Make music.

No lessons needed.

Every note lands in keyDraw it, tap it — nothing sounds wrong
Made on your devicePlayed live, not played back
Save it as your ownThen record it on the beat
Coming soon to the App Store
22rooms of impossible shapes
9parts to mix
0musical training needed
Scroll
Before you touch a thing

22 rooms, 22 house tracks,

and any track plays in any room —

484
Pairings

Then twelve keys, minor or major, twelve chord progressions in each, and the tempo is yours to set. We stopped counting there. The number isn't the point. The point is that all of it is yours to change.

What we noticed

Most people never get to make a track.

Making music has usually meant years of lessons, or software that assumes you already know what a minor ninth is. The best part — hearing something you made come together — sits on the far side of all that. We didn't think it should.

So Calabi keeps the theory for you. The key, the chords and the notes the lead can play are worked out already; your part is deciding what sounds good. And while you play, a shape from real mathematics moves to what you make.

Six seconds of a Calabi–Yau room, as the app draws it.
What we did about it

The theory is built in.

Every room opens on a house track to start from, and the picture moves to it: the kick swells the shape, the chords change it, a fill breaks it apart until the crash brings it home. Then we handed you the tools to make it yours.

0

Wrong notes

Draw across the screen and the lead plays only notes from the track's key. Tap and you get the chord the track is on. Change the key and everything follows. You can't play a bum note.

9

Channels on the mixer

Kick, hats, clap, percussion, bass, arpeggio, hook, chords and lead — each with mute, solo, level, pattern and sound, and its own send to the echo and the reverb.

0

Loops or recordings, bar one

Every sound is made live on the device as it plays: the kick is a sine wave diving in pitch, the hats are six square waves at clashing pitches. The one recording is a grand piano. That's why key, tempo and sound change instantly.

And if you'd rather watch: DJ arranges the music for you and VJ plays the picture, so a room can run itself. Your hands always win — touch the filter or a mute and DJ leaves it to you for a while.

— Ricky Chopra, who made this

Don't take our word for it

This is what you play with.

No keyboard, no notes to learn. Your hands do three things on the picture, and behind them every part of the track has its own controls.

Drag up and downRides the filter — the big sweep over the synths, muffled to bright.
Draw side to sidePlays a lead in the track's key: low notes one way, high the other, none of them wrong.
TapPlays the chord the track is on.
The Quintic room playing Peak Hour, with the mixer open: level faders, mute and solo buttons, patterns and sounds for kick, hats, clap and percussion
The mixer: level, mute and solo for every part
The kick pattern panel over the Portal room, offering the track's own patterns alongside house, techno and breaks patterns
Patterns: the track's own, or house, techno and breaks
The Changes tray over the Tesseract room: chord progressions, how long each chord lasts, variation, fills and a Slow down move
Changes: the chords, and how often a fill turns the phrase

Real screens from the app, including a few of our own mixes.

From first tap to your own track

Start with ours. Finish with yours.

You never start from a blank page. Every room hands you a finished track, and everything in it is yours to change.

  1. Pick a roomIts track starts straight away. Any of the 22 tracks will play in any room.
  2. Play over itRide the filter, draw a lead, tap in chords. Every note lands in the track's key.
  3. Take it apartOpen the mixer: mute and solo any of the nine parts, set their levels, send them to the echo or the reverb.
  4. Change what it playsSwap a part's pattern for the track's own or for house, techno and breaks patterns. Change its drum kit or synth sound.
  5. Change the song itselfPick a key, minor or major, and one of twelve chord progressions. Set the tempo, the swing, and how hard the synths pump against the kick.
  6. Keep itSave it under a name and it's in your tracks, ready to load in any room. Then record it: it counts you in and starts on the beat, straight into your Photos.
Made on your device

Made live, as you play.

Every sound in Calabi is made live by your iPhone or iPad as it plays. There are no loops and no recorded samples, with one exception: the grand piano, which is a real concert grand. That's why the key, the tempo and every sound can change the instant you touch them.

The drums

The kick is a sine wave diving in pitch with a click on the front. The hats are six square waves at clashing pitches, filtered to a shimmer. The clap is noise struck four times a few milliseconds apart. Each kit changes the shape of each.

The synths

Saw, square, FM, organ, pluck and more, through a filter modelled on the classic analogue ones. The sub bass is a pure sine wave.

The chords

Voiced so the top note moves as little as possible from chord to chord, the way a keyboard player's hands would.

The space

An echo that bounces left and right in time with the track, a reverb, a chorus, a gentle compressor that glues the mix together, and a soft clip so it's loud without breaking up.

The House Piano is a concert grand recorded by the University of Iowa Electronic Music Studios, whose recordings may be used for any project. With thanks.

What's on the shelf

Twenty-two rooms, A to Z.

Each one a shape from mathematics, and each opening on its own track.

01

24-Cell

Four dimensions

The solid only four dimensions have — twenty-four octahedra — seeming to turn itself inside out.

Broken Signal 132 BPM
02

Boy

Projective plane

One side, no edge, no inside. Each chord turns it inside out about a point of its own.

Night Shift 126 BPM
03

Cubic

Calabi–Yau

Nine patches drawn as tens of thousands of points of light. The hats set it sparkling.

Echo Chamber 118 BPM
04

Gyroid

Minimal surface

Fly through a glass labyrinth that fills all of space; the chord bends it towards its kin.

Loop Hole 124 BPM
05

Harmonic

Calabi–Yau

Every chord a Calabi–Yau: a fifth, at 3:2, makes a 3-by-2 surface. The maths of the music is the maths of the picture.

Hands Up 124 BPM
06

Harmonograph

Victorian machine

A pendulum for every note of the chord. Consonant chords close into calm loops; dissonant ones wander.

Velvet 122 BPM
07

Hopf

Fibration

A circle at every point of space, each one linked through every other exactly once.

Lift Off 138 BPM
08

Julia

Fractal

An endless dive into a fractal; the chord's ratio picks how many arms it has.

Slow Burn 120 BPM
09

K3

Calabi–Yau

The shape string theory first curled its extra dimensions into: sixteen sheets of glass, four by four.

Cowbell Riot 118 BPM
10

Klein

Four dimensions

A bottle with no inside, turning through the fourth dimension. On a fill it splits into two Möbius strips.

Deep Water 132 BPM
11

Knots

Torus knots

Every interval in the chord as a glass knot. A fifth is a trefoil.

Glass Keys 118 BPM
12

Lasers

Light

A club's laser rig in haze, swung by the chords and flicked by the hats.

Future Soul 125 BPM
13

Lopsided

Calabi–Yau

Seven-fold one way, two-fold the other: fourteen patches in a lopsided knot, drawn in wire.

Squelch 130 BPM
14

Moiré

Op art

Two sets of fine lines, and a third pattern shimmering between them that's in neither.

Automaton 112 BPM
15

Particles

Chaos

A hundred thousand points pulled into strange attractors — Lorenz's butterfly among them — a new one each chord.

Long Road 128 BPM
16

Pearls

Möbius maps

Indra's pearls: circles pouring out of one glowing eye and into another, for ever.

Slow Motion 120 BPM
17

Portal

Polygons

Fly down a tunnel of frames shaped by the chord: a fifth a triangle, a major third a pentagon.

Concrete 132 BPM
18

Prism

Kaleidoscope

A projector gone strange: patterns split into red, green and blue and poured down a tunnel of their own trails.

Shuffle Room 125 BPM
19

Quintic

Calabi–Yau

The famous one: twenty-five sheets of glass folding through a fourth dimension. The kick swells it.

Peak Hour 126 BPM
20

Steiner

Circle chains

A chain of chrome pearls rolling for ever down a swerving tunnel of rings.

First Jack 120 BPM
21

Tesseract

Four dimensions

The four-dimensional cube. On a fill it unfolds into the cross of eight cubes Dalí painted.

Second Wave 134 BPM
22

Whirl

Polygons

Polygons inside polygons for ever, whirling into spirals as you play.

Sunday Soul 124 BPM
What it keeps

What you make stays on your device.

The tracks you save and the room settings you choose to keep live in the app's own storage. Recordings go to your photo library. That is the complete list.

Boy's surface in green glass above the mixer, with level faders, mutes and solos for kick, hats, clap and percussion
The mixer, open under Boy
Pearls, a spiral of coloured rings, with the sound settings tray along the bottom
Sound settings: track, tempo, key, chords
Whirl's coloured polygons with the hats sound panel open, offering kits called Standard, Metal, Crisp, Soft and Hard
Choosing a kit for the hats

We don't collect it. We don't see it. There is no server for it to go to.

Calabi makes no network connections at all: no account, no analytics, no advertising, no crash-reporting service and no third-party SDKs. Apple handles the purchase, so we never see your name or payment details. If you've chosen to share analytics with developers in your device's settings, Apple may pass us anonymous, aggregate figures — that's Apple's switch, and you can turn it off.

No account, no sign-in

Open it and play. There is nothing to register and nothing to log in to.

It never listens

Calabi doesn't use the microphone. The music is generated on the device, not captured.

Recordings are yours

Clips go to your photo library, in a Calabi album. The app asks to add there and to find that album again; it doesn't look at your other photos, and keeps no copy.

No connection needed

Every sound and every picture is made on your iPhone or iPad, so nothing is streamed or downloaded, and it plays anywhere.

Delete it in two taps

ⓘ → Your data deletes all your tracks or resets every room. Deleting the app removes the rest; recordings stay in Photos until you delete them.

Nothing follows you out

No advertising, no tracking, nothing that profiles you. The full policy is here.

Bigger screens

iPhone, iPad, and the wall.

One app for iPhone and iPad, and on iPad it turns any way round. Plug either into a TV or projector and the room's picture fills that screen at the screen's own resolution — up to 4K — while the controls stay in your hands.

The Calabi shelf on iPad: a grid of room tiles from 24-Cell to Whirl, each with its name and a line about the shape
The shelf on iPad
Boy's surface in blue glass above the full nine-channel mixer on iPad
Boy, with all nine channels in view
A violet tesseract on iPad with the picture settings tray open
Tesseract, with the picture's own settings

Not a mirror

A connected screen gets a window of its own, drawn for that screen, rather than a copy of your device with the buttons on it. You'll need a cable or adapter that carries video, such as USB-C to HDMI — most charging cables don't.

It can run itself

DJ arranges the track in phrases of eight or sixteen bars — parts in, a breakdown, a snare roll, the drop. VJ moves the room's settings on every phrase. Turn both on and walk away.

Record on the beat

Tap Record and it counts in — three, two, one — then starts the music from the top of a bar, so every clip begins on the beat, with the app's own music on it.

Keeps playing when locked

The music carries on with the screen off, the way any music app does.

The offer

Every room. Every track. Once.

All twenty-two rooms, all twenty-two tracks, the full mixer, recording and big screens — £2.99, once, from the App Store. No subscription, nothing to buy inside the app, nothing that renews.

22RoomsEach with its own track
9Mixer channelsMute, solo, pattern, sound
12Chord progressionsIn any key, minor or major
£2.99Once, for all of itNo subscription, nothing renews
The Calabi shelf on iPhone: room tiles for 24-Cell, Boy, Cubic, Gyroid, Harmonic and Harmonograph
Julia: a rainbow fractal spiralling into its centre, playing Slow Burn at 120 BPM
Tesseract: a glowing four-dimensional cube, playing Second Wave at 134 BPM in D minor

Real screens, not mock-ups.

No subscription. Nothing renews.

Pay once. That's the whole deal.

£2.99 once, and after that there is nothing else to buy.

£2.99
Once. Not a subscription

One payment

Apple handles the purchase and any refund. We never see your payment details.

Everything
Included from the start

Every room and every track

  • All 22 rooms and their 22 tracks
  • The mixer, sound and picture settings
  • Saving your own tracks, and recording to Photos
  • iPhone, iPad and a connected TV
Nothing
Else to buy, ever

No in-app purchases

No subscription, no packs, no adverts, and no rooms waiting behind a paywall.

Needs an iPhone or iPad on iOS 17 or later — and nothing else.

Prices shown in GBP. The App Store sets its own price in each territory, so yours may differ — Apple shows it in your currency before you pay.

Please read before you play. The rooms flash, spin and change direction quickly, in strong colour and hard contrast. If you have epilepsy or have had a seizure, talk to your doctor before using Calabi. The app shows this warning each time it opens; the full notes are in the terms.
Coming soon to the App Store

Questions: hello@mixudg.com, or read the support page.