Near-mythical woodwind instrument pitched a full three octaves below the soprano clarinet, two octaves below the bass clarinet and one octave below the contrabass clarinet. Very possibly the largest woodwind instrument, comparable in size to behemoths such as the contrabassoon and the contrabass saxophone.

There is only one octocontrabass clarinet in existence, in the private collection of the LeBlanc family. Not surprisingly, I've never heard it, although I have seen a picture. One presumes it would have a sound somewhat recognizable as belonging to the clarinet family, although I can't be sure.

The lowest notes possible on an octocontrabass clarinet are almost mind-boggling to fathom. Consider that the frequency of the A above middle C is 440 Hz. On a soprano clarinet, a B-flat instrument, that turns out to be the B above middle C. The B below middle C (the lowest B on the instrument) is therefore at 220 Hz. The same fingering on a bass clarinet is an octave lower, or 110 Hz. On a contrabass, it's 55 Hz. On an octocontrabass, it would be 27.5 Hz. However, that's not even the lowest note on the clarinet. Frequencies approching 15 Hz would, by my calculation, be possible on such a low instrument. Listeners with above-normal hearing might even be able to distinguish the 15 individual pulses per second and hear the note as a "vibration" rather than a pitch.

One of my pipe dreams is to one day own an octocontrabass clarinet.