Flute
The flute is a musical instrument of the woodwind family. Unlike other woodwind instruments, a flute is a reedless wind instrument that produces its sound from the flow of air against an edge. A musician who plays the flute can be referred to as a flute player, a flautist, or a flutist. A flute produces sound when a stream of air directed across a hole in the instrument creates a vibration of air at the hole.
The air stream across this hole creates a Bernoulli, or siphon, effect leading to a von Karman vortex street. This excites the air contained in the usually cylindrical resonant cavity within the flute. The player changes the pitch of the sound produced by opening and closing holes in the body of the instrument, thus changing the effective length of the resonator and its corresponding resonant frequency. By varying the air pressure, a flute player can also change the pitch of a note by causing the air in the flute to resonate at a harmonic other than the fundamental frequency without opening or closing any holes.
To be louder, a flute must use a larger resonator, a larger air stream, or increased air stream velocity. A flute's volume can generally be increased by making its resonator and tone holes larger. This is why a police whistle, a form of flute, is very wide for its pitch, and why a pipe organ can be far louder than a concert flute: a large organ pipe can contain several cubic feet of air, and its tone hole may be several inches wide, while a concert flute's air stream measures a fraction of an inch across.
The air stream must be directed at the correct angle and velocity, or else the air in the flute will not vibrate. In fippled or ducted flutes, a precisely formed and placed windway will compress and channel the air to the labium ramp edge across the open window.
Generally, the quality called timbre or "tone colour" varies because the flute can produce harmonics in different proportions or intensities. The tone color can be modified by changing the internal shape of the bore, such as the conical taper, or the diameter-to-length ratio. A harmonic is a frequency that is a whole number multiple of a lower register, or "fundamental" note of the flute. Generally the air stream is thinner (vibrating in more modes), faster (providing more energy to excite the air's resonance), and aimed across the hole less deeply (permitting a more shallow deflection of the air stream) in the production of higher harmonics or upper partials.
Head joint geometry appears particularly critical to acoustic performance and tone, but there is no clear consensus on a particular shape amongst manufacturers. In its most basic form, a flute can be an open tube which is blown like a bottle. There are several broad classes of flutes. With most flutes, the musician blows directly across the edge of the mouthpiece. However, some flutes, such as the whistle, gemshorn, flageolet, recorder, tin whistle, tonette, fujara, and ocarina have a duct that directs the air onto the edge. These are known as fipple flutes. The fipple gives the instrument a distinct timbre which is different from non-fipple flutes and makes the instrument easier to play, but takes a degree of control away from the musician.
Another division is between side-blown (or transverse) flutes, such as the Western concert flute, piccolo, fife, dizi, and bansuri; and end-blown flutes, such as the ney, xiao, kaval, danso, shakuhachi, Anasazi flute, and quena. End-blown flutes should not be confused with fipple flutes such as the recorder, which are also played vertically but have an internal duct to direct the air flow across the edge of the tone hole.
Flutes may be open at one or both ends. The ocarina, pan pipes, police whistle, and bosun's whistle are closed-ended. Open-ended flutes such as the concert flute and the recorder have more harmonics, and thus more flexibility for the player, and brighter timbres. An organ pipe may be either open or closed, depending on the sound desired.
The bamboo flute is an important instrument in Indian classical music, and developed independently of the Western flute. The Hindu god Krishna is traditionally considered a master of the Bansuri. The Indian flutes are very simple compared to the Western counterparts; they are made of bamboo and are keyless.
The sring, is a relatively small, end-blown flute with a nasal tone quality and the pitch of a piccolo. It is made of wood or cane, usually with seven finger holes and one thumb hole, producing a diatonic scale. The sring is used by shepherds to play various signals and tunes connected with their work, and also lyrical love songs called chaban bayaty, as well as programmatic pieces. The sring is also used in combination with the def and the dohl to provide music for dancing