Talk:Surround sound
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[edit] LRE?
It seem that there is some alphabet soup going on. It might be valuable to provide links or explanations (as is done above for 3.1) as to what some of these letters mean.
[edit] 5.1 Speaker Placement
Surround Sound speaker placement is different for both music and movie content. For music speakers are placed in a circle around the listener. The center channel has 0º offset, left and right are offset ± 30º, and the left/right surrounds are offset by ±110º. Also all speakers should be, monopole, equidistant to the listener, and all delay (ms) calculations on the surround decoder should be turned off (0ms).
For movie surround, the front speakers should be placed at the edges of the screen, toed in to face the central listening location, and the tweeters should be ear hight. The center speaker should be placed behind the screen (when using projection) or over or under a tv, and as close to ear high as possible. Rear channel speakers should be placed high on side walls, slightly behind the listening position, and should have a di-pole construction.
For more information check out a great DVD on system calibration by the Imaging Science Foundation called Video Essentials. http://www.videoessentials.com/
AJS 16:26, 23 November 2005 (UTC) AJSchmidt Updated 13:12 (PST) 19 December 2005
Recomendations for five channel speaker systems (with or without LFE), specifically for broadcast with DTV, but which are generally adhered to by most movies are set out in the International Telecommunications Union ITU-R paper BS.775-2 (2006).
[edit] Purpose of the Music Artists section
Is there any purpose for this section in the article? There's no explanation of how these artists relate to Surround Sound and at the moment the selection looks to be quite arbitrary. --HTGuru 14:14, 6 July 2006 (UTC)
- Agreed. I'm about to remove it, and I think the entire article could use, one, cleanup, and two, major pruning. — SheeEttin {T/C} 17:55, 2 September 2006 (UTC)
- I removed the section -Orayzio 22:27, 22 September 2006 (UTC)
[edit] Question
Hello! At my computer I have 4 normal speakers + 1 subwoofer, 2 of the speakers are to my front left and the other 2 are to my front right, the subwoofer is to my front center, there are no speakers behind or beside me. How is this system called? Is it 5.1, 4.1, 5.0 or 4.0? I have no idea. Sorry for my bad english but the article in my language is even less useful. Thanks. 172.174.154.39 16:01, 16 September 2006 (UTC)
Answer: This system is a 2.1, as the source material is just 2.1 from the computer; as the material from the outputs are identical. In order to make this 4.1 you would need to have four differing speaker outputs and a subwoofer. If you could call your system 4.1, then the last front speakers at the last Madonna concert would be 112.56, but only running in 2.0 Stereo. This raises an interesting point though, for instance Volvo cars are sometimes described as 7.1 but in fact the only have a 5.1 amplifier, with the rear door and surround speakers hard-wired together. Not good.
[edit] Difference between 7.1 and 8-channel surround
Hi, I was wondering if there is a difference to true 7.1 surround sound encoding and 8-channel audio encoding? According to Surround_sound, "7.1 adds two additional side speakers or two addtional rear speakers to 5.1" and "Cinematic 8 channel audio is a commercial surround sound standard that adds two speakers to the more conventional, and consumer-oriented 6-channel (5.1) audio set-up." I understand those statements to mean that the 7.1 and 8-channel audio specifications both contain (or should) contain 8 discrete channels. Is there supposed to be a difference between the two specifications? Thanks.
- I deleted the 8.0 section because, when you read it, it was the same as 7.1. Martin.leese 07:12, 14 February 2007 (UTC)
[edit] Answer and more on theaters
I hope someone with better wiki skills can add links -thanks
Answer: Yes there is a difference in 7.1 and 8CH audio (see 8.0, 8.1, and SDDS below). These differences only appear in commercial theater playback systems. Most (more than 50% in San Francisco Bay Area as thats were i work and build systems) theaters use a 10.2 system for sound playback (although not 10.2 discreet). This consists of LR Center, LR Front, LR side (first third rows), LR Rear Side (second third rows) and, LR Back (rear wall); plus two large subs at the front LR (usually mono). This is done to accommodate the different systems of sound, and also maintain backward compatibility with optical stereo. A description of source adaptation is below.
Default speaker panning of sound systems in adaptation of sound to 10.2:
Analog:
Optical 2 track - the left and right tracks are panned over the front 4 speakers with CLR getting 60% and FLR getting 40%, a low pass sends sound the the subs.
Mag 4 track - Track 1 dialog is sent to CLR, track 2 music to FL 100%, track 3 music to FR 100%, and track 4 SFX is sent 40% to FLR 30% to SLR and the rest to RSLR and BLR, a low pass sends sound the the subs.
70mm 6ch Mag - tracks 1 and 2 form CLR, 3 and 4 goto FLR, and 5 and 6 Go to the 6 surrounds, a low pass sends sound the the subs.
2ch Matrix (Dolby ProLogic) - Dolby steering logic is used to drive the front channels as groups (CL and FL equaly get CH1 and same with the R), out of phase sounds are sent as mono to the surrounds as 20% SLR, 40% RSLR, and 40% BLR.
Other formats like Quadraphonic are supported through logical distributions of sound.
Digital:
Digital signals with analog equivalents are the same as the analog distributions.
5.0 and 5.1 (Dolby Digital, DTS) - Center is feed to CLR at 80% and the remainder is mixed into FLR, Front Left Right goes to FLR at 90% and to SRL 10%, Surrounds go to the respective sides at 30% SLR, 60% RSLR, and 10% BLR, SUB is sent to the subs in mono.
6.0 and 6.1 (DD-EX, DTS-ES) - For C and FRL see 5.1. Surround LR is sent 40% to SLR and 60% to RSLR, Back is sent to BLR in mono.
7.1 (Versions of DD and DTS) - see 6.1. Back Surrounds are in stereo and are sent to the respective BLR speaker.
8ch, 8.0, and 8.1 (SDDS) - Note SDDS is a 12ch format, but only uses 8ch. Left and Right are at 100% to FLR speakers, Left Center and Right Center is mixed into the FLR and CLR speakers, Center is sent to CLR as mono, Surround Left and Right are mixed in the same fashion as 5.1 the sub is sent to the pair as mono, SDDS has 4 other backup channels that are Center Left Right Surround, but are only used if damage has occurred to the 8 tracks. There is no home version of SDDS. - AJS
[edit] Discrete analog?
My receiver has Dolby Pro Logic, but also separate audio inputs for each channel. Wouldn't the latter be discrete analog, which isn't mentioned here? Incidentally, it would be good to say how, with the same source, matrix analog I/O compares with discrete analog I/O compares with discrete digital I/O. I know much of what is said is "opinion" and/or difficult to source, but many people (myself included) who are wondering what the listening experience difference is in making purchase decisions. Calbaer 17:42, 14 December 2006 (UTC)
Answer: My Sony receiver also has analog 5.1 inputs. The analog 5.1 inputs are actually receiving a signal decoded by the Dolby Digital processor in the DVD player. This mean the receiver is not doing the decoding, but it is left upto the source unit, in this case the DVD player. The signal is just converted to an analog signal between the DVD player and the amplifier, this the reason for having 6 cables in the hookup.
With digital inputs on a receiver, the DVD player is only sending the digital signal to the receiver where it is digitally decoded, amplified and sent as an analog signal to the appropriate speaker. In both cases, we are dealing with "Dolby Digital" not "Dolby Pro Logic." Pro Logic only supports matrixed encoding.
Both methods still use a Dolby Digital decoder somewhere in the mix, and both methods have a final result of an amplified signal sent as analog to the appropriate speaker, the conversion to analog just happens at a different point.
I now plan to add a section explaining this in the article, I feel it should appear under the Dolby Digital 5.1 section.
[edit] Merging from Multichannel audio
It was me who added {{mergefrom|Multichannel audio}} to Surround sound, so I thought I had better start a Talk section on it. The idea is that the Multichannel audio page is redundant. In January 2006 it was suggested that it be deleted, but nothing was done. My suggestion, which is now formal, is that nothing be changed in Surround sound, and that Multichannel audio becomes a simple #REDIRECT. Martin.leese 04:41, 7 January 2007 (UTC)
- Done. Martin.leese 08:03, 17 January 2007 (UTC)
[edit] Bass management and LFE
I've adjusted the bass management discussion in the specification section, to deal with some common misconceptions. It is widely believed that the LFE is connected directly to a subwoofer (ie that the LFE is the "subwoofer channel") - so much so that some music engineers who should know better actually do this in the studio, with dreadful results.
Essentially, bass management routes bass on any incoming channel to speakers that can handle it. This may be the mains or subwoofer(s). All the current surround specifications given in the article equate LFE and subwoofer, which is not the case: you can have a 5.1 system, for example, with just five, full-range speakers in the replay system and no subwoofer at all, or you could have big speakers front left and right and small ones at the rear, and all the bass comes from the front L&R - and still no sub. Or you could have two subwoofers. All these are 5.1 systems, though, because the ".1" refers to the incoming Low Frequency Effects channel.
I am loath to rewrite all these entries myself because of the time involved and the fact that this might be seen as contentious, so I'm putting it out there as a suggestion: if it meets with approval then either I or others can implement it. As it stands, I think the revised BM section tells the story correctly and hopefully people will read that before they plunge into the specs and can interpret the latter in terms of the former.
[edit] 7.1
Hi! My computer stereo speakers have broken, so I want to buy new speakers: 5.1, or 6.1, or 7.1. 7.1 is not more expensive then 5.1. BUT, is there any DVDs or computer videogames with 6.1 or 7.1 standart? Is it usefull to buy 6.1 or 7.1 instead 5.1 now? When 6.1 or 7.1 will become popular? Maybe in Blu-ray, HDDVD-movies and DirectX 10 videogames?.. Moscvitch 18:33, 19 February 2007 (UTC)
[edit] 4.1 Wrong Diagram ?
"One channel for both surround speakers at the rear - mono surround channel" There are 2 rear speakers connected to the same channel. The diagram should be same as 5.1 . Fourtildas 02:31, 27 February 2007 (UTC)
- Under Surround_sound#Surround_sound_specifications it states
A distinction is also made between the number of channels reproduced for playback and the number of speakers used to reproduce. The graphics to the right of each specification description represent the number of channels, not the number of speakers.
- So, no, the diagram is not wrong. Martin.leese 04:28, 27 February 2007 (UTC)
[edit] Possible TOC confusion
Any good ways to alter the table of contents so that all the surround sound specifications aren't so confusing to the eye (e.g. "5.1 3.0 channel Surround" or "5.1 5.5 channel Surround")… Not sure if there's a standard for this—it's not a big deal, but it would've saved me about 1.5 seconds. — atchius (msg) 23:35, 7 March 2007 (UTC)
[edit] 6.1 has 8 speakers ??
The description for 6.1 only consist of 7 speakers, but at the speaker placements, it stated 8 spekaers for all 6.1 system ? What is the extra speaker ?
ThinkVISION —The preceding unsigned comment was added by 205.210.223.129 (talk) 19:51, 3 April 2007 (UTC).
