Accordion

Accordion, a hand-held musical instrument consisting of a bellows attached to two oblong frames, on which buttons and, in some types, pianolike keys are mounted. A person plays the accordion by drawing (stretching) and pushing (compressing) the bellows, causing air to pass over metal tabs called reeds. This airflow makes the reeds vibrate, which produces sounds. A player produces the various notes by depressing the buttons and keys. The reeds and buttons that control bass notes are on the player's left-hand side of the bellows, and the reeds and buttons or keys that control treble notes are on the right-hand side.

The two main types of accordion are single-action and double-action. In single-action accordions, each button produces two notes, one on the push and another on the draw. In double-action accordions, each key or button produces the same note on the push as on the draw. The most familiar type of accordion, the piano accordion, is a double-action accordion. The piano accordion has a row of pianolike keys instead of buttons on the right-hand side.

An accordionlike instrument called the Handäoline was invented in Berlin in the 1820s. Cyril Demian patented the first actual accordion in 1829 in Vienna. The earliest accordions had ten melody buttons and two bass buttons. Later versions added more buttons, enabling players to produce an even wider variety of notes and chords. The piano accordion was developed in the 1850s.

The concertina is a small, hexagonal instrument that is similar to the accordion. It is made in single-action and double-action versions. Sir Charles Wheatstone invented the concertina in 1829. He was inspired by the action of the sheng, an ancient Chinese mouth organ.