Editing 5.1 surround sound

{{Short description|Sound systems that use 5 speakers and one subwoofer}}
{{Use dmy dates|date=June 2023}}
[[File:5 1 channels (surround sound) label.svg|thumb|Most common [[loudspeaker]] configuration for 5.1; used by [[Dolby Digital]], [[Sony Dynamic Digital Sound|SDDS]], [[DTS, Inc.|DTS]], and [[Dolby Pro Logic#Dolby Pro Logic II|Dolby Pro Logic II]]. The white square in the center of the diagram depicts the low-frequency speaker. Each black square depicts a loudspeaker. The center speaker in the top line of the diagram is used for dialogue. The left and right speakers on either side of the center speaker are used to create stereo sound for music and other sound effects in the film. The left and right surround speakers in the bottom line create the surround sound effect.]]

'''5.1 surround sound''' ("five-point one") is the common name for [[surround sound]] audio systems. 5.1 is the most commonly used layout in [[home cinema|home theatres]].<ref>{{Cite web|url=https://www.tested.com/tech/1242-surround-sound-examined-51-vs-71-vs-virtual-surround/|title=Surround Sound Examined: 5.1 vs 7.1 vs Virtual Surround - Tested.com|website=Tested|language=en|access-date=6 June 2019|archive-date=30 November 2012|archive-url=https://web.archive.org/web/20121130033933/https://www.tested.com/tech/1242-surround-sound-examined-51-vs-71-vs-virtual-surround/|url-status=dead}}</ref> It uses five full-bandwidth channels and one [[low-frequency effects]] channel (the "point one").<ref>{{cite web|url=http://www.crutchfield.com/S-bDkeT92VqJj/learn/learningcenter/home/hometheater_surround.html |title=Understanding Surround Sound Formats |publisher=Crutchfield.com |date=23 September 2009 |access-date=7 March 2011}}</ref> [[Dolby Digital]], Dolby [[Dolby Pro Logic#Dolby Pro Logic II|Pro Logic II]], [[DTS, Inc.|DTS]], and [[Sony Dynamic Digital Sound|SDDS]] all common 5.1 systems. 5.1 is also the standard surround sound audio component of [[digital broadcast]] and music.<ref>{{cite web |url=http://www.5dot1.com/what_is_5_1_.html |archive-url=https://web.archive.org/web/20120317220352/http://www.5dot1.com/what_is_5_1_.html |archive-date=17 March 2012 |title=What is 5.1}}</ref>

All 5.1 systems use the same speaker channels and configuration, having a Front Left ('''FL''') and Front Right ('''FR'''), a [[center channel|Center Channel]] ('''CNT'''), two [[surround channels]] (Surround Left - '''SL''' and Surround Right - '''SR''') and the [[low-frequency effects]] ('''LFE''') channel designed for a [[subwoofer]].<ref>{{Cite web |title=Help Guide {{!}} Names and functions of speakers |url=https://helpguide.sony.net/ha/strdh77/v1/en/contents/TP0001042609.html |access-date=12 June 2023 |website=helpguide.sony.net}}</ref><ref name=":0">{{Cite web |title=Help Guide {{!}} Installing 5.1-channel speaker system |url=https://helpguide.sony.net/ha/strdh77/v1/en/contents/TP0000965687.html |access-date=12 June 2023 |website=helpguide.sony.net}}</ref>

==History==
A prototype for five-channel surround sound, then dubbed "quintaphonic sound", was used in the 1975 film ''[[Tommy (1975 film)|Tommy]]''<ref>{{cite journal |title=Quintaphonic Sound |last=Mosely |first=John |journal=Journal of the SMPTE |volume=86 |date=January 1977 }}</ref> however, it had no dedicated subwoofer channel and used only two surround speakers in the rear corners of the auditorium thus causing the same problems with audience coverage uniformity that had been fixed in [[Fantasound]] (1939) by using surround arrays.

The name 5.1 was given in a [[Society of Motion Picture and Television Engineers]] (SMPTE) Committee on Digital Sound on Film in 1987 by [[Tomlinson Holman]]. There was an early Dolby application of optical matrix encoding in 1976 (released on the film ''[[Logan's Run (film)|Logan's Run]]''), but it did not use split surrounds, and thus was not true 5.1. Dolby first used split surrounds with 70 mm film, notably in 1978 with [[Superman (1978 film)|Superman]] and then in 1979 with ''[[Apocalypse Now]]''. Instead of the five screen channels and one surround channel of the [[Todd-AO]] format, [[Dolby Stereo#Dolby Stereo 70 mm Six Track|Dolby Stereo 70 mm Six Track]] provided three screen channels, two high-passed surround channels, and a monophonic low-frequency channel.

The first system with digital 5.1 surround sound was [[Dolby Digital]] in 1992 with [[Batman Returns]], followed by [[DTS, Inc.|DTS]] in [[Jurassic Park (film)|Jurassic Park]] in 1993, and [[SDDS]] with [[Last Action Hero]] in 1993. [[Kodak]] and Optical Radiation Corporation introduced [[Cinema Digital Sound]] (CDS) in 1990 with [[Dick Tracy (1990 film)|Dick Tracy]], but it had no analog backup and after failing on opening day it was phased out shortly thereafter.  

[[Tomlinson Holman]] built a four-channel panner in 1982 for [[Return of the Jedi]] using parts from his earlier Apt/Holman preamplifier. It was extended to 5.1 by Sound Workshop (with proper credit) and SSL in its 5000 Series (with no credit). The console included ABCDEF channels: respectively, A left, B right, C centre, D left rear, E right rear, F bass.  

When digital sound was applied to 35&nbsp;mm release prints, with ''[[Batman Returns]]'' in 1992, the 5.1 layout was adopted. The ability to provide 5.1 sound had been one of the key reasons for using 70&nbsp;mm for prestige screenings. The provision of 5.1 digital sound on 35&nbsp;mm significantly reduced the use of the more expensive 70&nbsp;mm format.

5.1 digital surround, in the forms of Dolby Digital AC-3 and DTS, started appearing on several mid-1990s [[LaserDisc]] releases, among the earliest being ''[[Clear and Present Danger (film)|Clear and Present Danger]]'' and ''[[Jurassic Park (film)|Jurassic Park]]'' (the latter having both AC3 and DTS versions). Many DVD releases have Dolby Digital tracks up to 5.1 channels, due to the implementation of Dolby Digital in the development of the DVD format. In addition, some DVDs have DTS tracks, with most being 5.1 channel mixes (a few releases, however, have 6.1 "[[Matrix decoder|matrixed]]" or even discrete 6.1 tracks). [[Blu-ray]] and [[digital cinema]] both have eight-channel capability which can be used to provide either 5.1 or [[7.1 surround sound]]. 7.1 is an extension of 5.1 that uses four surround zones: two at the sides and two at the back.

==Application==

===Channel order===
The order of channels in a 5.1 file is different across file formats. The order in [[WAV file]]s is (not complete) Front Left, Front Right, Center, [[Low-frequency effects]], Surround Left, Surround Right.<ref>{{cite web|url=https://docs.microsoft.com/en-us/previous-versions/windows/hardware/design/dn653308(v=vs.85)|title=Multiple channel audio data and WAVE files|access-date=19 November 2015}}</ref>

=== Music ===
[[File:5-1-surround-sound.svg|thumb|Suggested configuration for 5.1 music listening]]

In music, the main goal of 5.1 surround sound is a proper localization and equability of all acoustic sources for a center-positioned audience. Therefore, ideally five matched speakers should be used.

=== Speaker placement ===
For playback the [[International Telecommunication Union]] (ITU) recommends the following configuration (ITU-R BS 775):<ref>{{citation |url=http://www.aes.org/e-lib/browse.cfm?elib=9095 |author=Thomas Lund |title=Enhanced Localization in 5.1 Production |publisher=Audio Engineering Society |date=1 September 2000 |access-date=19 November 2015 |url-access=subscription }}</ref><ref name=":0" />
* five speakers of the same size for front, center and surround
* identical distance from the listeners for all five speakers
* angle adjustment regarding viewing direction of audience: center 0°, front ±22.5° for movies ±30° for music, surround ±110°

== See also ==
* [[7.1 surround sound]]
* [[Ambisonics]]
* [[Stereophonic sound]]
* [[Timeline of audio formats]]

== References ==
{{Reflist}}

[[Category:Consumer electronics]]
[[Category:High-definition television]]
[[Category:Surround sound]]
[[Category:Ultra-high-definition television]]