Akordify

Play the song's chords with your bare hands

New on every song page

Gesture Synth turns your webcam into an instrument. Your left hand chooses the chord, your right hand controls volume, voicing and tone, and everything is tuned to the key of the song you have open. No guitar, no keyboard, no cables.

Pick a song and play

Runs in your browser. The camera image is processed on your device and is never uploaded.

Three steps to your first chord

  1. Open a song and press Gesture Synth: The button sits in the toolbar of every song page. The song pauses, the instrument opens full screen and it already knows the key.
  2. Allow the camera and turn on sound: Sit about an arm's length from the webcam in good light. Once both hands appear on screen with their tracking dots, you are ready.
  3. Show fingers and play: Left hand: one finger is chord I, two fingers chord II and so on. Right hand: lift it to make the chord louder, add fingers for richer voicings.

Hear the chords before you raise a hand

These pads are the seven chords of C major, exactly as your left hand plays them. Click a pad to hear it with the same synth that Gesture Synth uses, switch between major and minor, and try the four right-hand voicings.

Tip: play I, V, vi, IV in a row. That is the progression behind hundreds of pop songs.

The gesture atlas

Every shape the instrument understands, on one screen. Learn the left hand first. The right hand only adds colour.

Left hand: which chord

Count extended fingers including the thumb. Two special shapes cover the sixth and seventh chord.

Right hand: how it sounds

Height is volume, a fist is silence. Raised fingers (without the thumb) pick the voicing.

Wrist tilt and thumb

Always in the key of the song

When you open Gesture Synth from a song, the instrument takes over that song's key, including any transposition you set in the player. Your fingers count scale degrees, so the same hand shapes work for every song. Minor songs are played from their relative major: in a song in A minor, the A minor chord is the sixth degree of C major. The strip at the bottom of the screen always shows the real chord names.

Example: a song in A minor: Am (vi), F (IV), C (I), G (V).

Four ways to play

Your camera stays yours

Hand tracking runs directly in your browser. The tracking model is downloaded once, and each video frame is analysed on your device to find 21 points on every hand. Akordify does not upload, record or store your camera image. When you close Gesture Synth, the camera turns off.

The complete guide to Gesture Synth

What Gesture Synth is and why it exists

Gesture Synth is a musical instrument that you play in the air. It watches your hands through an ordinary webcam and turns their shapes into chords. Your left hand decides which chord sounds, your right hand decides how loud it is, how full the voicing is and how bright the tone is. There is nothing to plug in and nothing to buy: a laptop with a camera and a pair of speakers or headphones are enough.

The idea is not to replace the guitar or the piano. It is to take away everything that stands between you and the harmony of a song for a moment. On a guitar, a new chord means learning a fingering, building strength and coordinating two hands before you hear anything good. In Gesture Synth, the chord is there the moment you show the right number of fingers. That makes it ideal for understanding how a song is built, for hearing why a progression works, and for simply having fun with music when no instrument is at hand.

Because Gesture Synth lives on every song page of Akordify, it always starts in the key of the song you are looking at. You can listen to a song, open the instrument, and immediately play along with its chords using the same hand shapes you would use in any other key.

How the camera reads your hands

When you allow camera access, Gesture Synth loads a hand tracking model in your browser. Every frame of video is analysed on your own device, and the model finds 21 landmarks on each hand: the wrist, the joints of every finger and the fingertips. From those points, the instrument works out which fingers are raised, where the thumb is pointing, how high the hand is in the picture and how much the wrist is tilted.

The camera image is never uploaded or stored. The only thing downloaded is the tracking model itself, which your browser caches. When you close Gesture Synth, the camera is switched off.

To keep chords from flickering when a finger is halfway up, the instrument uses a short stabiliser. A new hand shape must be held for about a tenth of a second before the chord changes, and a brief tracking dropout keeps the last chord sounding. In practice this feels instant, but it filters out the accidental in-between shapes that happen when you move from one gesture to the next.

The view on screen is mirrored, like a mirror in the bathroom. The hand you see on the left side of the screen is your left hand. That hand always chooses the chord, and the hand on the right side always shapes the sound.

The left hand: seven chords of a key

Every major key contains seven basic chords, one built on each note of its scale. Musicians label them with Roman numerals from I to VII. In C major they are C, D minor, E minor, F, G, A minor and B diminished. Gesture Synth maps these seven scale degrees onto your left hand:

One to five fingers play degrees I to V. Count every extended finger, including the thumb. One finger is the tonic (I), two fingers the supertonic (II), three the mediant (III), four the subdominant (IV) and an open hand with all five fingers the dominant (V).

Index and pinky raised together, like the classic rock sign, play degree VI. Index, pinky and thumb together play degree VII.

The wrist tilt of the left hand decides between major and minor. Keep the hand upright or let it lean inwards towards the centre of the screen and the chord is major. Lean it outwards and the chord turns minor. This means you can play any degree in both forms. The song decides which form is correct: in a typical major key, I, IV and V are major, while II, III and VI are minor. If you would rather not think about tilt, the settings let you lock the left hand to always major or always minor.

At the bottom of the screen, a strip of eight pads shows the scale of the current key with real note names, the Roman numeral for each degree and the gesture that plays it. The pad you are playing lights up in its own colour. Every degree has a colour that stays the same in the waves, the beat grid and the play along targets, so after a while you start recognising chords by colour as well as by sound.

The right hand: volume, voicing and tone

The right hand is your expression. Its height controls the volume: lift it to play louder, lower it for a quiet pad, close it into a fist to stop the sound completely.

Raised fingers on the right hand, not counting the thumb, choose the voicing, which is the way the chord's notes are stacked:

One finger plays a plain triad, spread out with the root, the fifth, the octave and the third on top. Two fingers play the first inversion, with the third in the bass, which sounds lighter and leads smoothly into neighbouring chords. Three fingers add the seventh: a dreamy major seventh on major chords or a soft minor seventh on minor chords. Four fingers play the tense seventh chords: a dominant seventh on major chords, the sound that pulls strongly towards the next chord, and a diminished seventh on minor chords.

Tilting the right wrist sweeps a filter. Lean one way and the sound becomes darker and rounder, lean the other way and it opens up into a bright, slightly resonant tone. Sticking the right thumb out drops the whole chord by one octave, which gives a heavier, bass-rich sound.

If four voicings are too much at first, set the right hand to a fixed voicing in the settings. Then the right hand only controls volume and tone, and the left hand does all the harmonic work.

Why everything is in the key of the song

Gesture Synth reads the key of the song you opened it from, including any transposition you set in the player. The degree numbers on your fingers are always relative to that key. This is exactly how working musicians think: they say "it goes one, five, six, four" instead of naming each chord, because the numbers stay the same in every key.

Songs in a minor key are played from their relative major, which shares the same notes. A song in A minor uses the chords of C major, and its home chord, A minor, sits on degree VI. A typical minor song with the chords Am, F, C and G is therefore played as VI minor, IV, I and V. The instrument tells you this in the header, and the scale strip shows real chord names, so you never have to do the conversion in your head.

Some songs borrow chords from outside their key. A song in C major might use a B flat or an E major chord for colour. Gesture Synth marks such chords clearly in play along mode and lets you skip them, because they cannot be formed from the seven degrees of the key. If you want to explore a different key, you can override the key in the settings at any time.

Play along with the song

The play along mode turns the real chord progression of the song into a series of targets. For each chord you see its name, its Roman numeral and the exact hand shapes: which fingers to raise on the left hand, whether to tilt it, and how many fingers the right hand needs for that voicing. The next few chords are shown on the side so you can prepare.

While play along is open, the instrument only produces sound when your gesture matches the target. This is deliberate: it gives you immediate, honest feedback without any score screen getting in the way.

Wait for me mode moves to the next chord once you have held the current one for a moment. It is the best way to learn a new progression, because you set the pace. In tempo mode follows the beat of the song: each chord lasts as many beats as it does in the recording, and the chart moves on whether you are ready or not. You can slow it down to 75 or 50 percent and switch on a metronome with adjustable volume. The clock starts with your first correct chord, so you are never chasing it from the first second.

At the end you see how many chords you hit. Try the same song again a day later and you will notice how quickly the shapes become automatic.

Theremin mode

The theremin was one of the first electronic instruments, invented by Leon Theremin around 1920. Its player never touches it: one hand moves near an antenna to change the pitch, the other near a loop to change the volume. Gesture Synth's theremin mode borrows that idea. Your right hand height sets the pitch continuously, from a deep bass of about 65 hertz up to a high whistle above 1,000 hertz, and your left hand height sets the volume.

Because the pitch is continuous, the theremin is a great ear trainer. Try to find the first note of a melody you know, then the next. Small, slow movements work better than large ones, and resting your elbows on the table helps a lot with control.

Loop recorder: build your own backing track

The loop recorder captures what you play and repeats it, so you can stack parts on top of each other. Set the tempo, either by typing a number or by tapping a few beats on the Tap button or the Space bar, choose a length of one to eight bars and a time signature, then press Record. After a one-bar count-in with a metronome, everything you play is recorded on the selected track.

There are four tracks. When one finishes, the next empty track is selected automatically, so you can record a chord track, then a bass line with the thumb octave, then a theremin melody on top. Each track has its own volume, mute and solo.

Below the controls, a beat grid shows every sixteenth note of the loop. Recorded steps light up in the colour of their chord. Click a step to switch it off or on again, which is a quick way to turn a held chord into a rhythmic pattern. With the chord palette, you can even paint chords of the key into empty steps with the mouse.

The metronome offers four sounds (click, wood, beep and hi-hat) and its own volume. When the loop sounds the way you want, download it as an audio file and share it, or use it as a backing track for guitar or singing practice.

Setting up for reliable tracking

Most problems with hand tracking come from the room, not the instrument. A few simple habits make a big difference:

Light. Face a window or a lamp. A bright window behind you turns your hands into silhouettes and makes fingers hard to see.

Distance. Sit about an arm's length from the camera. Both hands should fit in the picture with some space around them when you raise them to chest height.

Background. A calm, plain background helps. Busy patterns or another person in the frame can confuse the tracker.

Palms to the camera. Hold your hands with the palms facing the screen and fingers pointing upwards. Finger counting works best this way.

Sound. Headphones or decent speakers make the sound much richer than tiny laptop speakers, especially the bass when you use the thumb octave.

Gesture Synth works best in a current desktop browser such as Chrome or Edge on a computer with a webcam. It also runs on many tablets and phones with a front camera, but the bigger screen of a laptop makes the gesture guide and the loop recorder far easier to use.

What you learn by playing with your hands

Gesture Synth looks like a toy at first, but it teaches some of the most useful ideas in music. The first is degree thinking. Once you know that a song goes I, V, VI minor, IV, you know it in every key, and you can transfer it straight to guitar, piano or ukulele. The second is hearing function. After a few sessions you start to feel the pull of the dominant towards the tonic, the soft melancholy of the sixth degree and the open sound of the fourth.

You also learn the most common progressions by heart. I, V, VI minor, IV powers a huge number of pop songs. II minor, V, I is the backbone of jazz. I, IV, V is the twelve bar blues. VI minor, IV, I, V is the same pop progression starting from its minor chord, which makes it sound more emotional. Try each of them with your hands and listen to how different they feel.

Finally, Gesture Synth helps with chord colour. Switching between a triad, a seventh and an inversion with one finger makes it easy to hear what each extension adds, something that takes much longer to explore on a real instrument.

Your first fifteen minutes

Here is a short routine to get comfortable:

Minutes 1 to 3. Turn on Chords mode, keep the right hand at chest height with one finger raised, and count from one to five fingers on the left hand. Listen to how the chords climb the scale.

Minutes 4 to 6. Add the rock sign for VI and tilt the left hand outwards to make it minor. Play I, V, VI minor, IV slowly, four times in a row.

Minutes 7 to 9. Keep the same progression and change only the right hand: one finger, then three fingers, then a fist on the last beat for a clean stop.

Minutes 10 to 12. Open Play the song in Wait for me mode and work through the song you opened. Do not worry about speed.

Minutes 13 to 15. Record the progression on track one of the loop recorder, switch to theremin mode and try to improvise a melody over it on track two.

Troubleshooting

The instrument does not see my hands. Check the light and the distance first. Make sure both hands are fully in the picture, palms facing the camera.

The chord flickers between two degrees. A finger is probably half raised. Make the shapes clearer: fingers fully up or fully closed. The thumb is the most common culprit, so decide clearly whether it is in or out.

I get minor when I want major. Keep the left hand upright or lean it slightly inwards. If tilt keeps getting in the way, lock the left hand to always major in the settings.

There is no sound. Click the start button to turn on sound, check that the right hand is visible and not a fist, and raise it higher. In play along mode, sound only plays when your chord matches the target.

The camera is blocked. Allow camera access for Akordify in your browser's site settings and reload the page. If another app is using the webcam, close it first.

Questions about Gesture Synth

Do I need any special hardware?

No. A computer with a webcam and speakers or headphones is enough. Gesture Synth runs in the browser and does not need any extra device, controller or software installation.

Is my camera video uploaded anywhere?

No. Hand tracking runs on your device inside the browser. Only the tracking model is downloaded. Akordify does not upload, record or store your camera image, and the camera turns off when you close Gesture Synth.

Which browsers work best?

A current version of Chrome or Edge on a desktop or laptop gives the smoothest experience. Other modern browsers with camera support usually work too.

Can I use it on a phone or tablet?

Often yes, if the device has a front camera and the browser allows camera access. A laptop screen is more comfortable because both hands, the scale guide and the loop recorder fit on it at once.

Do I need to know music theory?

No. You only count fingers. The scale strip shows the real chord names, and play along mode shows the exact hand shapes for every chord of the song. The theory comes naturally while you play.

Why does a song in A minor show C major?

Minor keys are played from their relative major, which uses the same notes. In A minor, the A minor chord is the sixth degree of C major, so a progression like Am, F, C, G becomes VI minor, IV, I, V.

Can I record what I play?

Yes. The loop recorder captures up to four tracks over a metronome, lets you edit single steps in a beat grid and downloads the finished loop as an audio file.

Will this replace learning guitar or piano?

No, and it is not meant to. It is a fast way to understand and hear a song's harmony. The degree numbers you learn transfer directly to guitar, piano and ukulele, which you can practise on the same song page.

Your hands already know how to count. Let them play.

Open any song on Akordify, press Gesture Synth and play its chords in the air, in its own key, in a few seconds.

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