Editing Glissando (section)

==Continuous glissando ==

[[File:Posaune Glissando Wiki Loves Music 2017.webm|thumb|A trombone playing a glissando]]
[[Musical instrument]]s with [[:Category:Continuous pitch instruments|continuously variable pitch]] are capable of continuous glissando, sometimes called [[portamento]], over a substantial range. These include unfretted [[chordophones]] (such as the [[violin]], [[viola]], [[cello]] and [[double bass]], and [[fretless guitar]]s), stringed instruments with a way of stretching the strings (such as the [[guitar]], [[veena]], [[sitar]] or [[pipa]]), a fretted guitar or [[lap steel guitar]] when accompanied with the use of a slide, wind instruments without valves or stops (such as the [[trombone]] or [[slide whistle]]), [[timpani]] (kettledrums), electronic instruments (such as the [[theremin]], the [[ondes Martenot]], [[synthesizer]]s and [[keytar]]s), the [[water organ]], and the [[human voice]].

Wind instruments can effect a similar limited slide by altering the lip pressure (on [[trumpet]], for example) or a combination of [[embouchure]] and rolling the head joint (as on the flute), while others such as the [[clarinet]] can achieve this by slowly dragging fingers off tone holes or changing the oral cavity's resonance by manipulating tongue position, [[embouchure]], and throat shaping.<ref name=Chen>{{cite web|last=Chen|first=Jer Ming|title=How to play the first bar of Rhapsody in Blue|url=http://www.acoustics.org/press/155th/chen.htm|publisher=Music Acoustics, School of Physics, UNSW|access-date=28 April 2013|archive-url=https://web.archive.org/web/20130425041259/http://www.acoustics.org/press/155th/chen.htm|archive-date=25 April 2013|url-status=dead}}</ref>

Many [[Electric guitar|electric guitars]] are fitted with a [[tremolo arm]] which can produce either a portamento, a [[vibrato]], or a combination of both (but not a true [[tremolo]] despite the name).

Prescriptive attempts to distinguish the glissando from the [[portamento]] by limiting the former to discrete, stepped glides conflict with established usage of the term for instruments like the [[trombone]] and [[timpani]].<ref>''Harvard Dictionary of Music'', edited by Willi Apel (Cambridge, Massachusetts, Harvard University Press, 1944): 298 or 595{{Contradict-inline|date=January 2016}}</ref> The clarinet gesture that opens ''[[Rhapsody in Blue]]'' was originally notated as a stepped glissando (Gershwin's score labels each individual note) but is in practice played as a portamento.<ref>{{cite book |author=Greenberg, Rodney| year=1998| title=George Gershwin| publisher=Phaidon Press| isbn=0-7148-3504-8| pages=70}}</ref>