A tibia is a sort of organ pipe that is most characteristic of a theatre organ. Tibia pipes are generally made of wood, stopped, from 16' (Occasionally 32') with the top octave pipes (above 1/2', or 6" made of metal, stopped, and pipes from 1/4', 3" made of metal and open. The mouth is cut very high, and the pipes have little harmonic development - the sound approaches that of a

sine wave A sine wave, sinusoidal wave, or just sinusoid is a curve, mathematical curve defined in terms of the ''sine'' trigonometric function, of which it is the graph of a function, graph. It is a type of continuous wave and also a Smoothness, smooth p ...

. There is usually a tremulant on the wind for Tibia pipes - the increase and decrease of wind pressure gives "life" to the sound.

See also