7.1 Placement and Acoustics
Aug 12, 2010 12:28 PM, By Dan Daley
The release of 8-channel audio creates an expanded home theater soundscape with more opportunity and possibly more confusion.
7.1 in the Home
Installers need to acknowledge how much more important a role acoustics play in the 7.1 era. Acoustician John Storyk, principal in Walters-Storyk Design Group—which recently formalized its home theater design operations with the acquisition of Maxicom, a Miami systems integration company—says in addition to choosing treatment materials for absorption, reflection, and diffusion, theater installers should also consider loudspeaker types when it comes to 7.1. “I recently did a theater with a 7.1 system in which there was a sizable seating area available, but the client wanted to use it as a very private screening/listening space, so there’s literally one seat,” he says. “You would normally choose a dipole-type speaker for the sidewall surrounds as they would give you wider, more consistent coverage. But in this case, a direct-radiating speaker was called for to permit more precise aiming of the side surrounds.
“You could still use a dipole speaker, if you prefer, but that kind of solution could in some cases take those speakers below the recommended delay times. Then you’d need to add more diffusion. That’s why we believe that the acoustical part and the systems aspect of a theater design should come from the same mindset, or at least that the acoustical aspect needs to be considered in the earliest stages of the theater’s design. Those processes need to be integrated.”
If 7.1 does anything, it’s that it encroaches on more and more residential real estate. That’s less of a problem in say, Dallas, as it might be in Manhattan, where interior dimensions are often measured in inches instead of feet. Michael Goodrich, president of Spectra Audio Design Group in Manhattan, says even in the upper end of the condo market, space in the city is always at a premium. In open floor plans or where living rooms and dining rooms flow through to each other, he’s found that he can squeeze a proper 7.1 system in if he can find what he needs behind the walls.
“You can’t put a ceiling speaker in most condos because there are slabs in between floors,” he says. “But as long as you use an in-wall speaker with an integrated back box, like the Triads, you can use those as natural attenuators to keep sound from bleeding into the adjacent residential units and putting the client in jeopardy of breaking condo or co-op board rules. In fact, I prefer to use in-wall for the L-C-R array, as well.”
Home theater surround in 7.1 will do for loudspeaker manufacturers what 5.1 did, only more so: make them really, really happy. “There’s nothing wrong with selling more speakers,” says Will Eggleston, marketing director for Genelec, without a trace of irony. But he makes an interesting point that goes to the heart of 7.1’s sidewall loudspeakers: “Where exactly they should be positioned is really a matter of what the [film sound] mixer’s intentions are,” he says. While Hollywood is still working out its own best practices regarding the use of the 7.1 format, certain generalities have emerged. Eggleston says that the side channels are essentially discrete extensions of the surrounds rather than of the L-C-R array, and bridging the gap between the front and rear loudspeakers will foster the immersiveness that film sound mixers prize. Thus, placement should be lateral to the viewer. If that’s the case, it also argues for employing smaller loudspeakers that won’t require full-bandwidth response capability.
There are already home theater enthusiasts who are eyeing the 9.1/9.2 format, adding an overhead component to the soundscape. CEDIA’s Dave Pedigo says there might be some pushback against this relentless proliferation of audio channels at some point. Then again, he says, it’s an opportunity for more personalization of a home system. He likes to turn off the center channel while watching sports broadcasts. Once you can’t hear the announcers, he says, “it’s like actually being at the game.”
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