I had rearranged the seating for our home theater. My home theater system includes a 120-inch screen, a Panasonic AE3000 rear projector, five B&W 600 series speakers (1 center, 2 tower, 2 surround), an SVSound PB-13 Ulta subwoofer. The system is powered by a top-of-the-line Pioneer Elite AV receiver and a Sony Blu-Ray player.
The environment is not operating in a specially constructed room although it is located in a very large area — roughly 1,200 square feet with 9-foot ceiling. With such a large space, the acoustics are fine and the overall experience is just a lot of fun. We rarely head out to the cineplex.
When the seating was changed, I thought I should check the speaker placement. It was in rather poor shape for some reason. I am usually quite obsessive about placement and alignment and I remain perplexed as to what happened.
The optimum configuration for surround sound speaker arrangement is pictured below. The front speakers should be equidistant to the prime listening position. And the rear surrounds should be slightly behind the prime listening area. When I took the measurements, the center speaker was not in the center of the screen. The left speaker was 8 inches off the line from the right speaker — in other words the left speaker was 8 inches closer to the prime listening position. The center speaker was 11 inches forward of the right speaker. The right surround speaker was 17 inches closer to the prime listening position. All of the distance settings programmed into the receiver were incorrect. All of them.
The literature will tell you that minor variances in distance will impact the listening experience. My son helped me measure and tweak the room. I auditioned the room before and after and the difference in the soundstage was significant. I suppose my greatest surprise was that I had tolerated the listening environment with the assumption that everything had been tuned. And it had. As the speakers are freestanding, they must have been moved. By someone.
I am looking for them so watch out.
More information on speaker placement can be found here.