Choroi Tubular Bells. Choroi Tubular Bells are chimes of copper pipes which create a vibrant bell-like tone. The sound is reinforced by the curved ash wood frame, the V-shaped resonance box, and the hammered surface of the bell pipes. Different mallets can be used to produce different timbres. Achieving a clear, bell-like sound requires a hard mallet. Tubular Bells spread interval scale. Ash wood resonance frame, length: 40 cm, height: 55 cm (length: 15.75 inch, height: 21.65 inch), 7 copper pipes, scale: d''-g''-a''-d'''-e'''-a'''-b'''.