What is "octoban"

Octobans, also known as tube toms, are deep, small diameter, single-head tom-toms. Octobans were originally grouped in melodically-tuned sets of eight, hence the name, in reference to octave and from octo meaning "eight".

Part sets of two or four drums or an individual drum or octo are common additions to a drum kit.

Complete and half sets of octobans are commonly mounted in clusters of four, in a square pattern. Mounts for four drums in a straight line, dual mounts for two drums, and individual mounts are all also reasonably common. In a drum kit, octobans are most commonly placed to the left of a right-handed drummer, above the hi-hats.