What’s nearly 12 feet tall, made of wood, and capable of producing a sound so low that most human beings can’t even hear it? That would be the octobass, the largest string instrument ever brought into existence. Though its curves and angles follow the familiar silhouette of its smaller stringed relatives (violins, violas, cellos, etc.), the octobass stands at a gargantuan 11 feet, 5 inches—so high, even a professional basketball player would have to stand on a platform to reach the instrument’s neck.

In addition to its recognizable shape, the octobass shares with other string instruments the same mechanisms for producing sound; a player holds down certain strings in a particular pattern to modify their pitch, then draws out the notes by plucking, strumming, or bowing those strings. However, whereas a violin can be scaled down to half- or three-quarter-size for a small child unable to stretch their fingers to reach all the frets, no aspiring octobass player can scale themselves up to accommodate the total distance of its fingerboard. Instead, the octobassist must become familiar with a series of levers attached to mechanisms that press the strings down, which they operate while simultaneously handling a bow that’s shorter, but much heavier than a typical bass bow. When legendary French luthier Jean-Baptiste Vuillaume constructed the original “octobasse” in 1850, it was considered a two-player instrument, with one musician assigned to the levers and another to the bow, both working to produce a single sound.

It tunes to two full octaves below a cello and one octave below a standard double bass or the lowest note on a piano, and its range extends down to a C note pitched at 16 hertz—lower than the normal human hearing range, which bottoms out at about 20 hertz. Colin Pearson, curator of the Musical Instrument Museum (MIM) in Phoenix, Arizona, explains the value of such an apparently un-musical instrument in a way that makes it seem like a very expensive science fair project: “It’s wonderful for demonstrating how sound waves work, and how a string vibrates. These strings are so large and so massive that the vibrations are slow enough for us to actually see them.”

Despite Vuillaume’s intention for the octobass to take its rightful place among other members of a traditional orchestra, modern uses of the instrument are few and far between, in part due to its scarcity. Vuillaume built three models of his massive invention, and today, only three playable replicas exist around the world: the one in Phoenix, another in Paris, and a third newly built in 2015, which debuted with an original composition for octobass and violin at Oslo’s Only Connect Festival of Sound. Nico Abondolo, principal bass player of the LA Chamber Orchestra and favored bassist of Hollywood composers like Hans Zimmer, says that his time experimenting with MIM’s octobass was “a surreal experience.”

While it holds a certain fascination, the octobass won’t be making a resurgence in popularity anytime soon. It is, however, perfectly suited for playing one song in particular: the theme song from 1975 thriller Jaws.

[h/t Open Culture]

Banner images via YouTube.