Wind instrument

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Methods for obtaining different notes

Almost all wind instruments use the last method, often in combination with one of the others, to extend their register.


Wind instruments are typically grouped into two families: [1]

Woodwind instruments were originally made of wood, just as brass instruments were made of brass, but instruments are categorized based on how the sound is produced, not by the material used to construct them. For example Saxophones are typically made of brass, but are woodwind instruments because they produce sound with a vibrating reed. On the other hand, the didgeridoo, the wooden cornett (not to be confused with the cornet), and the serpent are all made of wood (or sometimes plastic), and the olifant is made from ivory, but all of them belong to the family of brass instruments because the vibration is initiated by the player's lips.

In the Hornbostel-Sachs scheme of musical instrument classification, wind instruments are classed as aerophones.

Physics of sound production

Sound production in all wind instruments depends on the entry of air into a flow-control valve attached to a resonant chamber (resonator). The resonator is typically a long cylindrical or conical tube, open at the far end. A pulse of high pressure from the valve will travel down the tube at the speed of sound. It will be reflected from the open end as a return pulse of low pressure. Under suitable conditions, the valve will reflect the pulse back, with increased energy, until a standing wave forms in the tube.

Reed instruments such as the clarinet or oboe have a flexible reed or reeds at the mouthpiece, forming a pressure-controlled valve. An increase in pressure inside the chamber will decrease the pressure differential across the reed; the reed will open more, increasing the flow of air. [2] [3] The increased flow of air will increase the internal pressure further, so a pulse of high pressure arriving at the mouthpiece will reflect as a higher-pressure pulse back down the tube. Standing waves inside the tube will be odd multiples of a quarter-wavelength, [4] with a pressure anti-node at the mouthpiece, and a pressure node at the open end. The reed vibrates at a rate determined by the resonator.

For Lip Reed (brass) instruments, the players control the tension in their lips so that they vibrate under the influence of the air flowing through them. [5] [6] They adjust the vibration so that the lips are most closed, and the air flow is lowest, when a low-pressure pulse arrives at the mouthpiece, to reflect a low-pressure pulse back down the tube. Standing waves inside the tube will be odd multiples of a quarter-wavelength, with a pressure anti-node at the mouthpiece, and a pressure node at the open end.

For Air Reed (flute and fipple-flute) instruments, the thin grazing air sheet (planar jet) flowing across an opening (mouth) in the pipe interacts with a sharp edge (labium) to generate sound. [7] The jet is generated by the player, when blowing through a thin slit (flue). For recorders and flue organ pipes this slit is manufactured by the instrument maker and has a fixed geometry. In a transverse flute or a pan flute the slit is formed by the musicians between their lips.

Due to acoustic oscillation of the pipe the air in the pipe is alternatively compressed and expanded. [8] This results in an alternating flow of air into and out of the pipe through the pipe mouth. The interaction of this transversal acoustic flow with the planar air jet induces at the flue exit (origin of the jet) a localised perturbation of the velocity profile of the jet. This perturbation is strongly amplified by the intrinsic instability of the jet as the fluid travels towards the labium. This results into a global transversal motion of the jet at the labium.

The amplification of perturbations of a jet by its intrinsic instability can be observed when looking at a plume of cigarette smoke. Any small amplitude motion of the hand holding the cigarette results into an oscillation of the plume increasing with distance upwards and eventually a chaotic motion (turbulence). The same jet oscillation can be triggered by gentle air flow in the room, which can be verified by waving with the other hand.

The oscillation of the jet around the labium results into a fluctuating force of the airflow on the labium. Following the third law of Newton the labium exerts an opposite reaction force on the flow. One can demonstrate that this reaction force is the source of sound that drives the acoustic oscillation of the pipe.

A quantitative demonstration of the nature of this type of sound source has been provided by Alan Powell [9] when studying a planar jet interacting with a sharp edge in the absence of pipe (so called edgetone). The sound radiated from the edgetone can be predicted from a measurement of the unsteady force induced by the jet flow on the sharp edge (labium). The sound production by the reaction of the wall to an unsteady force of the flow around an object is also producing the aeolian sound of a cylinder placed normal to an air-flow (singing wire phenomenon). In all these cases (flute, edgetone, aeolian tone...) the sound production does not involve a vibration of the wall. Hence the material in which the flute is made is not relevant for the principle of the sound production. There is no essential difference between a golden or a silver flute. [10]

The sound production in a flute can be described by a lumped element model in which the pipe acts as an acoustic swing (mass-spring system, resonator) that preferentially oscillates at a natural frequency determined by the length of the tube. The instability of the jet acts as an amplifier transferring energy from the steady jet flow at the flue exit to the oscillating flow around the labium. The pipe forms with the jet a feedback loop. These two elements are coupled at the flue exit and at the labium. At the flue exit the transversal acoustic flow of the pipe perturbs the jet. At the labium the jet oscillation results in a generation of acoustic waves, which maintain the pipe oscillation.

The acoustic flow in the pipe can for a steady oscillation be described in terms of standing waves. These waves have a pressure node at the mouth opening and another pressure node at the opposite open pipe termination. Standing waves inside such an open-open tube will be multiples of a half-wavelength. [4]

To a rough approximation, a tube of about 40 cm. will exhibit resonances near the following points:

In practice, however, obtaining a range of musically useful tones from a wind instrument depends to a great extent on careful instrument design and playing technique.

The frequency of the vibrational modes depends on the speed of sound in air, which varies with air density. A change in temperature, and only to a much smaller degree also a change in humidity, influences the air density and thus the speed of sound, and therefore affects the tuning of wind instruments. The effect of thermal expansion of a wind instrument, even of a brass instrument, is negligible compared to the thermal effect on the air.


The bell of a B-flat clarinet Clarinet Bell.JPG
The bell of a B-flat clarinet

The bell of a wind instrument is the round, flared opening opposite the mouthpiece. It is found on clarinets, saxophones, oboes, horns, trumpets and many other kinds of instruments. On brass instruments, the acoustical coupling from the bore to the outside air occurs at the bell for all notes, and the shape of the bell optimizes this coupling. It also plays a major role in transforming the resonances of the instrument. [11] On woodwinds, most notes vent at the uppermost open tone holes; only the lowest notes of each register vent fully or partly at the bell, and the bell's function in this case is to improve the consistency in tone between these notes and the others.

Breath pressure

Playing some wind instruments, in particular those involving high breath pressure resistance, produce increases in intraocular pressure, which has been linked to glaucoma as a potential health risk. One 2011 study focused on brass and woodwind instruments observed "temporary and sometimes dramatic elevations and fluctuations in IOP". [12] Another study found that the magnitude of increase in intraocular pressure correlates with the intraoral resistance associated with the instrument and linked intermittent elevation of intraocular pressure from playing high-resistance wind instruments to incidence of visual field loss. [13] The range of intraoral pressure involved in various classes of ethnic wind instruments, such as Native American flutes, has been shown to be generally lower than Western classical wind instruments. [14]

See also

Related Research Articles

<span class="mw-page-title-main">Brass instrument</span> Class of musical instruments

A brass instrument is a musical instrument that produces sound by sympathetic vibration of air in a tubular resonator in sympathy with the vibration of the player's lips. Brass instruments are also called labrosones or labrophones, from Latin and Greek elements meaning 'lip' and 'sound'.

<span class="mw-page-title-main">Clarinet</span> Single-reed woodwind instrument

The clarinet is a single-reed instrument in the woodwind family, with a nearly cylindrical bore and a flared bell.

<span class="mw-page-title-main">Embouchure</span> Players mouth setup for a wind instrument

Embouchure or lipping is the use of the lips, facial muscles, tongue, and teeth in playing a wind instrument. This includes shaping the lips to the mouthpiece of a woodwind instrument or the mouthpiece of a brass instrument. The word is of French origin and is related to the root bouche, 'mouth'. Proper embouchure allows instrumentalists to play their instrument at its full range with a full, clear tone and without strain or damage to their muscles.

<span class="mw-page-title-main">Woodwind instrument</span> Family of musical wind instruments

Woodwind instruments are a family of musical instruments within the greater category of wind instruments. Common examples include flute, clarinet, oboe, bassoon, and saxophone. There are two main types of woodwind instruments: flutes and reed instruments. The main distinction between these instruments and other wind instruments is the way in which they produce sound. All woodwinds produce sound by splitting the air blown into them on a sharp edge, such as a reed or a fipple. Despite the name, a woodwind may be made of any material, not just wood. Common examples include brass, silver, cane, as well as other metals such as gold and platinum. The saxophone, for example, though made of brass, is considered a woodwind because it requires a reed to produce sound. Occasionally, woodwinds are made of earthen materials, especially ocarinas.

<span class="mw-page-title-main">Reed (mouthpiece)</span> Sound producing part of some musical instruments

A reed is a thin strip of material that vibrates to produce a sound on a musical instrument. Most woodwind instrument reeds are made from Arundo donax or synthetic material. Tuned reeds are made of metal or synthetics. Musical instruments are classified according to the type and number of reeds.

Hornbostel–Sachs or Sachs–Hornbostel is a system of musical instrument classification devised by Erich Moritz von Hornbostel and Curt Sachs, and first published in the Zeitschrift für Ethnologie in 1914. An English translation was published in the Galpin Society Journal in 1961. It is the most widely used system for classifying musical instruments by ethnomusicologists and organologists. The system was updated in 2011 as part of the work of the Musical Instrument Museums Online (MIMO) Project.

<span class="mw-page-title-main">Aerophone</span> Musical instruments that are played by vibration of air

An aerophone is a musical instrument that produces sound primarily by causing a body of air to vibrate, without the use of strings or membranes, and without the vibration of the instrument itself adding considerably to the sound.

Overblowing is the manipulation of supplied air through a wind instrument that causes the sounded pitch to jump to a higher one without a fingering change or the operation of a slide. Overblowing may involve a change in the air pressure, in the point at which the air is directed, or in the resonance characteristics of the chamber formed by the mouth and throat of the player.

<span class="mw-page-title-main">Fipple</span> Musical instrument

The term fipple specifies a variety of end-blown flute that includes the flageolet, recorder, and tin whistle. The Hornbostel–Sachs system for classifying musical instruments places this group under the heading "Flutes with duct or duct flutes." The label "fipple flute" is frequently applied to members of the subgroup but there is no general agreement about the structural detail of the sound-producing mechanism that constitutes the fipple, itself.

A multiphonic is an extended technique on a monophonic musical instrument in which several notes are produced at once. This includes wind, reed, and brass instruments, as well as the human voice. Multiphonic-like sounds on string instruments, both bowed and hammered, have also been called multiphonics, for lack of better terminology and scarcity of research.

<span class="mw-page-title-main">Flue pipe</span>

A flue pipe is an organ pipe that produces sound through the vibration of air molecules, in the same manner as a recorder or a whistle. Air under pressure is driven through a flue and against a sharp lip called a labium, causing the column of air in the pipe to resonate at a frequency determined by the pipe length. Thus, there are no moving parts in a flue pipe. This is in contrast to reed pipes, whose sound is driven by beating reeds, as in a clarinet. Flue pipes are common components of pipe organs.

<span class="mw-page-title-main">Organ pipe</span> Musical instrument part

An organ pipe is a sound-producing element of the pipe organ that resonates at a specific pitch when pressurized air is driven through it. Each pipe is tuned to a specific note of the musical scale. A set of organ pipes of similar timbre comprising the complete scale is known as a rank; one or more ranks constitutes a stop.

<span class="mw-page-title-main">Helmholtz resonance</span> Phenomenon of air resonance in a cavity

Helmholtz resonance or wind throb is the phenomenon of air resonance in a cavity, such as when one blows across the top of an empty bottle. The name comes from a device created in the 1850s by Hermann von Helmholtz, the Helmholtz resonator, which he used to identify the various frequencies or musical pitches present in music and other complex sounds.

<span class="mw-page-title-main">Single-reed instrument</span> Class of woodwind instruments

A single-reed instrument is a woodwind instrument that uses only one reed to produce sound. The very earliest single-reed instruments were documented in ancient Egypt, as well as the Middle East, Greece, and the Roman Empire. The earliest types of single-reed instruments used idioglottal reeds, where the vibrating reed is a tongue cut and shaped on the tube of cane. Much later, single-reed instruments started using heteroglottal reeds, where a reed is cut and separated from the tube of cane and attached to a mouthpiece of some sort. By contrast, in a double reed instrument, there is no mouthpiece; the two parts of the reed vibrate against one another. Reeds are traditionally made of cane and produce sound when air is blown across or through them. The type of instruments that use a single reed are clarinets and saxophone. The timbre of a single and double reed instrument is related to the harmonic series caused by the shape of the corpus. E.g. the clarinet is only including the odd harmonics due to air column modes canceling out the even harmonics. This may be compared to the timbre of a square wave.

<span class="mw-page-title-main">Acoustic resonance</span> Resonance phenomena in sound and musical devices

Acoustic resonance is a phenomenon in which an acoustic system amplifies sound waves whose frequency matches one of its own natural frequencies of vibration.

<span class="mw-page-title-main">Reed pipe</span> Type of organ pipe

A reed pipe is an organ pipe that is sounded by a vibrating brass strip known as a reed. Air under pressure is directed towards the reed, which vibrates at a specific pitch. This is in contrast to flue pipes, which contain no moving parts and produce sound solely through the vibration of air molecules. Reed pipes are common components of pipe organs.

<span class="mw-page-title-main">Bore (wind instruments)</span>

In music, the bore of a wind instrument is its interior chamber. This defines a flow path through which air travels, which is set into vibration to produce sounds. The shape of the bore has a strong influence on the instrument's timbre.

<span class="mw-page-title-main">Mouthpiece (woodwind)</span>

The mouthpiece of a woodwind instrument is that part of the instrument which is placed partly in the player's mouth. Single-reed instruments, capped double-reed instruments, and fipple flutes have mouthpieces while exposed double-reed instruments and open flutes do not. The characteristics of a mouthpiece and reed can play a significant role on the sound of the instrument.

<span class="mw-page-title-main">Hydraulophone</span> Hydraulic musical instrument

A hydraulophone is a tonal acoustic musical instrument played by direct physical contact with water where sound is generated or affected hydraulically. The hydraulophone was described and named by Steve Mann in 2005, and patented in 2011. Typically, sound is produced by the same hydraulic fluid in contact with the player's fingers. It has been used as a sensory exploration device for low-vision individuals.


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  11. "Producing a harmonic sequence of notes with a trumpet".
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  14. Clinton F. Goss (August 2013). "Intraoral Pressure in Ethnic Wind Instruments". Intraoral Pressure in Ethnic Wind Instruments (PDF). Flutopedia. arXiv: 1308.5214 . Bibcode:2013arXiv1308.5214G . Retrieved 22 Aug 2013. alternate url

Further reading

Wind Instrument Summary CDs are: "Microsoft Musical Instruments" ( now out of production but sometimes available on Amazon ), and "Tuneful Tubes?" ( )