The Cylindrum is a massive tuned percussion instrument designed using the principle of open and closed air column resonance. The instrument was constructed by Gregg Stephens with the help some rather involved mathematics, plenty of elbow grease and quite a few bloody fingers. The end result is a massive 20-foot-long tuned percussion instrument with a pitch range spanning a full 4 octaves. Overall, it sounds like a strange organic synthesizer coupled with tuned tom toms. With deeply nuanced dynamic velocity layering and extensive round-robin variation, this instrument is truly an experimental percussionist's dream come true.