If you want standard 7.1 surround sound go with 7.1"A". You can also look at Dolby's website or Audyssey's website or even THX's website (the 7.1 for Dolby TrueHD and DTS HD MA).
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7.1 speaker configurations: which one to use?
I'm looking for input and recommendations for the best way to configure a 7.1 home theatre setup. I've noticed that the manual for the DTS encoder suite specifies two commonly used 7.1 configurations (along with five rare ones):
7.1 "A"
7.1 "B"
I'm not sure which one to use for my room configuration. Intuitively, the layout I'm calling 7.1 B would seem to be ideal from a backwards compatibility perspective.
With 6.1 material, I am assuming there is a 1:1 mapping of all channels save for Cs which I am assuming the AV receiver will map to both Lsr and Rsr, reproducing a mono rear channel in both rear speakers.
With 5.1 material, one presumably has the option of either using a 1:1 mapping and letting the Lsr and Rsr speakers fall silent, or using Pro Logic IIx or DTS Neo to produce a centre rear channel that is reproduced in the rear speakers. Presumably the former option is preferably for content that the mixing engineer intended to be 5.1, and the later for content that was designed to have a matrixed rear centre channel - eg. DD EX and DTS ES matrix.
It would seem to me that the 7.1A configuration, which lacks an Ls and Rs, would not have ideal speaker locations for directing the Ls and Rs of legacy 5.1 and 6.1 material.
However, what I am not sure about is which of the two 7.1 configurations are typically used on Blu-Ray discs. Is one predominant over the other? Is the user expected to reposition his Ls/Rs speakers to the Lss/Rss position for some films? Or perhaps I am misunderstanding something here? Have people had more success using one configuration over the other?
Thanks,
Steven
7.1 "A"
7.1 "B"
I'm not sure which one to use for my room configuration. Intuitively, the layout I'm calling 7.1 B would seem to be ideal from a backwards compatibility perspective.
With 6.1 material, I am assuming there is a 1:1 mapping of all channels save for Cs which I am assuming the AV receiver will map to both Lsr and Rsr, reproducing a mono rear channel in both rear speakers.
With 5.1 material, one presumably has the option of either using a 1:1 mapping and letting the Lsr and Rsr speakers fall silent, or using Pro Logic IIx or DTS Neo to produce a centre rear channel that is reproduced in the rear speakers. Presumably the former option is preferably for content that the mixing engineer intended to be 5.1, and the later for content that was designed to have a matrixed rear centre channel - eg. DD EX and DTS ES matrix.
It would seem to me that the 7.1A configuration, which lacks an Ls and Rs, would not have ideal speaker locations for directing the Ls and Rs of legacy 5.1 and 6.1 material.
However, what I am not sure about is which of the two 7.1 configurations are typically used on Blu-Ray discs. Is one predominant over the other? Is the user expected to reposition his Ls/Rs speakers to the Lss/Rss position for some films? Or perhaps I am misunderstanding something here? Have people had more success using one configuration over the other?
Thanks,
Steven
1 - 17 of 17 Posts
So is 7.1 B rarely used? Is there a way to tell which of the two is used on a particular Blu-Ray?
"A" is how the 7.1 blu-rays are recorded/mixed...... All 7.1 is, is 5.1 plus 2 surround back speakers. 5.1 you have the front 3 and then "side" surrounds, which are to be placed on the side walls between 90 and 110 degrees to the listener, so either directly to your side or slightly behind but still to your side. The surround back speakers in 7.1 then get added to that 5.1 layout. The surround back speakers should be on rear wall spread apart as to make a 60 degree angle to the back of your head or at least spread 4 feet apart. Surround back speakers should be placed a minimum of 3 feet behind the main listening position (MLP).
I would definitely go for layout "A", which will deliver better side-vs-rear separation in the surround field, at least compared to layout "B", which has all four surround speakers behind the listening position (waste of resources).
Ok, thanks a lot for the advice. I wonder why DTS offers both configurations?
An appropriately capable DTS-HDMA decoder can supposedly remap any 6.1|7.1 DTS-HDMA encoded BD audio track (which always identifies the authored|mixed speaker configuration used) into the specific 6.1|7.1 speaker configurations supported by the AVR. Except for the Cambridge Azur 651R|751R (and perhaps a few other high end AVRs) you are stuck with whichever 7.1 speaker layout ID the AVR manufacturer loaded into firmware. The Azur lets you choose which of two 7.1 layouts is closer to your actual installed speaker configuration, so that it can more correctly remap the soundtrack from a disk authored in 6.1 or "the other" 7.1 speaker configuration.
Given the lack of accuracy in speaker placement and room treatment believed to exist in the vast majority of 7.1 layouts, the absence of this setup parameter on most AVRs is understandable . . . and no AVR I've seen offers a similar setup option for TrueHD.
DTS expertise with remapping technology will presumably play a key part in the DTS-UHD "system" about which we will (supposedly) hear more in 2014.Q2, as the DTS press release about DTS-UHD (link) contains the statement:
Quote:
Originally Posted by sjblakey314 /t/1518739/7-1-speaker-configurations-which-one-to-use#post_24389769
Ok, thanks a lot for the advice. I wonder why DTS offers both configurations?
An appropriately capable DTS-HDMA decoder can supposedly remap any 6.1|7.1 DTS-HDMA encoded BD audio track (which always identifies the authored|mixed speaker configuration used) into the specific 6.1|7.1 speaker configurations supported by the AVR. Except for the Cambridge Azur 651R|751R (and perhaps a few other high end AVRs) you are stuck with whichever 7.1 speaker layout ID the AVR manufacturer loaded into firmware. The Azur lets you choose which of two 7.1 layouts is closer to your actual installed speaker configuration, so that it can more correctly remap the soundtrack from a disk authored in 6.1 or "the other" 7.1 speaker configuration.
Given the lack of accuracy in speaker placement and room treatment believed to exist in the vast majority of 7.1 layouts, the absence of this setup parameter on most AVRs is understandable . . . and no AVR I've seen offers a similar setup option for TrueHD.
DTS expertise with remapping technology will presumably play a key part in the DTS-UHD "system" about which we will (supposedly) hear more in 2014.Q2, as the DTS press release about DTS-UHD (link) contains the statement:
_Quote:
"Customized rendering designed for arbitrary speaker layouts enables consumers to adapt their AV system to their own home environment rather than pre-determined speaker layouts "
Very interesting. Thanks for the info. DTS-UHD sounds like a home theatre counterpart to Dolby's Atmos, in that it is object-oriented and not channel-oriented.
Keep in mind that these technologies are hybrid: channels AND objects. For example, Atmos has a 9-channel bed (3 fronts, 2 sides, 2 rears, 2 heights). Objects are in addition to those channels. The recording engineer can decide whether a certain piece of dialogue or music or effects should be mixed into channels or put on the Atmos bus as an object.Quote:
Originally Posted by sjblakey314 /t/1518739/7-1-speaker-configurations-which-one-to-use#post_24403022
DTS-UHD sounds like a home theatre counterpart to Dolby's Atmos, in that it is object-oriented and not channel-oriented.
The concept of remapping brings up an interesting question - if I were to go with a 5.1 system (and buy better but fewer speakers), what would I get when playing back a 7.1 Blu-Ray?
Does the receiver:
(a) perform a real-time down mix, eg.: [Lss + Lsr] + [Rss+Rsr] --> [ Ls + Rs],
(b) simply omit the rears (or Cr in the case of 6.1),
(c) give me the lossy Ls/Rs channels from the 1.5 mbps DTS core - which are presumably pre-mixed at the studio to contain both side and rear information,
(d) or something else entirely?
Does the receiver:
(a) perform a real-time down mix, eg.: [Lss + Lsr] + [Rss+Rsr] --> [ Ls + Rs],
(b) simply omit the rears (or Cr in the case of 6.1),
(c) give me the lossy Ls/Rs channels from the 1.5 mbps DTS core - which are presumably pre-mixed at the studio to contain both side and rear information,
(d) or something else entirely?
For movies both are good with a slight advantage for 7.1A.
If you are into surround music 7.1B is the better option.
If you are into surround music 7.1B is the better option.
Frank, your point about surround music is a good one. With 7.1A, it would mean that the surround channels from DVD/SACD/DTS CD, etc. would become side channels, and I'm not sure that's what the mixing engineers intended. This would seem particularly true for surround material sourced from 70's-era quad masters. For example, I'm guessing that when he mixed the quad version of Dark Side of the Moon, Alan Parsons was assuming that the listener would have two speakers behind his/her head, not at +/-90 degrees.
Both DTS-HDMA and Dolby TrueHD soundtracks contain metadata defining mixdown algorithms (7.1 => 5.1 => 2.0) for playback on a system with fewer channels than are contained in the soundtrack. Beyond that, the decoder may also fake a 7.1 speaker EDID--and thereby obtain channel info not nominally needed for 5.1 playback--in order to perform, e.g., 'exotic' post-processing before a final mixdown to 5.1|2.0 for playback..
So I guess the correct answer is "Hard to tell..."
_
So I guess the correct answer is "Hard to tell..."
_
No modern receiver should be doing (b) or (c). None of the sound should be discarded when downmixing, nor should the soundtrack go from lossless to lossy.Quote:
Originally Posted by sjblakey314 /t/1518739/7-1-speaker-configurations-which-one-to-use#post_24407631
(b) simply omit the rears (or Cr in the case of 6.1),
(c) give me the lossy Ls/Rs channels from the 1.5 mbps DTS core - which are presumably pre-mixed at the studio to contain both side and rear information,
I think some of you need to spend more time at the web sites of people who make the formats:
http://www.dolby.com/us/en/consumer/setup/connection-guide/home-theater-speaker-guide/index.html?utm_campaign=ce-ht&utm_medium=multi&utm_source=multi&utm_content=ce-ht-sym-speakersetup
Dolby recommends that the surround speakers are placed at 90-110°, or in other words, either directly to the sides or slightly back. THX gives the same recommendation for the surround speakers:
http://www.thx.com/consumer/home-entertainment/home-theater/surround-sound-speaker-set-up/
In other words, something that looks very much like the OP's 7.1 "A" or 7.1 "B" is fine. Since that is, according to the OP, the dts recommendation, we have universal agreement from the experts on surround sound, that either way is fine.
I think some of you need to spend more time at the web sites of people who make the formats:
http://www.dolby.com/us/en/consumer/setup/connection-guide/home-theater-speaker-guide/index.html?utm_campaign=ce-ht&utm_medium=multi&utm_source=multi&utm_content=ce-ht-sym-speakersetup
Dolby recommends that the surround speakers are placed at 90-110°, or in other words, either directly to the sides or slightly back. THX gives the same recommendation for the surround speakers:
http://www.thx.com/consumer/home-entertainment/home-theater/surround-sound-speaker-set-up/
In other words, something that looks very much like the OP's 7.1 "A" or 7.1 "B" is fine. Since that is, according to the OP, the dts recommendation, we have universal agreement from the experts on surround sound, that either way is fine.
Actually my original post was prompted, in part, by the fact that DTS doesn't seem to make a clear recommendation as far as 7.1 configurations are concerned. The manual for the DTS encoder suite indicates that both A and B encoding configurations are common (with an additional 5, which appear to be 5.1 configs augmented with overhead/height channels, that are uncommon), and it does not make a recommendation for which of these common options a mastering engineer should prefer. This led me to wonder which option is typically employed on blu-ray discs. I just want my setup to be as close as possible to what is intended by those who offer the discs, while maintaining backward comparability with 5.1, 6.1, 4.0 content.
Quote:
Originally Posted by Jack D Ripper /t/1518739/7-1-speaker-configurations-which-one-to-use#post_24409360
In other words, something that looks very much like the OP's 7.1 "A" or 7.1 "B" is fine. Since that is, according to the OP, the dts recommendation, we have universal agreement from the experts on surround sound, that either way is fine.
Actually my original post was prompted, in part, by the fact that DTS doesn't seem to make a clear recommendation as far as 7.1 configurations are concerned. The manual for the DTS encoder suite indicates that both A and B encoding configurations are common (with an additional 5, which appear to be 5.1 configs augmented with overhead/height channels, that are uncommon), and it does not make a recommendation for which of these common options a mastering engineer should prefer. This led me to wonder which option is typically employed on blu-ray discs. I just want my setup to be as close as possible to what is intended by those who offer the discs, while maintaining backward comparability with 5.1, 6.1, 4.0 content.
Their recommendation allows for some leeway in the placement of the surround channels. There is no standard for absolute precision in their placement. So you will never find such a standard. Of course, individuals can make up whatever story they want and claim it, but the reality is, the surround channels do not have a rigidly defined spot where they are supposed to be. If you look at the Dolby site, you will see that there is leeway in the front speakers as well. The idea that everything is done with absolute precision is simply false, and you will likely find that different mixing studios use different configurations. Think about it: It is a pretty absurd idea to suppose that every mixing studio places all of the speakers at precisely the same angle relative to the listening position.
The formats allow for some variation, and anything within the range of acceptable positions is correct. It is only if one strays from the guidelines that it can be incorrect.
If this lack of precision upsets you, think about the fact that different mixing studios use different speakers, each with their own unique characteristics, and yet they EQ and mix based on their particular speakers in their particular room. The whole thing, from start to finish, is filled with imprecision. But given what most people do to it when they get it in their homes, the lack of precision in the mastering is generally a minor consideration. At least, as long as it was mastered in accordance with the imprecise standards.
Quote:
Originally Posted by sjblakey314 /t/1518739/7-1-speaker-configurations-which-one-to-use/0_100#post_24412533
Quote:
Originally Posted by Jack D Ripper /t/1518739/7-1-speaker-configurations-which-one-to-use#post_24409360
In other words, something that looks very much like the OP's 7.1 "A" or 7.1 "B" is fine. Since that is, according to the OP, the dts recommendation, we have universal agreement from the experts on surround sound, that either way is fine.
Actually my original post was prompted, in part, by the fact that DTS doesn't seem to make a clear recommendation as far as 7.1 configurations are concerned. The manual for the DTS encoder suite indicates that both A and B encoding configurations are common (with an additional 5, which appear to be 5.1 configs augmented with overhead/height channels, that are uncommon), and it does not make a recommendation for which of these common options a mastering engineer should prefer. This led me to wonder which option is typically employed on blu-ray discs. I just want my setup to be as close as possible to what is intended by those who offer the discs, while maintaining backward comparability with 5.1, 6.1, 4.0 content.
Their recommendation allows for some leeway in the placement of the surround channels. There is no standard for absolute precision in their placement. So you will never find such a standard. Of course, individuals can make up whatever story they want and claim it, but the reality is, the surround channels do not have a rigidly defined spot where they are supposed to be. If you look at the Dolby site, you will see that there is leeway in the front speakers as well. The idea that everything is done with absolute precision is simply false, and you will likely find that different mixing studios use different configurations. Think about it: It is a pretty absurd idea to suppose that every mixing studio places all of the speakers at precisely the same angle relative to the listening position.
The formats allow for some variation, and anything within the range of acceptable positions is correct. It is only if one strays from the guidelines that it can be incorrect.
If this lack of precision upsets you, think about the fact that different mixing studios use different speakers, each with their own unique characteristics, and yet they EQ and mix based on their particular speakers in their particular room. The whole thing, from start to finish, is filled with imprecision. But given what most people do to it when they get it in their homes, the lack of precision in the mastering is generally a minor consideration. At least, as long as it was mastered in accordance with the imprecise standards.
1 - 17 of 17 Posts
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