The accordion is a portable box-shaped musical instrument of the hand-held bellows-driven free-reed aerophone family, sometimes referred to as a squeezebox. A person who plays the accordion is called an accordionist. It is played by compressing or expanding a bellows, while pressing buttons or keys, causing valves called pallets to open which allow air to flow across strips of brass or steel called reeds that vibrate to produce sound inside the body.
The instrument is sometimes considered a "one-man-band", as it needs no accompanying instrument; the performer normally plays the melody on buttons or keys on the right-hand manual, and the accompaniment—consisting of bass and pre-set chord buttons—on the left-hand manual.
The accordion's body consists of two wood boxes joined together by a bellows, respectively housing reed chambers for the right- and left-hand manuals. Each side has grilles in order to facilitate the transmission of air in and out of the instrument, and to allow the sound to better project. The grille for the right-hand manual is usually larger and is often shaped for decorative purposes. The right-hand manual is normally used for playing the melody and the left-hand manual for playing the accompaniment, however skilled players can reverse these roles.
The size and weight of an accordion varies depending on its type, layout and playing range, which can be as small as to have only two rows of basses and a single octave on the right-hand manual, for children, to the standard 120 bass accordion and through to large and heavy 160 bass button free-bass converter models.
