Extended Surround Part Deux: Boldly Sticking with 5.1
Years ago, I experimented extensively with both 6.1- and 7.1-channel surround sound, both with a single surround back channel and with two surround back channels. I was then in a dual-purpose living room space, and the 6.1 with the single surround back channel was most effective, but not enough to totally sell me on the concept. My last two rooms have been dedicated media spaces, and each has been in the neighborhood of 25x16, with a first a 10’ ceiling and now just under 9’. The first house was new construction with a ground-up media room build. It was a big room, and I pre-wired the back wall for 7.1 as a precaution. It turned out I never felt I needed it and when I moved to my current house, a retrofit job, I didn’t give any consideration to 7.1, let alone height and width expansion. Let me speculate on why.
Each of these two large spaces has allowed optimal placement of my 5.1-channel system, and the speakers and components I’ve chosen maximize imaging. My reference speakers for years have been time- and phase-coherent models from Vandersteen audio. Placement roughly conforms to the ITU surround speaker placement recommendations, which call for the left and right speakers equidistant from each other and the main listening position (a 60 degree triangle between the two speakers and listener, although my speakers image best a little closer together than that and are places loser to 50 degrees off center) and surrounds at 110 degrees, which is just behind the main listening position, and in my case elevated above ear level. The left and right surrounds are each equidistant to the listening position, and very close to the distance from left and right speakers to the listening position. There’s no asymmetry to deal with at any speaker position.
These speakers put up an immense but intimately focused 360 degree soundstage. When I listen to 7.1-channel soundtracks with information mixed to the back surround, I get a dead-on phantom image behind me that’s immensely convincing. More convincing, in my opinion, than dedicated speakers in the rear of the room provide. In addition, I don’t use out-of-phase dipoles for surrounds, as some people do, and there is seamless sidewall imaging between the surround and front positions, well beyond the physical speaker, without the addition of width speakers. And the sensation of height I get in any soundtrack that conveys it is remarkable. My room is a daylight basement below the main floor and if you put on Master and Commander the sensation of people walking above decks is so overwhelming it sounds like people are walking in our kitchen above. It’s indistinguishable from the real thing, as are the height sensations from rainstorms and claps of rolling thunder when they’re rendered with veracity on the soundtrack. Honestly, I’ve heard nothing to convince me that in my room I’d hear anything more convincing than what I already have. Height, width, back surround: check, check and check, I’ve got it all.
However, a few things need to be acknowledged. Not everyone has an optimized dedicated space. For instance, for people with long rooms in which the traditional surrounds would be in front of some listening positions, 7.1 is probably a must to get the best from even 5.1-channel surround. There are many other situations and rooms that might make 7.1 and beyond a better choice. In addition, there are myriad other speaker setup compromises and asymmetry issues that can hinder imaging. More speaker positions being accommodated in room can solve issues like this. I’m simply fortunate enough not to have to pursue them.
And there’s personal taste and preference. This is a hobby called home theater, it’s not curing cancer. There are many paths to home theater bliss, and the thing I admire so much reading here is the willingness to try and experiment with new technologies. Such a hobbyist approach from readers is something common in the two-channel audio world, and it’s something I’m very pleased to find alive and kicking here on the home theater side of things. So, keep it up! And keep telling me what you’re up to.