The rototom is a shell-less drum developed by Al Payson and Michael Colgrass that is able to change pitch by rotating its drumhead around a threaded metal ring. Unlike many types of drums, rototoms are designed to have a variable definite pitch leading composers to write specific notes for them as pitched percussion instruments. They are also often used to extend the tom range of a standard drum kit.
Tuning
Rototoms can be tuned quickly by rotating the drumhead, which sits in a threaded metal ring. Rotation raises or lowers the tension hoop relative to the rim, which increases or decreases the pitch of the drum by increasing or decreasing the tension of the drumhead.
Link
Tuning
Rototoms can be tuned quickly by rotating the drumhead, which sits in a threaded metal ring. Rotation raises or lowers the tension hoop relative to the rim, which increases or decreases the pitch of the drum by increasing or decreasing the tension of the drumhead.
Link