Digital Cinema Report has an excellent analysis of the reasons and technology of Dolby’s new 7.1 Audio system. There is no need for a pull-quote as it is all good. Read it at:

A Sound Idea

Bloomberg has a good article as well:
Pixar Gets Dolby to Invent ‘Rain of Sound’ to Match 3-D Movies
excerpt:

The current setup in most theaters, known as 5.1, couldn’t direct sounds precisely enough to specific parts of the theater, says Paul Cichocki, post-production supervisor at Pixar. The audio didn’t feel like it was putting the viewer in the middle of the action, he says.

“We really wanted to take sound to the next level, and we just weren’t able to do much in 5.1,” Cichocki said. “If we could put sound in the right places, it helps your brain look in the right place.”

That’s why Pixar urged Dolby Laboratories Inc. to develop a new version of its sound system, the dominant audio technology in theaters. The resulting Dolby Surround 7.1 standard lets movies deliver sounds through seven speakers, plus one subwoofer, which handles bass. For Dolby, the technology helps the company keep pace with other cinema improvements — from crisper digital images to reclining seats — and give audiences a reason to keep coming back.