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right and surround channels to be lowered. This increases the channel separation achievable to around 30 decibels between channels. By careful tuning of the response of the amplifiers, the total amount of signal energy remains constant and is unaffected by the operation of the channel steering. Additionally, the response time of the system to changes in sound direction is important as too fast a response results in a twitchy feel, while too slow a response leaves sounds coming from an inappropriate direction.
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617:. DPL II processes any high-quality stereo signal source into five separate full frequency channels (right front, center, left front, right rear and left rear), while also decoding five 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 five-channel surround sound.
390:. It was capable of decoding Dolby Stereo four-channel soundtracks to three output channels (Left, Right, Surround). The Center channel was fed equally to the Left and Right speakers. The Surround channel was limited to a 100 Hz to 7 kHz frequency bandwidth, as dialog from the center channel could leak into the surround channel—there was as little as 3 dB of separation between LCR and Surround channels.
272:
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. One of the first was the MSP400 surround sound receiver and amplifier by RCA
620:
Because of the limited nature of the original Dolby Pro Logic encoding, many consumer electronics manufacturers 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
498:
A Pro Logic decoder also uses 'Steering Logic', which drives amplifiers to raise or lower the output volume of each channel based on the current dominant sound direction. For example, while a mono signal is played, the strong correlation to the center channel triggers the output volume of the left,
227:
and an adjustable delay, for improved channel separation and to prevent dialog leaking and arriving to listeners' ears first. The front center channel was equally split between the left and right channels for phantom center reproduction. This differed from the Cinema Dolby Stereo system which used
510:
Dolby
Surround and Dolby Pro Logic decoders are similar in principle, as both use matrix technology to extract extra channels from Dolby Stereo stereo-encoded audio. The terms Dolby Stereo, Dolby Surround and Lt/Rt are all used to describe soundtracks that are matrix-encoded using this technique.
854:
above the front left and right speakers, expanding a 5.1 or 7.1 system to 7.1 Height or 9.1. It identifies spatial cues in low-level, uncorrelated information, such as ambience and effects like rain or wind in the side and rear surround channels, and directs it to the front height speakers. The
231:
Later on in 1987, the Pro Logic decoding system was released to consumers. It featured virtually the same type of four-channel decoding as the Dolby Stereo theater processor with active steering logic and much better channel separation (up to 30 dB) as well as including a dedicated center
232:
channel output for the first time. Many standalone Pro Logic decoders also included a phantom center option for compatibility with earlier non-Pro Logic Dolby
Surround equipped home theaters to split the center channel signal to the L/R speakers for legacy phantom center reproduction.
629:) circuits used to derive five channels. The extra channel content is extracted using the difference between the spatial audio content between two individual channels of stereo tracks or Dolby Digital encoded 5.1 channel tracks and outputs it appropriately.
502:
In addition to 5 dB of noise reduction, the surround channel is slightly delayed, so that any front channel sounds that leak into the surround channel arrive at the listener after the front channels. This takes advantage of the
632:
In addition to five full-range playback channels, Pro Logic II introduced a Music mode that includes optimized channel delays and adds user controls to—for example—adjust apparent sound stage width.
215:
theater system on a 35mm optical stereo print and decoded back to the original 4.0 Surround. The same four-channel encoded stereo track was largely left unchanged and made available to consumers as
258:
to the left channel and a −90-degree phase shift to the right channel). The surround channel was often used for ambient background sounds in the original recording, music scores and effects.
246:(two-channel) soundtrack. The center channel is reduced in level by 3 dB and summed to the left and right channels; the surround channel is attenuated by 3 dB, passes through a
753:
system, available since 2003, can take two-channel stereo, Dolby
Surround (sometimes called Dolby Stereo Surround) and Dolby Digital 5.1 source material and up-convert it to 6.1 or
1116:
374:
is the earliest consumer version of Dolby's surround sound decoding technology. It was introduced to the public in 1982 during the time home video recording formats (such as
507:—audio that is present in the front speakers but delayed in the surround speakers will have the psychoacoustic effect of emanating from the front of the sound stage.
386:
capability. The name Dolby
Surround described the consumer passive matrix decoding technology; the professional, active-matrix cinema technology bore the name
994:
Dolby
Digital (AC3) compatible hardware (DVDs, TVs, Blu-ray players) downmixes the 5.1 channel tracks into Lt/Rt stereo compatible with Pro Logic decoders
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is the full name that refers to the matrix surround format and decoding system in one. When a Dolby
Surround soundtrack is created in post-production (
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on home video. However, the original Dolby
Surround decoders in 1982 were a simple passive matrix three-channel decoder: L/R and mono
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noise reduction and is encoded on the left and right channels with opposite polarity (this is achieved by applying a +90-degree
1004:
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are capable of downmixing Dolby
Digital AC-3 5.1 to Lt/Rt stereo tracks compatible with Dolby Pro Logic I & II decoders.
954:
is a complete replacement for Pro Logic that upmixes stereo and multi-channel inputs to play over Atmos configurations.
967:
decoder library for AC3 and A52 digital sound optionally exports Lt/Rt stereo sound compatible with Pro Logic decoders.
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251:
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SurCode for Dolby Pro Logic II is a Dolby-certified software encoder and decoder available in plug-in formats for
261:
A Dolby Pro Logic decoder/processor "unfolds" the soundtrack back into its original 4.0 surround—left and right,
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active steering and other processing to decode a center channel for dialog and center focused on screen action.
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A Pro Logic decoder/processor "unfolds" the sound into the original 4.0 surround—left and right,
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was the professional system that encoded four channels of film sound into two. This track used by the
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269:) mono rear channel—while systems lacking the decoder play back the audio as standard stereo.
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659:. Game mode is similar to Movie mode, except it redirects more bass to the LFE channel.
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terminology in 2014. The term now refers to a new upmixer whose purpose is to enable
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expands on Pro Logic IIx with the addition of a height component, creating front
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162:) are also used to describe soundtracks that are encoded using this technique.
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613:(DPL II), an improved implementation of Dolby Pro Logic created by
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receivers and speaker configurations to serve non-Atmos signals.
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Pro Logic II systems also have a mode designed specifically for
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242:), four channels of sound are matrix-encoded into an ordinary
223:. The surround channel was limited to 7 kHz. It also had
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sound systems. The format was adapted for home use in 1982 as
1288:
1117:"Dolby Surround Pro Logic Decoder – Principles of Operation"
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Surround sound processing technology developed by Dolby Labs
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Older logo, before Dolby updated their overall logo design.
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In 1987 the decoding technology was updated and renamed
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Home theatre focus' history of dolby surround decoders
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as an alternative to digital surround formats such as
19:"Pro Logic" redirects here. Not to be confused with
1216:"Tech Blog – TV/DVD Surround Encoding Technologies"
491:, and a single limited frequency-range (7 kHz
265:, and a single limited frequency-range (7 kHz
200:were introduced. It was further improved with the
957:
27:Dolby Surround/Dolby Pro Logic/Dolby Pro Logic II
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138:, designed to decode soundtracks encoded with
1273:
855:channels it adds are matrixed, not discrete.
184:)—was developed by Dolby in 1976 for analog
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1054:Cohen, Simon; Hall, Parker (2023-11-10).
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1214:Neyrinck, Paul (February 26, 2015).
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1005:Dolby encoding and decoding matrices
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134:processing technology developed by
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1083:"Surround Sound Explained: Part 2"
393:
14:
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1474:Audiovisual introductions in 1986
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1081:Robjohns, Hugh (September 2001).
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279:Digital Command Component System
1248:Dolby's official history page 4
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1154:Scarpelli, Paul (2015-03-03).
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958:Software encoding and decoding
382:) were introducing Stereo and
1:
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204:decoding system after 1987.
1343:Dolby noise-reduction system
7:
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639:which is used in games for
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609:In 2000, Dolby introduced
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1183:"Dolby Pro Logic IIz"
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495:) mono rear channel.
225:Dolby Noise Reduction
182:stereo variable-area
1195:on January 22, 2009
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273:for their high-end
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1469:Dolby Laboratories
1363:Dolby Surround 7.1
1328:Dolby Digital Plus
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1135:on March 26, 2014
1115:Dressler, Roger.
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1193:the original
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1137:. Retrieved
1130:the original
1123:
1092:. Retrieved
1086:
1076:
1065:. Retrieved
1059:
951:
950:
941:
939:
911:Dolby Stereo
869:Product type
847:
846:
822:Dolby Stereo
780:Product type
750:
748:
724:Dolby Stereo
682:Product type
634:
631:
621:with simple
619:
610:
608:
576:Dolby Stereo
534:Product type
509:
501:
497:
486:
481:
479:
455:Dolby Stereo
413:Product type
388:Dolby Stereo
371:
370:
346:Dolby Stereo
304:Product type
271:
260:
239:
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234:
230:
216:
213:Dolby Stereo
212:
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177:
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166:Dolby Stereo
165:
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155:
149:
145:Dolby Stereo
143:
142:. The terms
139:
127:
126:
98:Dolby Stereo
32:Product type
1388:Doremi Labs
1378:Dolby Voice
1303:Dolby Atmos
1199:January 22,
1161:Audioholics
1139:February 8,
1028:AV receiver
1015:Dolby Atmos
946:Dolby Atmos
915:Dolby Atmos
637:video games
615:Jim Fosgate
505:Haas effect
256:phase shift
160:Right Total
1453:Categories
1406:CinePlayer
1401:CineExport
1094:2024-01-06
1067:2024-01-06
1039:References
895:Introduced
806:Introduced
708:Introduced
560:Introduced
439:Introduced
330:Introduced
156:Left Total
58:Introduced
1422:Ray Dolby
1396:CineAsset
1167:March 17,
971:HandBrake
924:Worldwide
831:Worldwide
733:Worldwide
585:Worldwide
464:Worldwide
355:Worldwide
178:Dolby SVA
111:Worldwide
21:Logic Pro
1353:Dolby SR
1313:Dolby 3D
1308:Dialnorm
1220:Neyrinck
999:See also
645:GameCube
275:Dimensia
221:Surround
170:Dolby MP
1333:Dolby E
929:Website
921:Markets
887:Country
836:Website
828:Markets
798:Country
738:Website
730:Markets
700:Country
590:Website
582:Markets
552:Country
469:Website
461:Markets
431:Country
376:Betamax
360:Website
352:Markets
322:Country
252:Dolby B
116:Website
108:Markets
50:Country
1415:People
975:FFmpeg
965:liba52
647:, and
489:center
263:center
244:stereo
186:cinema
1431:Other
1133:(PDF)
1120:(PDF)
1023:Neo:6
877:Owner
788:Owner
690:Owner
623:servo
542:Owner
421:Owner
312:Owner
192:when
176:) or
130:is a
40:Owner
1227:2017
1201:2009
1169:2017
1141:2019
982:DAWs
973:and
963:The
898:2014
809:2009
749:The
711:2003
563:2000
442:1987
384:HiFi
378:and
333:1982
207:The
198:VCRs
194:HiFi
151:LtRt
148:and
102:LtRt
61:1982
1020:DTS
657:DTS
655:or
649:Wii
380:VHS
1455::
1218:.
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1158:.
1122:.
1103:^
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1058:.
1046:^
757:.
643:,
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281:.
158:,
1281:e
1274:t
1267:v
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154:(
23:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
