Barrel Organ - Barrel

Barrel

The pieces of music (or tunes) are encoded onto the barrel using metal pins and staples. Pins are used for short notes, and staples of varying lengths for longer notes. Each barrel usually carried several different tunes. Pinning such barrels was something of an art form, and the quality of the music produced by a barrel organ is largely a function of the quality of its pinning. This complex encoding of music was an early form of programming.

The organ barrels must be sturdy to maintain precise alignment over time, since they play the same programming role as music rolls and have to endure significant mechanical strain. Damage to the barrel, such as warpage, would have a direct (and usually detrimental) effect on the music produced.

The size of the barrel will depend on the number of notes in the organ and the length of the tune to be played. The more notes, the longer the barrel. The longer the tune, the greater the diameter.

Since the music is hard-coded onto the barrel, the only way for a barrel organ to play a different set of tunes is to replace the barrel with another one. While not a difficult operation, barrels are unwieldy and expensive, so many organ grinders only have one barrel for their instrument.