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7.1 and 5.1 surround speakers names
Old 15th February 2020
  #1
Gear Nut
 

7.1 and 5.1 surround speakers names

Hello guys, I have a question with regards to 7.1 and 5.1 setups.
What are the numbers in 7.1 and 5.1 referring to?

I understand that in a 5.1 for example, we have front right, front left, rear right, rear left, but this is only four speakers.
What are the 5th and 6th speakers? I assume 5th is the subwoofer. Okay, what about the sixth?

How about the 7.1? Can someone explain to me in a really detailed way please?

Thanks

Sam
Old 15th February 2020
  #2
Lives for gear
 

do your homework and check relevant aes and/or dolby papers...
Old 15th February 2020
  #3
Gear Nut
 

Quote:
Originally Posted by deedeeyeah View Post
do your homework and check relevant aes and/or dolby papers...
I have done that already and didn’t perfectly understand it. Please explain if you can and if you cannot, then avoid posting such comments.
Old 15th February 2020
  #4
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iluvcapra's Avatar
Your confusion is understandable, the names are not systematic.

Usually the first number refers to the number of speakers on the horizontal plane around the listener. The second refers to the number of subwoofers. There is sometimes a third number these days which indicates the number of speakers above the listener.

If the first number is odd, that usually means there's a center channel. If the first number is even, you have to figure out from context where the speakers are but 2 is self-explanatory, 4 is probably LF/RF/LR/RR (though it might be LCRS). "6.1" usually means there's a center front and center rear channel (this is very rare and was only used on a few films, particularly with Surround-EX in the 1990s).

There are usually a max of three front speakers, so 5.1 means three front channels feeding usually three front speakers (L, C, and R) and 2 surround "channels," which will in fact either feed a big array of speakers around the listeners, OR just two speakers at points behind them. Which this is, and where these speakers are positioned, and the size of the array is dependent on context: is it home theater or big theater, IMAX or normal theater...

There are however certain historical formats where there were five screen channels, like Cinerama and SDDS. Another notation you sometimes see people use is three numbers separated by plus signs or slashes, like "3+2+1", and that indicates the number of screen channels, the number of surround channels, and the number of LFE channels. (There is also the question of wether the screen is curved or not, and thus the screen speaker array is curved.)

Same with 7.1, where there are now four channels in the surrounds which feed four arrays of speakers, again symmetrically arranged around and behind the listeners so there's an LSS (left surround side) and LSR (left surround rear).

The top channels are a whole other thing. So Dolby Atmos usually uses three numbers, like "7.1.2" or "9.1.4" to indicate how many horizon, LFE and overhead channels there are (either installed in a home theater, or in use in a bed element).

BUT, Auro 3D and the NHK immersive formats call themselves "11.1" and "22.2" though they have speakers above and in-line (and in NHK's case, below) the listener. Also in Atmos the top speakers are arranged in two (left and right) front-to-back arcs over the theater, and as the number of top channels goes up, you get more speakers on the arc; but NHK and Auro arrange their top speakers differently.

EDIT- Oh also don't forget Tom Holman's 10.2 system with two height channels, three screen channels and an additional mono surround amidst or directly under the audience. And stereo bass-managed sub+LFEs because TMH is a big bass management fan. Oh yeah, bass management...

And again, wether we're talking about individual speakers or an array fed by a single channel is contextual: in a home theater, the top channels will either be single speakers, or they'll be a diffused reflected image from top-firing speakers (or a sound bar) hitting the ceiling over the listener.

If you want to really get into it, you can read something like ITU BS.2051 which is an attempt to tame the menagerie, and it gets into questions like spherical versus cartesian coordinate systems for speaker placement, allocentric versus egocentric sound object positions, which are more important as we start to see more rendering-type systems in the home and on mobile devices. Did you know Samsung Galaxy 10s have an integrated Dolby Atmos renderer?

So in short, use headphones.

Last edited by iluvcapra; 15th February 2020 at 08:33 PM..
Old 15th February 2020
  #5
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TVPostSound's Avatar
Quote:
Originally Posted by iluvcapra View Post
So in short, use headphones.
Stereo or binaural?
Old 15th February 2020
  #6
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iluvcapra's Avatar
Quote:
Originally Posted by TVPostSound View Post
Stereo or binaural?
Pick one at random and surprise yourself

I was staring at my RMU monitor the other day and I hate all the dumb abbreviations for the channels, there should be something like a Whyte notation or UIC classifications for speaker formats and speaker channels that tells you at a glance what it is and what the speakers are.

Like L C R is pretty self-explanatory, but it takes some cogitation to remember what LRH and RSS and LW are...
Old 17th February 2020
  #7
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Quote:
Originally Posted by producerxtr View Post
I have done that already and didn’t perfectly understand it. Please explain if you can and if you cannot, then avoid posting such comments.
c'mon: fire up your daw an look how buses get labelled...

yes, there are many different ways how things can get/were done but most of this got streamlined/sorted out over the years so hardly anyone is using any unorthodox bus order or labelling anymore (other than l/c/r/lfe/ls/rs and the order/pairs being l/r, c/lfe, ls/rs).

if not, most gear can re-route channels - in case of doubt, stick either to aes (or dolby) recommendations, to what your gear offers as a default setting or ask your clients what they want/request!

here's a link to one of the many sources:

http://www.aes.org/technical/documents/AESTD1001.pdf
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