
Pick a sequence length
Use the Steps selector to make the pattern 8, 16 or 32 steps long. Changing length keeps whatever you have already programmed.
Insert drum tones
Click a drum pad — Kick, then Snare, then Hi-Hat — and each Add inserts that exact drum tone as its own row, so you build a kit one piece at a time.
Play chords into rows
Play a chord on any instrument (a pad or held keys) and the next Add inserts that exact chord as its own row — stack a C major and a G major piano row, a bassline and drums together.
Switch Style live
While the loop is playing, choose a new Style in the Loop Sequencer and the song switches to that artist's melody on the fly — the beat never stops, so you can audition styles seamlessly.
Generate an artist sample
Generate Music renders a clip in the chosen artist's style, picks a fresh tone and melody, and names it after one of that artist's real top songs — then drops it in your sample list.
Upload your own audio
In Sample Studio, upload a WAV or MP3. It saves to your browser and drops straight onto the timeline at bar 1, so every upload plays in sync with the song.
Record a sample
Rec Sample captures whatever the studio is playing into a new slot with its own fader and channel — perfect for bouncing a loop and re-sequencing it.
Record your microphone
Record MIC captures your microphone straight into a sample slot, so you can add vocals, claps or found sounds and treat them like any other instrument.
Bend pitch & time
The toolbar's Pitch and Stretch sliders drive PhaseVocoder.js: shift pitch by semitones while keeping length, or stretch length while keeping pitch — on samples and the export.
Balance the Mixer
Open the Mixer to set a fader, mute and solo per track. Solo a part to focus on it, or pull faders to blend the arrangement.
Sculpt with the Effects Rack
The master Effects Rack under the piano adds Reverb, Delay, Feedback, Chorus, Drive, Filter, Crush and Swing — the whole mix flows through it before your speakers.
Trim & expand clips
On the timeline, drag either edge of a block inward to shorten it, or outward to grow it — drag past the end and the song adds bars to make room automatically.
Move, copy & paste
Grab a block's header to slide it, use its copy button to duplicate, or select it and press Ctrl+C then Ctrl+V — the notes travel with the block.
Set the song length
In the Loop Sequencer, the Length menu sizes a new random song to Auto or 8–48 bars, and Add 4 Bars / Remove 4 resize the current one.
Export WAV or MP3
Render the whole song — or a single sample with Export Sample — to a downloadable WAV or MP3, encoded right in your browser.
Save & reload projects
Save Project writes every setting and track to a file; Load Project brings it all back. Recorded samples stay saved in your browser, ready for next time.
Scratch on two decks like a DJ
Turntable Scratching above Amp Tone gives you two motorised decks. Hit Play so a record spins at 33⅓, then grab the platter — it follows your hand, plays in reverse when you pull back and bends up to speed again when you let go. Cue drops the needle back at the start, and the crossfader cuts between A and B.
Import your own music onto a deck
Every deck has its own Import button, so you can put a different track on each one. MP3, WebM and WAV are decoded straight away, and a MIDI file is performed with the studio's own voices, because browsers cannot play MIDI on their own. Import to Both at the top takes two files at once — the first lands on deck A, the second on deck B. Generate Music cuts a fresh clip in the chosen Style onto both decks instead, and Clear All Music empties them.
Mix the decks
Each deck carries a full channel strip: Volume, a ±16% Pitch fader that really speeds the platter up or slows it down, a sweepable Filter — low-pass to the left, high-pass to the right — and Low / Mid / High EQ. Reverse spins the whole record backwards. Every reading updates live under its fader.
Find your spot in the track
Under every platter is a track slider with a running time. It follows the needle as the record turns, so you can see exactly where you are in the clip — and dragging it drops the needle somewhere else, which is far quicker than spinning the platter to hunt for a phrase. Pair it with Cue to snap straight back to the top.
Work offline & install the studio
Everything the studio needs — the audio engine, the icons, the fonts and every instrument recording — sits in the folder beside index.html, so the whole thing runs with the network switched off. Serve the folder over http://localhost or any https address and Chrome offers to install it: an Install App button appears in the top bar and the studio opens in its own window from your desktop.
Play it on a tablet
The studio works on touch as well as a mouse — the platters, piano keys and timeline clips all respond to a finger, and it stays compatible back to older tablets such as a 2015 iPad. Add it to your home screen and it opens full screen without browser chrome.
Share your settings
Hit Export Settings in the top bar to save your tempo, tone, amp, effects and pitch/stretch as a JSON file. Send it to a friend — they just Load Project to match your sound.
Pick a theme
The Theme menu in the top bar switches the whole studio between Dark, Grey and Light. Every colour — panels, faders, the timeline grid, even the waveform monitor — is repainted for the theme you choose, so nothing washes out. Your pick is remembered for next time.
Fold away what you are not using
Every area collapses. Click any panel heading — Transport, Band Instruments, Song Presets, Selected, Turntable Scratching, Sample Sequence, Pads & Keyboard, Effects Rack, Mixer, Loop Sequencer, even the Monitor with the meters and waveform — and it folds down to its title bar. Fold the parts you are not using and the part you are using fills the screen.