Editing Aerophone (section)

==Overview==
Aerophones are one of the four main classes of instruments in the original [[Hornbostel–Sachs]] system of [[musical instrument classification]], which further classifies aerophones by whether or not the vibrating air is contained within the instrument. The first class ('''41''') includes instruments which, when played, do ''not'' contain the vibrating air. The [[Bullroarer (music)|bullroarer]] is one example. These are called ''free aerophones''. This class includes ('''412.13''') [[free reed]] instruments, such as the [[harmonica]], but also many instruments unlikely to be called wind instruments at all by most people, such as [[Siren (noisemaker)|sirens]] and [[Whip (instrument)|whips]]. The second class ('''42''') includes instruments that contain the vibrating air when being played. This class includes almost all instruments generally called [[wind instrument]]s&nbsp;— including the [[didgeridoo]], ('''423''') [[brass instruments]] (e.g., [[trumpet]],<ref name="Nzewi Nzewi 2007 p. 98"/> [[french horn]], [[baritone horn]], [[tuba]], [[trombone]]), and ('''421''' & '''422''') [[woodwind instruments]] (e.g., [[oboe]],<ref name="Nzewi Nzewi 2007 p. 98"/> [[flute]],<ref name="Nzewi Nzewi 2007 p. 98"/> [[saxophone]], [[clarinet]]<ref name="Nzewi Nzewi 2007 p. 98"/>).<ref>{{cite book|last1=von Hornbostel|first1=Erich M.|author-link1=Erich M. von Hornbostel|last2=Sachs|first2=Curt|author-link2=Curt Sachs|title=Zeitschrift für Ethnologie|chapter-url=https://archive.org/stream/zeitschriftfre46berluoft#page/552/mode/2up|access-date=April 12, 2015|volume=46|pages=582–590|year=1914|publisher=Berliner Gesellschaft für Anthropologie, Ethnologie und Urgeschichte|language=de|chapter=Abhandlungen und Vorträge. Systematik der Musikinstrumente. Ein Versuch.}}</ref> The wind factor is not only provided by the players' lungs function. The [[Organ (music)|organ]] and the [[Harmonica|mouth harmonica]] are also aerophones, both supplied with free reeds, which are blown by a mechanical system.

Additionally, very loud and impulsive sounds can be made by explosions directed into, or being detonated inside of resonant cavities. Detonations inside the [[Calliope (music)|calliope]] (and [[steam whistle]]), as well as the [[pyrophone]], might thus be considered as class 42 instruments, despite the fact that the "wind" or "air" may be steam or an air-fuel mixture.

Other cases of aerophones with impulsive sounds are the [[boomwhacker]]s and the so-called [[thongophone]]s, made up of cylindrical pipes that are struck on the sides (boomwhackers) or extremes (thongophones), thus generating percussive aerophonic tones.{{Citation needed|date=June 2015}}