Have you ever heard of classical music’s lowest (and rarest) string instrument? It’s called the octobass (a.k.a. octobasse) and was built in 1850 by French instrument maker Jean-Baptiste Vuillaume. It is tuned two octaves below a cello and stands a 12-feet tall. With the human range of hearing starting at 64 Hz, it’s lowest note (C: 16 Hz) is heard as more of a rumble rather than a perceivable pitch. (Perfect for playing the Jaws theme!)
The player must stand on a stool and operate hand and foot-activated levers and pedals to change the pitch. The blow is specially made for the octobass and is equally massive with leather grips. There are only two originals in world, with one found at the Musical Instrument Museum in Phoenix, Arizona.
Though it was never adopted on a broad scale, Hector Berlioz was very fond of the instrument and wrote about it in his famous Orchestration Treatise first published in 1844.
For a taste of the octobass playing J.S. Bach, see below: