A tibia is a sort of
organ pipe
An organ pipe is a sound-producing element of the pipe organ that resonator, resonates at a specific Pitch (music), pitch when pressurized air (commonly referred to as ''wind'') is driven through it. Each pipe is tuned to a note of the musical ...
that is most characteristic of a
theatre organ
A theatre organ (also known as a theater organ, or, especially in the United Kingdom, a cinema organ) is a type of pipe organ developed to accompany silent films from the 1900s to the 1920s.
Theatre organs have horseshoe-shaped arrangements of ...
.
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 sinusoid (symbol: ∿) is a periodic function, periodic wave whose waveform (shape) is the trigonometric function, trigonometric sine, sine function. In mechanics, as a linear motion over time, this is ''simple ...
.
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
Encyclopedia of Organ Stops
Aerophones
Pipe organ components
{{FreeReed-instrument-stub