Dolby Pro Logic is a surround sound processing technology designed to decode soundtracks encoded with Dolby Surround. Dolby Surround Stereo was originally developed by Dolby Laboratories in 1976 for analog cinema sound systems. The format was adapted for home use in 1986 as Dolby Surround which was then replaced by the newer and improved Pro Logic system. However, the term "Dolby Surround" is still used to describe the encoding technology or matrix-encoded soundtrack, whereas Pro Logic refers to the decoding technology/processor. Image File history File links Prologic. ... It has been suggested that Multichannel audio be merged into this article or section. ... Sign for Dolby Surround Dolby Surround was the earliest consumer version of Dolbys multichannel analog film sound format Dolby Analog SR (Spectral Recording). ... Dolby Laboratories, Incorporated (Dolby Labs) is a company specializing in audio compression and reproduction. ... 1976 (MCMLXXVI) was a leap year starting on Thursday. ... 1986 (MCMLXXXVI) was a common year starting on Wednesday of the Gregorian calendar. ... Sign for Dolby Surround Dolby Surround was the earliest consumer version of Dolbys multichannel analog film sound format Dolby Analog SR (Spectral Recording). ...

Dolby Surround/Pro Logic is based on basic Matrix technology. When a Dolby Surround soundtrack is created, four channels of sound are matrix-encoded into an ordinary stereo (two channel) sound track by using phase shift techniques. A Pro Logic decoder/processor "unfolds" the sound into the original 4.0 surround—left and right, center, and a single limited frequency-range mono rear channel—while systems lacking the decoder play back the audio as standard Stereo. In sound recording, a matrix can refer to a disc in the early stages of processing a record for mass production; see mastering and pressing process discussion at gramophone record. ... Label for 2. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

Although Dolby Surround was introduced as an analog format, all Dolby Digital decoders incorporate a digitally implemented Dolby Surround Pro Logic decoder for digital stereo signals that carry matrix-encoded Dolby Surround.

Dolby Pro Logic II

In 2000, Dolby introduced Dolby Pro Logic II (DPL II), an improved implementation of Dolby Pro Logic. DPL II processes any high quality stereo signal source into "5.1"—five separate full frequency channels (left, center, right, left surround and right surround) plus one low-frequency-effects (deep bass) channel. Dolby Pro Logic II also decodes 5.1 channels from stereo signals encoded in traditional four-channel Dolby Surround. DPL II implements greatly enhanced steering compared to DPL, and as a result, offers an exceptionally stable sound field that simulates 5.1 channel surround sound to a much more accurate degree than the original Pro Logic. Image File history File links Dolbypl2. ...

Because of the limited nature of the original DPL, many consumer electronics manufactures introduced their own processing circuitry, such as the "Jazz", "Hall", and "Stadium" modes found on most common home audio receivers. DPL II forgoes this type of processing and replaces it with simple servo (negative feedback) circuits used to derive five channels. In addition to five full range playback channels, Pro Logic II introduced a Music mode which would not add any processing to the left and right channels, but will still extract a centre channel and two surround channels, providing a net effect of a wider center channel.

The Pro Logic II system also features a mode designed specifically for video gaming, and it is frequently used in game titles for Sony's PlayStation 2, Microsoft's Xbox, Xbox 360, Nintendo's GameCube and just recently the Wii as an alternative to digital technologies like Dolby Digital. It has been suggested that Multiplayer game be merged into this article or section. ... The two versions of the PS2 with an Eye Toy camera The PlayStation 2 (PS2) (Japanese: プレイステーション2) is Sonys second video game console, after the PlayStation. ... Xbox and a Controller S The Xbox is Microsofts game console, released on November 15, 2001. ... Xbox 360 is Microsofts successor to their Xbox video game console, previously referred to during development as Project Xenon. The console is expected to be released in November 2005 in the U.S., Europe, and Japan. ... The Nintendo GameCube , GCN) is Nintendos fourth home video game console, belonging to the sixth generation era. ... The Wii (pronounced as the pronoun we, IPA: ) is the fifth video game console released by Nintendo. ... Dolby Digital logotype Dolby Digital is the marketing name for a series of lossy audio compression technologies by Dolby Laboratories. ...

Dolby Pro Logic IIx

A newer Dolby Pro Logic IIx system is also now available, which can take stereo and Dolby Surround (sometimes called Dolby Stereo Surround) source material and up-convert it to 5.1, 6.1, or 7.1 channel surround sound. Image File history File links L1_g_dolbyprologic2x. ...

Pro Logic IIx was also possible on Gamecube, as Rogue Squadron 3 proved (a game made by the team who did GC's DSP)^{[citation needed]}. Nintendo's Wii is backward-compatible with Gamecube and uses a upgraded version of the previous sound tools.^{[citation needed]}

Software Encoding

The liba52 decoder library for AC3 and A52 digital sound optionally exports stereo sound compatible with Dolby Surround and Pro Logic. [1] Sign for Dolby Surround Dolby Surround was the earliest consumer version of Dolbys multichannel analog film sound format Dolby Analog SR (Spectral Recording). ...

Minnetonka Audio SurCode software allows several commercial software packages to downmix multichannel audio to a Pro Logic 2 stereo signal.

Pro Logic Vs. Dolby Surround

Dolby Surround is the encoding counterpart to Dolby Pro Logic's decoding technology, but early home implementations of Dolby Surround decoding went by the name Dolby Surround which can cause some confusion. Dolby Surround and Dolby Pro Logic decoders are similar in principle, as both use matrix technology to extract extra channels from stereo-encoded audio. However, Pro Logic uses advanced algorithms, superior to the earlier home Dolby Surround system and similar to the original cinema Dolby Stereo processors, in order to not only extract the extra channels, but to also improve steering and discreteness between the channels. Image File history File links Download high-resolution version (1027x538, 81 KB) Dolby Surround Logo This is a logo of an organization, item, or event, and is protected by copyright and/or trademark. ... Image File history File links Prologic. ... Sign for Dolby Surround Dolby Surround was the earliest consumer version of Dolbys multichannel analog film sound format Dolby Analog SR (Spectral Recording). ...

Dolby Surround At A Glance

Dolby Encoding Matrices

j = + 90º phase-shift , k = - 90º phase-shift

j = + 90º phase-shift , k = - 90º phase-shift

j = + 90º phase-shift , k = - 90º phase-shift

See also

• Dolby Digital
• AV Receivers

Dolby Digital logotype Dolby Digital is the marketing name for a series of lossy audio compression technologies by Dolby Laboratories. ... // Overview AV Receivers are one of the many consumer electronics components typically found within a home theatre system. ...

External links

• Dolby's official site
• A Listener's Guide To Pro Logic II