Bore (wind instruments)
The bore of a wind instrument is its interior chamber that defines a flow path through which air travels and is set into vibration to produce sounds. The shape of the bore has a strong influence on the instrument's timbre.
Bore shapes
The cone and the cylinder are the two idealized shapes used to describe the bores of wind instruments. These shapes affect the harmonics associated with the timbre of the instrument. The conical bore has a timbre composed of odd and even harmonics, while the closed cylindrical bore or closed tube is composed primarily of odd harmonics.
The harmonic characteristics of instruments such as the clarinet (closed cylinder) are more variable than a given waveform and bore alone is not the only determining factor. The timbre of a clarinet, for instance, mainly depends on the construction of the mouthpiece and the properties of the reed. Furthermore, minute changes in air pressure and pressure applied to the reed (vibrato, slurs) modulate the tone.
