Editing Clarinet (section)

==Acoustics==
The clarinet's [[cylinder (geometry)|cylindrical]] bore is the main reason for its distinctive [[timbre]], which varies between the three main [[register (music)|registers]] (the ''chalumeau'', ''clarion'', and ''altissimo''). The A and B{{music|flat}} clarinets have nearly the same bore and nearly identical tonal quality, although the A typically has a slightly warmer sound.{{Sfn|Pino|1998|pp=26–28}} The tone of the [[E-flat clarinet|E{{music|flat}} clarinet]] is brighter and can be heard through loud orchestral textures.{{sfn|Black|Gerou|2005|p=66}} The [[bass clarinet]] has a characteristically deep, mellow sound, and the [[alto clarinet]] sounds similar to the bass, though not as dark.{{sfn|Black|Gerou|2005|p=50}}
[[File:Sound wave propagation in the soprano clarinet.jpg|thumb|Sound wave propagation in the soprano clarinet]]

The production of sound by a clarinet follows these steps:<ref name="physics">{{cite web|url=http://www.phys.unsw.edu.au/jw/clarinetacoustics.html |title=Acoustics of the clarinet|accessdate=27 August 2021|archive-url=https://web.archive.org/web/20110219095950/http://www.phys.unsw.edu.au/~jw/clarinetacoustics.html#pipe |archive-date=19 February 2011 |publisher= University of New South Wales}}</ref><ref name=pipes>{{cite web|url=http://www.phys.unsw.edu.au/jw/flutes.v.clarinets.html|title=Open vs closed pipes (flutes vs clarinets)|publisher=University of New South Wales|accessdate=24 October 2022}}</ref>{{sfn|Page et al.|2015}}

# The mouthpiece and reed are surrounded by the player's lips, which put light, even pressure on the reed and form an airtight seal.{{sfn|Harris|1995b}} Air is blown past the reed and down the instrument. In the same way a flag flaps in the breeze, the air rushing past the reed causes it to vibrate. As air pressure from the mouth increases, the amount the reed vibrates increases until the reed hits the mouthpiece.<br />The reed stays pressed against the mouthpiece until either the springiness of the reed forces it to open or a returning pressure wave 'bumps' into the reed and opens it. Each time the reed opens, a puff of air goes through the gap, after which the reed swings shut again. When played loudly, the reed can spend up to 50% of the time shut.<ref>{{cite journal |last1=Backus |first1=J |year=1961 |title=Vibrations of the reed and the air column in the clarinet |journal=The Journal of the Acoustical Society of America |volume=33 |issue=6 |pages=806–809 |doi=10.1121/1.1908803}}</ref> The 'puff of air' or [[compression wave]] (at around 3% greater pressure than the surrounding air<ref name="physics"/>) travels down the cylindrical tube and escapes at the point where the tube opens out. This is either at the closest open hole or at the end of the tube (see diagram: image 1).
# More than a 'neutral' amount of air escapes from the instrument, which creates a slight vacuum or [[rarefaction]] in the clarinet tube. This rarefaction wave travels back up the tube (image 2).
# The rarefaction is reflected off the sloping end wall of the clarinet mouthpiece. The opening between the reed and the mouthpiece makes very little difference to the reflection of the rarefaction wave. This is because the opening is very small compared to the size of the tube, so almost the entire wave is reflected back down the tube even if the reed is completely open at the time the wave hits (image 3).
# When the rarefaction wave reaches the other (open) end of the tube, air rushes in to fill the slight vacuum. A little more than a 'neutral' amount of air enters the tube and causes a compression wave to travel back up the tube (image 4). Once the compression wave reaches the mouthpiece end of the 'tube', it is reflected again back down the pipe. However at this point, either because the compression wave 'bumped' the reed or because of the natural vibration cycle of the reed, the gap opens and another 'puff' of air is sent down the pipe.
# The original compression wave, now greatly reinforced by the second 'puff' of air, sets off on another two trips down the pipe (travelling four pipe lengths in total) before the cycle is repeated again.<ref name=physics/>

In addition to this primary compression wave, other waves, known as [[harmonics]], are created. Harmonics are caused by factors including the imperfect wobbling and shaking of the reed, the reed sealing the mouthpiece opening for part of the wave cycle (which creates a flattened section of the sound wave), and imperfections (bumps and holes) in the bore. A wide variety of compression waves are created, but only some (primarily the odd harmonics) are reinforced.<ref>{{cite journal |last1=Barthet |first1=M. |last2=Guillemain |first2=P. |last3=Kronland-Martinet |first3=R. |last4=Ystad |first4=S. |year=2010 |title=From clarinet control to timbre perception |journal=Acta Acustica United with Acustica |volume=96 |issue=4 |pages=678–689 |doi=10.3813/AAA.918322}}</ref>{{sfn|Page et al.|2015}} This in combination with the cut-off frequency (where a significant drop in resonance occurs) results in the characteristic tone of the clarinet.{{sfn|Page et al.|2015}}

The [[Bore (wind instruments)|bore]] is [[Cylinder|cylindrical]] for most of the tube with an inner bore diameter between {{convert|0.575|and|0.585|in|mm}}, but there is a subtle [[hourglass]] shape, with the thinnest part below the junction between the upper and lower joint.{{sfn|Pino|1998|p=24}} This hourglass shape, although invisible to the naked eye, helps to correct the pitch and responsiveness of the instrument.{{sfn|Pino|1998|p=24}} The diameter of the bore affects the instrument's sound characteristics.{{sfn|Page et al.|2015}} The bell at the bottom of the clarinet flares out to improve the tone and tuning of the lowest notes.<ref name="physics"/> Modern standard clarinets are [[musical tuning|tuned]] to 440 to 442 [[hertz|Hz]]&mdash;[[concert pitch]] is 440&nbsp;Hz&mdash;but adjusting the length of the bore can alter tuning, for example to match the pitch of a larger ensemble. Other factors that impact tuning include temperature and [[dynamics (music)|dynamics]].{{sfn|Ellsworth|2015|p=31}}{{sfn|Coppenbarger|2015|p=36}}{{sfn|Pino|1998|p=116}}

Most modern clarinets have "undercut" [[tone hole]]s that improve intonation and sound. Undercutting means [[chamfer]]ing the bottom edge of tone holes inside the bore. Acoustically, this makes the tone hole function as if it were larger, but its main function is to allow the air column to follow the curve up through the tone hole (surface tension) instead of "blowing past" it under the increasingly directional frequencies of the upper registers.<ref>{{cite journal |last1=Gibson |first1=Lee |year=1968 |title=Fundamentals of acoustical design of the soprano clarinet |doi=10.2307/3391282 |journal=Music Educators Journal |volume=54 |issue=6 |pages=113–115 |jstor=3391282 }}</ref> Covering or uncovering the tone holes varies the length of the pipe, changing the [[acoustic resonance|resonant frequencies]] of the enclosed air column and hence the [[Pitch (music)|pitch]]. The player moves between the chalumeau and clarion registers through use of the [[register key]]. The open register key stops the fundamental frequency from being reinforced, making the reed vibrate at three times the frequency, which produces a note a twelfth above the original note.<ref name="physics" />

The fixed reed and fairly uniform diameter of the clarinet result in an acoustical performance approximating that of a cylindrical [[stopped pipe]].<ref name="physics"/> [[Recorder (musical instrument)|Recorders]] use a tapered internal bore to [[Overblowing|overblow]] at the [[octave]] when the thumb/register hole is pinched open, while the clarinet, with its cylindrical bore, overblows at the [[Twelfth (interval)|twelfth]].<ref name="physics"/>  The low chalumeau register plays fundamentals, but the clarion (second) register plays the third harmonics, a perfect twelfth higher than the fundamentals.<ref name="physics" /><ref name=pipes/> The first several notes of the altissimo (third) range, aided by the register key and venting with the first left-hand hole, play the fifth harmonics, a perfect twelfth plus a major sixth above the fundamentals.<ref name=physics/>{{sfn|Page et al.|2015}} The fifth and seventh harmonics are also available, sounding a further [[Interval (music)|sixth]] and [[Fourth (interval)|fourth]] (a flat, diminished fifth) higher respectively; these are the notes of the altissimo register.<ref name="physics" />

The lip position and pressure, shaping of the vocal tract, choice of reed and mouthpiece, amount of air pressure created, and evenness of the airflow account for most of the player's ability to control the tone of a clarinet.<ref>{{cite conference|last1=Almeida|first1= A|last2= Lemare|first2= J|last3= Sheahan|first3= M|last4=Judge|first4= J|last5= Auvray|first5= R|last6= Dang|first6= K|last7=Wolfe|first7= J|year=2010|url=http://newt.phys.unsw.edu.au/jw/reprints/clarinetcartography.pdf |archive-url=https://web.archive.org/web/20110303163646/http://newt.phys.unsw.edu.au/jw/reprints/clarinetcartography.pdf |archivedate=3 March 2011 |url-status=live |title=Clarinet parameter cartography: automatic mapping of the sound produced as a function of blowing pressure and reed force|conference=International Symposium on Music Acoustics}}</ref> Their vocal tract will be shaped to resonate at frequencies associated with the tone being produced.<ref>{{cite journal |last1=Pàmies-Vilà |first1=Montserrat |last2=Hofmann |first2=Alex |last3=Chatziioannou |first3=Vasileios |year=2020 |title=The influence of the vocal tract on the attack transients in clarinet playing |journal=[[Journal of New Music Research]] |volume=49 |issue=2 |pages=126–135 |doi=10.1080/09298215.2019.1708412|pmid=32256677 |pmc=7077444 }}</ref>

[[Vibrato]], a pulsating change of pitch, is rare in classical literature; however, certain performers, such as [[Richard Stoltzman]], use vibrato in classical music.<ref>{{cite news|newspaper=The New York Times|date=16 August 1992|last=Blum|first=David|title=Teaching the clarinet to speak with his voice|url=https://www.nytimes.com/1992/08/16/arts/classical-music-teaching-the-clarinet-to-speak-with-his-voice.html}}</ref> Other effects are [[glissando]], [[growling]], trumpet sounds, double tongue, [[flutter tongue]] and [[circular breathing]]. Special lip-bending may be used to play [[Microtonal music|microtonal]] intervals.{{sfn|Heaton|1995}} There have also been efforts to create a [[quarter tone clarinet]].<ref name="jl">{{cite web |last=Zakian |first=Lee |title=The clarinet history |url=http://www.jlpublishing.com/ClarinetHistory.htm |publisher=JL Publishing |accessdate=2 July 2009 |archive-date=14 April 2016 |archive-url=https://web.archive.org/web/20160414122314/http://www.jlpublishing.com/ClarinetHistory.htm |url-status=live }}</ref><ref>{{cite web |last=Richards |first=E. Michael |work=The Clarinet of the Twenty-First Century |url=http://userpages.umbc.edu/~emrich/chapter2-5.html |title= Single sounds |accessdate=9 October 2012 |archive-date=11 December 2012 |archiveurl=https://archive.today/20121211103401/http://userpages.umbc.edu/~emrich/chapter2-5.html |url-status=live }}</ref>