In
music
Music is generally defined as the art of arranging sound to create some combination of form, harmony, melody, rhythm or otherwise expressive content. Exact definitions of music vary considerably around the world, though it is an aspe ...
, the bore of a
wind instrument
A wind instrument is a musical instrument that contains some type of resonator (usually a tube) in which a column of air is set into vibration by the player blowing into (or over) a mouthpiece set at or near the end of the resonator. The pitc ...
(including
woodwind
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 re ...
and
brass
Brass is an alloy of copper (Cu) and zinc (Zn), in proportions which can be varied to achieve different mechanical, electrical, and chemical properties. It is a substitutional alloy: atoms of the two constituents may replace each other wi ...
) is its interior chamber. This defines a flow path through which air travels, which is set into
vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic, such as the motion of a pendulum—or random, su ...
to produce sounds. The shape of the bore has a strong influence on the instrument's
timbre.
Bore shapes
The
cone and the
cylinder
A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base.
A cylinder may also be defined as an ...
are the two idealized shapes used to describe the bores of
wind instrument
A wind instrument is a musical instrument that contains some type of resonator (usually a tube) in which a column of air is set into vibration by the player blowing into (or over) a mouthpiece set at or near the end of the resonator. The pitc ...
s. Other shapes are not generally used, as they tend to produce
dissonant, anharmonic overtones and an unmusical sound. Instruments may consist of a primarily conical or cylindrical tube, but begin in a mouthpiecs, and end in a rapidly-expanding "flare" or "
bell". This flare reduces the
acoustic impedance mismatch between the instrument and the air, allowing the instrument to transmit sound to the air more effectively.
These shapes affect the prominence of
harmonics associated with the timbre of the instrument. A bore that flares from the mouthpiece reduces
resistance to the breath, while a bore that narrows from the mouth increases it, compared to a cylinder.
Cylindrical bore
The diameter of a cylindrical bore remains constant along its length. The acoustic behavior depends on whether the instrument is ''stopped'' (closed at one end and open at the other), or ''open'' (at both ends). For an open pipe, the wavelength produced by the first
normal mode
A normal mode of a dynamical system is a pattern of motion in which all parts of the system move sinusoidally with the same frequency and with a fixed phase relation. The free motion described by the normal modes takes place at fixed frequencies. ...
(the
fundamental note) is approximately twice the length of the pipe. The wavelength produced by the second normal mode is half that, that is, the length of the pipe, so its pitch is an
octave
In music, an octave ( la, octavus: eighth) or perfect octave (sometimes called the diapason) is the interval between one musical pitch and another with double its frequency. The octave relationship is a natural phenomenon that has been refer ...
higher; thus an open cylindrical bore instrument
overblows at the octave. This corresponds to the second harmonic, and generally the harmonic spectrum of an open cylindrical bore instrument is strong in both even and odd harmonics. For a stopped pipe, the wavelength produced by the first normal mode is approximately four times the length of the pipe. The wavelength produced by the second normal mode is one third that, i.e. the 4/3 length of the pipe, so its pitch is a twelfth higher; a stopped cylindrical bore instrument overblows at the twelfth. This corresponds to the third harmonic; generally the harmonic spectrum of a stopped cylindrical bore instrument, particularly in its bottom register, is strong in the odd harmonics only. Modern brass instruments however generally make use of the full length of the instrument for every pitch, and are therefore significantly affected by the effects of the mouthpiece and
bell. These modify the instrument's resonances to closely resemble that of a conical pipe, even if the bore is mostly cylindrical.
Instruments having a cylindrical, or mostly cylindrical, bore include:
*
Chalumeau
*
Clarinet
The clarinet is a musical instrument in the woodwind family. The instrument has a nearly cylindrical bore and a flared bell, and uses a single reed to produce sound.
Clarinets comprise a family of instruments of differing sizes and pitch ...
*
Cornamuse
*
Crumhorn
*
Flute
The flute is a family of classical music instrument in the woodwind group. Like all woodwinds, flutes are aerophones, meaning they make sound by vibrating a column of air. However, unlike woodwind instruments with reeds, a flute is a reedles ...
(
Boehm system — open)
*
Recorder
Recorder or The Recorder may refer to:
Newspapers
* ''Indianapolis Recorder'', a weekly newspaper
* ''The Recorder'' (Massachusetts newspaper), a daily newspaper published in Greenfield, Massachusetts, US
* ''The Recorder'' (Port Pirie), a news ...
(renaissance and some modern recorders)
*
Kortholt
*
Rackett (renaissance)
*
Trumpet
The trumpet is a brass instrument commonly used in classical and jazz ensembles. The trumpet group ranges from the piccolo trumpet—with the highest register in the brass family—to the bass trumpet, pitched one octave below the standard ...
*
Trombone
The trombone (german: Posaune, Italian, French: ''trombone'') is a musical instrument in the brass family. As with all brass instruments, sound is produced when the player's vibrating lips cause the air column inside the instrument to vibrate ...
Conical bore
The diameter of a conical bore varies linearly with distance from the end of the instrument. A complete conical bore would begin at zero diameter—the cone's vertex. However, actual instrument bores approximate a
frustum of a cone. The wavelength produced by the first normal mode is approximately twice the length of the cone measured from the vertex. The wavelength produced by the second normal mode is approximately equal to the length of the cone, so its pitch is an octave higher. Therefore, a conical bore instrument, like one with an open cylindrical bore, overblows at the octave and generally has a harmonic spectrum strong in both even and odd harmonics.
Instruments having a conical, or approximately conical, bore include:
*
Alphorn
*
Bassoon
The bassoon is a woodwind instrument in the double reed family, which plays in the tenor and bass ranges. It is composed of six pieces, and is usually made of wood. It is known for its distinctive tone color, wide range, versatility, and virtuos ...
*
Conch shell
*
Cornet
The cornet (, ) is a brass instrument similar to the trumpet but distinguished from it by its conical bore, more compact shape, and mellower tone quality. The most common cornet is a transposing instrument in B, though there is also a so ...
*
Dulcian
*
Euphonium
*
Flugelhorn
The flugelhorn (), also spelled fluegelhorn, flugel horn, or flügelhorn, is a brass instrument that resembles the trumpet and cornet but has a wider, more conical bore. Like trumpets and cornets, most flugelhorns are pitched in B, though som ...
*
Flute
The flute is a family of classical music instrument in the woodwind group. Like all woodwinds, flutes are aerophones, meaning they make sound by vibrating a column of air. However, unlike woodwind instruments with reeds, a flute is a reedles ...
(pre-Boehm)
*
French Horn
The French horn (since the 1930s known simply as the horn in professional music circles) is a brass instrument made of tubing wrapped into a coil with a flared bell. The double horn in F/B (technically a variety of German horn) is the horn most ...
*
Recorder
Recorder or The Recorder may refer to:
Newspapers
* ''Indianapolis Recorder'', a weekly newspaper
* ''The Recorder'' (Massachusetts newspaper), a daily newspaper published in Greenfield, Massachusetts, US
* ''The Recorder'' (Port Pirie), a news ...
(baroque and most contemporary recorders)
*
Oboe
The oboe ( ) is a type of double reed woodwind instrument. Oboes are usually made of wood, but may also be made of synthetic materials, such as plastic, resin, or hybrid composites. The most common oboe plays in the treble or soprano range.
...
*
Rackett (baroque)
*
Rauschpfeife
*
Saxhorn
*
Saxophone
The saxophone (often referred to colloquially as the sax) is a type of Single-reed instrument, single-reed woodwind instrument with a conical body, usually made of brass. As with all single-reed instruments, sound is produced when a reed (mouthpi ...
*
Shawm
*
Tuba
*
Uilleann pipes
Woodwinds
Sections of the bores of
woodwind instrument
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 r ...
s deviate from a true cone or a cylinder. For example, although
oboe
The oboe ( ) is a type of double reed woodwind instrument. Oboes are usually made of wood, but may also be made of synthetic materials, such as plastic, resin, or hybrid composites. The most common oboe plays in the treble or soprano range.
...
s and
oboes d'amore
The oboe d'amore (; Italian for "oboe of love"), less commonly , is a double reed woodwind musical instrument in the oboe family. Slightly larger than the oboe, it has a less assertive and a more tranquil and serene tone, and is considered the ...
are similarly pitched, they have differently shaped terminal bells. Accordingly, the voice of the oboe is described as "piercing" as compared to the more "full" voice of the oboe d'amore.
Although the bore shape of woodwind instruments generally determines their timbre, the instruments' exterior geometry typically has little effect on their voice. In addition, the exterior shape of woodwind instruments may not overtly match the shape of their bores. For example, while oboes and clarinets may outwardly appear similar, oboes have a
conical
A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex.
A cone is formed by a set of line segments, half-lines, or lines c ...
bore while clarinets have a cylindrical bore.
The bore of a
baroque
The Baroque (, ; ) is a style of architecture, music, dance, painting, sculpture, poetry, and other arts that flourished in Europe from the early 17th century until the 1750s. In the territories of the Spanish and Portuguese empires including ...
recorder
Recorder or The Recorder may refer to:
Newspapers
* ''Indianapolis Recorder'', a weekly newspaper
* ''The Recorder'' (Massachusetts newspaper), a daily newspaper published in Greenfield, Massachusetts, US
* ''The Recorder'' (Port Pirie), a news ...
has a "reversed" taper, being wider at the head and narrower at the foot of the instrument.
Most contemporary recorders also have such a conical bore as they are made very similar to baroque recorders. However, multiple
renaissance
The Renaissance ( , ) , from , with the same meanings. is a period in European history marking the transition from the Middle Ages to modernity and covering the 15th and 16th centuries, characterized by an effort to revive and surpass ide ...
,
medieval
In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
and also modern recorders have a
cylindrical bore. Some
tin flageolets also have a reverse taper.
Brasses
Brass instruments also are sometimes categorized as conical or cylindrical, though most in fact have cylindrical sections between a conical section (the
mouthpiece taper or
leadpipe) and a non-conical, non-cylindrical flaring section (the bell). Benade gives the following typical proportions:
These proportions vary as valves or slides are operated; the above numbers are for instruments with the valves open or the slide fully in. This deviation from standard models of cylindrical and conical tubes means normal mode frequencies of brass instruments do not correspond to integer multiples of the first mode, which is not used for playing. The higher modes however do correspond fairly to integer multiples of a "fictitious fundamental" which can often still be played as a
pedal tone.
Players of brasses (in contrast to woodwinds) are able to "lip" notes up or down substantially, and on some instruments make use of privileged frequencies (pedal tones and
false tones), to obtain in-tune notes outside of the range allowed for by the normal modes.
See also
*
Acoustic resonance
Acoustic resonance is a phenomenon in which an acoustic system amplifies sound waves whose frequency matches one of its own natural frequencies of vibration (its ''resonance frequencies'').
The term "acoustic resonance" is sometimes used to nar ...
*
Harmonic series (music)
A harmonic series (also overtone series) is the sequence of harmonics, musical tones, or pure tones whose frequency is an integer multiple of a ''fundamental frequency''.
Pitched musical instruments are often based on an acoustic resonator ...
*
Square wave
*
Triangle wave
A triangular wave or triangle wave is a non-sinusoidal waveform named for its triangular shape. It is a periodic, piecewise linear, continuous real function.
Like a square wave, the triangle wave contains only odd harmonics. However, ...
Sources
Further reading
* Nederveen, Cornelis Johannes, ''Acoustical aspects of woodwind instruments''. Amsterdam, Frits Knuf, 1969.
* for waveform and harmonic characteristics
clarinet and a conical, cylindrica
Bryan H. Suits, ''Phy.MTU.edu''.
** The previous author refers to: "The conical bore in musical acoustics," by R. D. Ayers, L. J. Eliason, and D. Mahgerefteh, ''American Journal of Physics'', Vol 53, No. 6, pgs 528-537, (1985).
* A short description with waveforms of th
Also
of acoustics (with calculations and waveforms) in wind instruments Jan. 18, 2011. ''GSU.edu''.
{{Reed aerophones
Sound
Acoustics
Aerophones