Just when you think they're all done adding more channels to sound systems, they add a couple more. The June 18 premiere of Toy Story 3 also marked the premiere of Dolby Surround 7.1, a technology that allows a commercial cinema to add two additional channels of sound to the 5.1 channels they already have. The existing left, center, right, left surround, right surround, and low-frequency effects channels have been augmented with left back surround and right back surround channels. Dolby Surround 7.1's additional channels don't require any additional speakers, though-they employ the theater's existing array of back surround speakers.

According to Stuart Bowling, worldwide technical marketing manager for Dolby Laboratories, "Dolby Surround 7.1 provides four discrete surround zones, allowing the mixer to uniquely place audio with more definition and improve directionality in panning through 360 degrees around the theater. It allows mixers to add more definition to both 2D and 3D content, and raises the experience of 3D viewing by allowing the mixer to place sounds discretely that tie in with the 3D visuals."

As any home theater enthusiast can tell you, this development brings commercial cinemas up to the standard of the best home theaters, which already enjoy 7.1 through the Dolby TrueHD and DTS-HD Master Audio technologies available on Blu-ray Disc.

Unlike many past theater sound system upgrades, Dolby Surround 7.1 doesn't require herculean effort on the part of the theater owner. In fact, it's easier and cheaper than most home theater upgrades. "For theaters that are currently wired for Dolby Digital Surround EX, the transition to 7.1 is a simple one that can be accomplished with a software upgrade and a $100 audio cable," Bowling said. As of July 15, 938 theaters worldwide had already converted to Dolby Surround 7.1.