Editing Aerophone (section)

===Free===
Free aerophones are instruments where the vibrating air is not enclosed by the instrument itself.

====Displacement====
The air-stream meets a sharp edge, or a sharp edge is moved through the air.

====Interruptive====
The air-stream is interrupted periodically.

====Plosive====
Also known as percussive aerophones, plosive aerophones are percussion instruments sounded by a single compression and release of air.<ref name="See Sharp Press 1996 p. 85"/> An example of a plosive aerophone is the scraper flute which has tubes with ridged or [[serration|serrated]] edges so that they can be scraped with a rod to produce sound.<ref>{{cite web |url= http://windworld.com/bart/invented-instruments/difficult-to-categorize-scraper-flutes/ |title= Scraper Flutes |author= Bart Hopkin |access-date= 29 April 2015 |archive-url= https://web.archive.org/web/20150407065050/http://windworld.com/bart/invented-instruments/difficult-to-categorize-scraper-flutes/ |archive-date= April 7, 2015 |url-status= dead |df= mdy-all }}</ref><ref name="Hopkin1996">{{cite book|author=Bart Hopkin|title=Musical Instrument Design: Practical Information for Instrument Making|url=https://books.google.com/books?id=CuHi9edzELEC&pg=PA86|date=1 January 1996|publisher=See Sharp Press|isbn=978-1-884365-08-9|page=86}}</ref>

Another example of a percussive aerophone is the so-called [[thongophone]], consisting of a cylindrical pipe that is struck by a special mallet, somehow equivalent to a [[Flip-flops|flip-flop]] (thong). A thongophone may sound like an open-open pipe if the mallet is quickly removed after striking the pipe's extreme. Also, it may sound as an open-closed pipe, if the mallet remains closing the pipe after the attack. In the first situation (open-open), the first resonance mode will have a wavelength that corresponds to two times the pipe length, approximately. It is called by acousticians as a "half-wavelength" air column. In the second situation (open-closed), the first resonance mode will have a wavelength that corresponds to four times the pipe length, approximately.  Acousticians call it as "quarter-wavelength" air-column.