It is played by compressing or expanding a bellows whilst 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.[notes 1]
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 is often used in folk music in Europe, North America and South America. It is commonly associated with busking. Some popular music acts also make use of the instrument. Additionally, the accordion is sometimes used in both solo and orchestra performances of classical music.
The oldest name for this group of instruments is actually harmonika, from the Greek harmonikos, meaning harmonic, musical. Today, native versions of the name accordion are more common. These names are a reference to the type of accordion patented by Cyrill Demian, which concerned “automatically coupled chords on the bass side”.
A concertina is a free-reed musical instrument, like the various accordions and the harmonica. It has a bellows and buttons typically on both ends of it. When pressed, the buttons travel in the same direction as the bellows, unlike accordion buttons which travel perpendicularly to it. Also, each button produces one note, while accordions typically can produce chords with a single button.
The concertina was developed in England and Germany, probably independently. The English version was invented in 1829 by Sir Charles Wheatstone and a patent for an improved version was filed by him in 1844. The German version was announced in 1834 by Carl Friedrich Uhlig.
