INSTRUMENT GUIDE
Accordion
An accordion is a portable free-reed instrument. Moving its bellows sends air through metal reeds; keys or buttons select the notes. The melody side may have piano keys or buttons, while the other side commonly provides bass notes and chords. The diagrams here compare three real keyboard layouts rather than one supposed universal accordion.
How does an accordion make sound?
Pressing a key or button opens a path for air from the bellows to a reed. The moving air makes the reed vibrate. Bellows pressure shapes the loudness and phrasing, while the keyboard selects the pitch. The sound mechanism is shared across many accordion types even though their keyboards differ.
See the illustrated sound mechanism →Piano, chromatic button and diatonic accordions
The shape of the melody keyboard is the first distinction to look for. These diagrams reproduce the named reference layouts; the number of keys, range and button positions can differ on other models.
Piano accordion
The HOHNER Bravo II 48 chart has 26 piano keys for the melody and 48 bass buttons. The same melody key sounds the same pitch when the bellows change direction.
Reference keyboard chart: HOHNER Bravo II 48Chromatic button accordion
The HOHNER Nova II 60A chart uses C-system melody buttons. Like a piano accordion, each melody button keeps its pitch on push and pull; the button pattern differs from piano keys.
Reference keyboard chart: HOHNER Nova II 60ADiatonic button accordion
The HOHNER Erica G/C chart has two melody rows and 21 buttons. Many of those buttons give different notes when the bellows are pushed and pulled, so direction is part of choosing a note.
Reference keyboard chart: HOHNER Erica G/CDoes the note change on push and pull?
It depends on the system. The piano and chromatic button examples above are unisonoric: a key or button keeps its note in both directions. The Erica G/C is bisonoric: many melody buttons have one push note and another pull note. Look at the two notes shown for a button in its diagram before assuming how another diatonic model works.
What does the left hand play?
On standard bass accordions, left-hand buttons provide individual bass notes and preset chords. A free-bass layout instead gives individual pitches across the left-hand keyboard; some converter instruments can switch between the systems. The left-hand guide shows how bass and chord buttons relate to one another.
Explore the left-hand bass guide →How is it different from a concertina or bandoneon?
Concertinas and bandoneons also use bellows and free reeds, but their buttons are arranged at both ends. A common tango bandoneon has single-note buttons on its left side rather than the preset chord buttons of a standard bass accordion. The full guide compares the three families and their layouts.
Compare all three instrument families →