Octoban drums are usually grouped in sets of four or eight. They are different length cylinders or long tubular drums (14 inches to 32 inches long) with the same diameter heads (usually 6 inches). The different lengths of the cylinders or tubes is what gives each drum its distinct tone. Octaban drums can be tuned melodically or to random pitches. Octobans were invented by the Japanease company "Tama" in the mid eighties. Jump to: navigation, search For other kinds of drums, see drum (disambiguation). ... The word cylinder has several meanings. ... Jump to: navigation, search Mid-19th century tool for converting between different standards of the inch An inch is an Imperial and U.S. customary unit of length. ... For the geometric term, see diameter. ...