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 theatres. It uses five full bandwidth channels and one low-frequency effects channel (the \"point one\"). Dolby Digital, Dolby Pro Logic II, DTS, SDDS, and THX are all common 5.1 systems. 5.1 is also the standard surround sound audio component of digital broadcast and music.
All 5.1 systems use the same speaker channels and configuration, having a front left and right, a center channel, two surround channels (left and right) and the low-frequency effects channel designed for a subwoofer.
5.1 dates back to 1976, when Dolby Labs modified the track usage of the six analogue magnetic soundtracks on Todd-AO 70 mm film prints. The Dolby application of optical matrix encoding in 1976 (released on the film Logan's Run) did not use split surrounds, and thus was not 5.1. Dolby first used split surrounds with 70 mm film, notably in 1979 with Apocalypse Now. Instead of the five screen channels and one surround channel of the Todd-AO format, Dolby Stereo 70 mm Six Track provided three screen channels, two high-passed surround channels and a low-frequency surround channel monophonically blended with the two surround channels.
A system of digital 5.1 surround sound was also used in 1987 at the Parisian cabaret the Moulin Rouge, created by French engineer Dominique Bertrand. To achieve such a system in 1985, a dedicated mixing console had to be designed in cooperation with Solid State Logic, based on their 5000 series, and dedicated speakers in cooperation with APG. The console included ABCDEF channels: respectively, A left, B right, C centre, D left rear, E right rear, F bass. The same engineer had already developed a similar 3.1 system in 1973, for use at the official International Summit of Francophone States in Dakar.
The channels in a 5.1 audio mix serve distinct purposes. The three front channels (Left, Center, and Right) provide crisp, clean dialogue and accurate placement of onscreen sounds. The twin surround channels (Left Surround and Right Surround) create the sense of being in the middle of the action.
Dolby ProLogic technologyThis consists of four discrete channels of audio (left, right, center and rear). This matrix multi-channel sound is encoded down to two channels for distribution, and then is decoded back to four channels when played back on a stereo source that decodes Dolby ProLogic technology surround.
Dolby Digital (AC3, 5.1) technologyThis is a multi-channel surround system that contains 6 discrete channels of audio (left front, right front, center, left rear, right rear and LFE subwoofer). Dolby Digital technology is commonly referred to as 5.1 (five point one) surround sound because it contains 5 full bandwidth (20 - 20,000 Hz) for the front, center and rear speakers, and one low frequency effects (LFE) subwoofer channel that is referred to as .1 (point one).
DTS ES MatrixThis is actually a 5.1-channel format with the back surround audio channel matrixed into those of the right and left surround. The back surround channel is matrixed in similar fashion as the front center channel is matrixed into the front right and left channels in the Dolby Surround Pro-Logic technology. As such, the back surround channel is not discrete and therefore is not a true '6.1' format. DTS-ES Matrix is compatible with THX Surround EX equipment. DTS-ES Matrix is completely backwards compatible with DTS 5.1 equipment.
DTS ES Discrete 6.1This is a true 6.1-channel format, as the back surround audio channel is discretely encoded into the DTS bitstream. This format offers better stabilization over the surround channels for complete 360-degree sound localization and surround pans (i.e., movement of sound in the surround channels from one side to another). A data flag signals the decoder (usually part of the receiver or pre-amplifier) that the bitstream contains an extra discrete back surround channel. For backwards compatibility, DTS-ES Discrete 6.1 back surround channel is ignored by DTS 5.1 equipment.
DTS Neo:6This is a 7.1 configuration with two rear-center speakers that play in mono. The DTS Neo:6 works a lot like Dolby Pro Logic IIx where you can take stereo content and up-convert the sound to 5.1 or 6.1 channel surround sound format.
DTS-HD Master AudioThis is a lossless audio codec, previously known as DTS++ and is steadily becoming the standard for Blu-ray lossless audio. It is the second of two DTS-HD audio formats. This format supports an unlimited number of surround sound channels, and can downmix to 5.1 and 2-channel. This format also can deliver audio quality at bit rates extending from DTS Digital Surround up to lossless (24-bit, 192 kHz).
Dolby Digital is a multi-channel audio codec from Dolby Labs. It delivers a cinematic surround sound experience and is commonly referred to as the 'industry standard' (primarily because Dolby Labs has been around longer than DTS).
Both DTS and Dolby Digital are audio compression technologies, allowing moviemakers to record surround sound that can be reproduced in cinemas as well as homes. Both deliver spine-tingling multi-channel sound, so what's the difference And which is better
In their most basic form, both DTS and Dolby Digital support 5.1-channel audio (i.e. a typical home cinema system with five speakers and one subwoofer). And more advanced versions of the formats support 7.1-channels, HD surround sound and overhead speakers, in the form of DTS:X and Dolby Atmos.
The first film to use Dolby Digital was Batman Returns in 1992. Since then, Dolby has released a slew of increasingly advanced codecs, including Dolby Digital Plus, which supports HD surround sound and up to 7.1 speaker channels.
Like Dolby Digital, DTS has since released a plethora of more advanced surround sound formats including DTS-HD High Resolution, which supports up to 7.1 speaker channels. DTS has also brought out a lossless format, DTS-HD Master Audio. There is also DTS:X, which competes with Dolby's Atmos.
Dolby Digital is often referred to as a 5.1 channel surround system. However, the term Dolby Digital refers to the digital encoding of the audio signal, not the number of channels it has. Dolby Digital may also be referred to as DD, DD 5.1, or AC3.
DTS, on the other hand, offered two separate 6.1 versions. DTS-ES Discrete and DTS-ES Matrix perform as their names suggest. With ES Discrete, specific sound information is programmed onto a DVD or Blu-ray disc, while DTS-ES Matrix uses the same technique as Dolby Digital EX to extrapolate information from the surround channels.
Unfortunately, this makes for a signal that is more difficult to transmit. For most TVs, sending a PCM signal to or from a TV will downgrade the signal to 2.1 for two speakers and a subwoofer, thus eliminating the extra channels necessary for surround sound.
If you are using Apple AirPlay or AirPlay 2 to stream from an iOS device to an Apple TV or other compatible AirPlay device (Airplay 2 enabled TV), surround sound is not supported, you will only hear two-channel stereo audio.
Discrete surround sound keeps each channel separate from start to finish.This improved channel separation, whichever format is used, results in a morerealistic surround effect. In the home, all discrete surround formats havealways been digital in nature—which also contributes to improved soundquality.
The most popular discrete surround format today is Dolby Digital. Asthe name implies, it's a completely digital process, as opposed to theanalog matrix technology used in the older Dolby Pro Logic format.
Dolby Digital is used in most commercial DVDs as well as some satellite andcable programming (especially by HBO, Showtime, and other pay channels), and isthe format specified for all HDTV broadcasts. In short, it's the surroundformat of choice for most forms of home entertainment programming.
There are actually several variations of Dolby Digital, depending on how manychannels are used. That's right—not all Dolby Digital soundtracksutilize a full array of surround channels. Dolby Digital is actually a flexibleformat that supports up to 5.1 channels. So mono films are often recorded inDolby Digital 1.0 (one center channel, no subwoofer), and older stereo films inDolby Digital 2.0 (left and right front channels, no subwoofer).
The most common format, however, is Dolby Digital 5.1. This format includesleft front, center front, right front, left surround, and right surroundchannels, plus a separate low frequency effects (LFE) channel that is fed toyour system's subwoofer. Add that up and you get the 5 main channels plusthe \".1\" LFE channel. (Those rare soundtracks without an LFE channelare technically designated \"5.0\"—the \"0\" noting thelack of an LFE channel.)
The Digital Theater Systems company markets a discrete surround format,called DTS, that competeshead-to-head with Dolby Digital. Like Dolby Digital 5.1, the DTS format includesfive main channels (left front, center front, right front, left surround, andright surround) plus a separate LFE channel. Although technically possible, oneseldom (if ever) sees DTS used for mono or stereo recordings.
Dolby Digital EX is a new variation of the Dolby Digital format. EXadds a \"surround rear\" channel in addition to the regular left andright surrounds. This rear channel is placed behind the listener/viewer, whilethe left and right surrounds are placed to the sides. Note, however, that thissurround channel is matrixed, not discrete, so it's not overlydirectional.
Like Dolby Digital EX, DTS ES is a 6.1 technology with an addedsurround rear channel. There is also a 7.1-channel version, with two surroundrear channels. Both versions use matrix technology to create and decode the rearchannel(s). 153554b96e