Surround Sound Speaker Placement and System Setup
Dolby vs ITU: The 5.1 & 7.1 Speaker Placement WarPART: 1 2 3 4
Which surround sound setup standard should you choose? Ah, the paradox of choice. There are several options floating around.
Most guidelines use the center of the listener’s head as the reference point for positioning the front speakers.
But studio designers tend to place this reference point slightly behind the listening position. This way your front left and right speakers are pointing at your ears instead of your brain.
Multichannel studio monitor placement for music mixing
Audio experts can’t seem to reach a consensus on 5.1 and 7.1 surround sound speaker placement. There are so many variables involved.
To make it easy for you, the ITU-R BS.775 standard (multichannel stereophonic sound system) is most common for multichannel music mixing and nearfield critical listening. It provides good localization throughout the surround sound stage.
For 5.1 speaker setup, ITU recommends the right surround (LS) and left surround (RS) speakers be placed between 100 and 120 degrees with respect to the center front monitor. 110 degrees is a good place to start.
Genelec also recommends the ITU standard when arranging their 8000 series studio monitors for 5.1 and 5.2 channel mixing.
So everyone agrees on ITU? Well, no…
The National Academy of Recording Arts and Sciences (NARAS), who host the Grammy Awards, recommend the side/rear studio monitors be placed from 110 to 150 degrees, with optimum range between 135 and 150 degrees.
Multichannel studio monitor placement standards are still in development because music-only surround sound formats have not been well standardized.
For control rooms with main monitoring systems, Phillip Newell addresses surround sound speaker and subwoofer placement in Chapter 21 of his book, Recording Studio Design. He also gives guidelines for selecting the best surround sound speakers and main monitors, and how to flush-mount them.
Newell concludes that for the highest quality monitoring, music-only control rooms would optimally have five full-range, flush-mounted main monitors, with no subwoofer!
But this advice only applies to well treated control rooms with relatively neutral acoustics. That means 5.0 surround sound control rooms should have very short decay times with excellent low frequency control (a tight now end).
For mix environments with suboptimal bass absorption, Newell recommends a single subwoofer, flush-mounted in the front wall (or placed close to the wall) to the left or right of the room’s center line.
5.1 and 7.1 speaker placement for surround sound home theater
For cinema and home theater, it’s a battle between ITU, THX and Dolby surround system standards.
For home theater 5.1, Dolby and THX suggest placing your LS and RS speakers 90 to 110 degrees from center. ITU recommends 100 to 120 degrees, which gives a wider spatial impression.
It boils down to personal preference. You can experiment with surround sound speaker placement to see what you like, and what creates the most realistic reproduction.
For a 7.1 surround sound system, your best bet is to use the recommendations by Floyd Toole in his book, Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms.
Floyd is a home theater sound guru, an expert in the field of sound reproduction, and the 2008 winner of the CEDIA Lifetime Achievement Award.
His suggestions are in line with Dolby 7.1 setup: side speakers placed 60 to 100 degrees from center, rear speakers placed 135 to 150 degrees (135 degrees is preferred).
The best surround sound system layout for your theater is the one that provides the most immersive cinematic experience. You want accurate localization and an enveloping sound stage that feels natural.
You should feel connected with your media.
Multiple subwoofer placement in your home theater
Subwoofer placement can be tricky, and finding the best position usually requires testing. I’m not going to go into the details in this tutorial, but here is something to consider if you have a home theater or multi-seat hi-fi listening room…
In home theaters you want consistent low frequency response at every seat, and to achieve this, multiple subwoofers (e.g., four) tend to be better than one.
You will need to apply some bass traps and acoustic panels to tame the key acoustical problems, but you can also use processed multiple subwoofers to give a more uniform bass response throughout your room.
For the low down see Floyd Toole’s book, Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms. And if you need help, hit me up for a room acoustics analysis.
Electronic room correction can’t fix the effects of strong early reflections, and that includes speaker boundary interference. But it’s actual possible to tame unwanted room modes using a system of multiple subwoofers, carefully placed, calibrated and equalized. Pretty cool stuff!
Floyd Toole introduced this in an article called ‘Adapting to Acoustic Anarchy in Small Spaces’ (Published in the Audio Engineering Society (AES) Journal).
Treat your room like a spoiled child
After you’ve placed your speakers, taming your acoustics means lavishing your room with attention and attire. There are two things left to do to get an incredible sound:
- Go nuts with acoustic treatment. For a simple way to get started, check out this bass trap placement tutorial. If you’re ready to get a bit more sophisticated with sculpting your sound, here’s the acoustic treatment layout guide.
- Nerd out with acoustic measurements to optimize your room treatment, speaker and subwoofer placement.
If you’re subscribed to email updates, I’ll send you tips for treating your room in the near future. So stay tuned!
PART: 1 2 3 4
|< Part 2: Speaker-Wall Distance||Part 4: Acoustic Treatment Layout >|
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by Tim Perry