Editing Flute (section)

==Acoustics==

A flute produces sound when a stream of air directed across a hole in the instrument creates a vibration of air at the hole.<ref>[http://www.phys.unsw.edu.au/jw/fluteacoustics.html#airjet Flute acoustics] {{Webarchive|url=https://web.archive.org/web/20100813223531/http://www.phys.unsw.edu.au/jw/fluteacoustics.html#airjet |date=13 August 2010 }}, UNSW. Retrieved June 2007.</ref><ref>{{cite web| author=Wolfe, Joe | title=Introduction to flute acoustics | work=UNSW Music Acoustics | url=http://www.phys.unsw.edu.au/music/flute/ | access-date=18 January 2006 }}</ref> The airstream creates a [[Bernoulli effect|Bernoulli]] or siphon. This excites the air contained in the [[resonant cavity]] (usually cylindrical) within the flute. The flutist changes the [[pitch (music)|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 flutist can also change the pitch by causing the air in the flute to resonate at a [[harmonic]] rather than the [[fundamental frequency]] without opening or closing any of the holes.<ref>{{cite web | url=http://hyperphysics.phy-astr.gsu.edu/hbase/music/flute.html#c4 | title=The Flute | website=HyperPhysics | access-date=20 March 2016}}</ref>

Head joint geometry appears particularly critical to acoustic performance and tone,<ref>{{Cite journal | last = Spell | first = Eldred | title = Anatomy of a Headjoint | journal = The Flute Worker | year = 1983 | url = http://eldredspellflutes.com/Articles.htm | issn = 0737-8459 | url-status = dead | archive-url = https://web.archive.org/web/20071116141712/http://eldredspellflutes.com/Articles.htm | archive-date = 16 November 2007 }}</ref> but there is no clear consensus among manufacturers on a particular shape. Acoustic impedance of the embouchure hole appears the most critical parameter.<ref>{{cite web| last = Wolfe | first = Joe | title = Acoustic impedance of the flute | work = Flute acoustics: an introduction | url = http://www.phys.unsw.edu.au/~jw/fluteacoustics.html#acousticimpedance}}</ref> Critical variables affecting this acoustic impedance include: the length of the chimney (the hole between the lip-plate and the head tube), chimney diameter, and radii or curvature of the ends of the chimney and any designed restriction in the "throat" of the instrument, such as that in the Japanese [[Nohkan]] flute.

A study in which professional flutists were blindfolded could find no significant differences between flutes made from a variety of metals.<ref>{{Cite journal
 | author = Widholm, G. |author2=Linortner, R. |author3=Kausel, W. |author4=Bertsch, M.
 | year = 2001 
 | title = Silver, gold, platinum—and the sound of the flute
 | journal = Proc. International Symposium on Musical Acoustics
 | pages = 277–280
 | url = http://iwk.mdw.ac.at/Forschung/english/linortner/linortner_e.htm
 | archive-url = https://web.archive.org/web/20080313014949/http://iwk.mdw.ac.at/Forschung/english/linortner/linortner_e.htm
 | archive-date = 13 March 2008
 }}</ref> In two different sets of blind listening, no flute was correctly identified in a first listening, and in a second, only the silver flute was identified. The study concluded that there was "no evidence that the wall material has any appreciable effect on the sound color or dynamic range".