Two hands and a bellows
An accordion is two keyboards joined by a bellows. The treble keyboard on top is for the right hand and the melody: 41 piano keys from F3 to A6, the range of a standard full-size accordion. The bass buttons at the bottom are for the left hand, and most of them play a whole chord. The bellows across the middle are the left arm: every reed on the instrument is fed by that one air supply, so nothing sounds unless it moves.
That is why this page draws both hands at once. Play a melody on the keys with one hand and tap the bass with the other — or, on a computer, play the letters and the number row together — and you are playing the instrument the way it is played.
How to play it
Hold a key to sound it and let go to stop: an accordion note lasts exactly as long as the key is down and the bellows are moving. Slide along the keys without lifting to run from note to note on one breath of the bellows.
With Auto air on, the bellows breathe for you and every key sounds at a steady pressure, which is the easiest way to start. Switch to Bellows by hand and it becomes the real thing: hold a key, then drag the pleated strip sideways. Faster is louder and brighter; stop and the note stops; reach the end of the bellows and you have to turn them round. Every turn dips every sounding note for a moment — accordionists do it on purpose, fast and rhythmic, and call it the bellows shake.
On a computer keyboard the treble is laid out like a piano: A is middle C and the home row runs up the white keys to ', with W E T Y U O P as the black keys. The bottom row Z to / plays ten bass notes from E♭ to F♯, and the number row plays their major chords — so V then 4 is C bass, C chord. Hold Shift for the counterbass and the minor chords. Space turns the bellows; in By-hand mode, holding it moves them.
The Stradella bass, button by button
Every column of bass buttons belongs to one note, and the columns run round the circle of fifths: F, C and G are neighbours, and so are the three chords almost every simple song needs. Going away from the bellows, each column has up to six buttons. Here they are for C:
| Row | The C button plays |
|---|---|
| Counterbass | E — the note a major third above C |
| Bass | C, in two octaves |
| Major | C E G |
| Minor | C E♭ G |
| Seventh | C E B♭ — no fifth |
| Diminished | C E♭ A — no fifth |
Two things surprise people. The chords are all voiced inside one octave, F♯3 to F4, because every chord button shares the same twelve chord reeds — a C chord and a B chord are the same size. And the seventh and diminished chords have no fifth: the bass note underneath supplies it, and a player who wants a fuller chord presses two buttons at once. The C bass button is marked with a dimple, and the A♭ and E four columns either side of it with a ring, so a hand can find its place without looking; the page draws them the same way.
The size menu over the bass changes how many buttons the accordion has. Smaller accordions keep the columns nearest C and drop rows:
| Size | Columns | Rows |
|---|---|---|
| 12 bass | 6, B♭ to A | bass, major |
| 24 bass | 8, E♭ to E | bass, major, minor |
| 48 bass | 8, E♭ to E | counterbass, bass, major, minor, seventh, diminished |
| 72 bass | 12, D♭ to F♯ | counterbass, bass, major, minor, seventh, diminished |
| 96 bass | 16, C♭ to G♯ | counterbass, bass, major, minor, seventh, diminished |
| 120 bass | 20, B𝄫 to A♯ | counterbass, bass, major, minor, seventh, diminished |
Registers: which reeds sound
The row of switches above the keys is the treble register. This accordion has four sets of reeds, the common full-size layout: one an octave down (16′), two at pitch (8′) and one an octave up (4′). Each switch opens a combination, and its symbol shows which — a circle split into three bands, with a dot for each set of reeds: top for 4′, middle for 8′, bottom for 16′.
| Register | Reeds |
|---|---|
| Master | 4′+8′+8′+16′ |
| Musette | 4′+8′+8′ |
| Violin | 8′+8′ |
| Clarinet | 8′ |
| Bassoon | 16′ |
| Piccolo | 4′ |
| Oboe | 4′+8′ |
| Bandoneon | 8′+16′ |
| Accordion | 8′+8′+16′ |
| Organ | 4′+16′ |
| Harmonium | 4′+8′+16′ |
The registers with two 8′ reeds — violin, musette, accordion and master — are the ones that waver. The second reed is tuned a few cents away from the first, and the two beat against each other. How far apart is the Tremolo menu, and it is a matter of style: dry (0 cents), swing (4 cents), american (10 cents) and french musette (20 cents). Hold a chord on the violin register and step through them to hear a jazz accordion turn into a Paris café.
Button accordions: C-system and B-system
The keyboard chips above the instrument swap the right hand for a chromatic button keyboard. Along each row every button is a minor third above the last; each row is a semitone from the one beside it, so a chromatic scale runs straight across the rows on a diagonal, and every scale has the same shape in every key. Rows 4 and 5 repeat rows 1 and 2, which gives the fingers a choice. In the C-system — the European standard — C, E♭, F♯ and A sit on the outer row. The B-system — the Russian bayan — is its mirror: B, D, F and A♭ on the outer row, and the semitones climbing the other way. Both are drawn over the same notes as the piano keyboard, so you can compare them key for key.
The diatonic box: a different note on the push and the pull
The last chip is a one-row diatonic accordion, the Cajun box. It has 10 buttons and each one plays two notes: pushing, every button gives a note of the key’s major chord (in C: C4, E4 and G4 from the third button up), and pulling gives the notes in between (D4, F4, A4 and B4). So the bellows direction is part of the note, and a melody is a dance between the two. Each button shows both notes, the live one bright; in practice mode the button to press lights up and the bellows button says which way to go next. Turn the bellows while holding a button and the note under your finger changes, exactly as on the real box.
Its left hand is two buttons, bass and chord: the key’s own chord on the push and the chord a fifth above on the pull, C and G in C. The key menu moves the whole box — a D box is a C box a whole step up, reed for reed. Two-row boxes (D/G, B/C) are not drawn yet: no chart of their buttons was found that this page could check itself against.
Songs to play
Press Play a song under the instrument. On the piano and button keyboards the accordion plays 22 of the 22 public-domain songs here in C; the one-row box in C plays 22, because it has no sharps or flats at all. Play plays a song for you, lighting each key as it sounds; Practice waits on the next note; Play along closes a ring on each note in time with the music. The songs are the right hand only, so the left hand is free to add the bass. Record under the keyboard captures both hands.
More instruments you can play here
The online harmonica is the accordion’s smaller cousin — the same free reeds, blown and drawn instead of pushed and pulled. Got a real accordion that sounds sour? The accordion tuner listens through your microphone and explains which register to check each reed on.
Frequently asked questions
How do you play the accordion?
The right hand plays the melody on the treble keyboard, the left hand plays the bass buttons, and the left arm opens and closes the bellows, which is what makes any of it sound. The classic beginner pattern is oom-pah: the bass note of the chord on the beat, the chord button beside it on the off-beat, while the right hand plays the tune. On this page tap a bass button, then the major button just below it, and the C bass and the C major chord are exactly that pair.
How do the bass buttons on an accordion work?
A standard accordion uses the Stradella system: each column of buttons belongs to one note, and the columns go round the circle of fifths, so the three chords a song in C needs — C, F and G — sit side by side. The two rows nearest the bellows play single bass notes (the counterbass row gives the note a major third above the bass row); the rows beyond them play whole chords with one button: major, minor, seventh and diminished. A 120-bass accordion has twenty columns, from B𝄫 to A♯, and six rows.
What do the register switches on an accordion do?
They choose which sets of reeds each key sounds. Most accordions have several reeds per key: one an octave low (16′, “bassoon”), one or two at pitch (8′, “clarinet”), one an octave high (4′, “piccolo”). Each switch opens a combination, and the symbol printed on it — a circle with a dot for each reed set — says which. Two reeds at pitch tuned a few cents apart is the wavering musette sound; all of them together is “master”, the fullest the instrument can play.
What is the difference between a piano accordion and a button accordion?
Only the right hand. A piano accordion has piano keys; a chromatic button accordion has three to five rows of round buttons laid out so a chromatic scale runs diagonally across the rows and every key signature has the same shape. Buttons fit more notes into a smaller keyboard, which is why button players reach wider. The bass side is usually the same Stradella system on both. A diatonic button accordion, a melodeon, is a different instrument: each button plays two notes, one on the push and one on the pull.
Is this a recording of a real accordion?
No. Each note is built as you play it, from what an accordion physically is: steel reeds chopping the air into a pulse, so every harmonic is present; up to four reeds per key, an octave apart or a few cents apart, chosen by the register; and one bellows feeding all of them, so squeezing harder makes every held note louder and brighter at once. It is modelled rather than measured from one instrument, and the first note sounds the moment you touch a key — there is nothing to download.