Dolby Atmos, the advanced theater sound system, is expanding into more theaters in the U.S.

Regal Cinemas announced this morning that it has installed Atmos in 20 of its Regal Premium Experience (RPX) screens. Those Atmos screens are available for the start of the run of Warner’s Superman reboot, “Man of Steel.”

The “object-oriented” Atmos system starts the equivalent of 128 channels and automatically mixes them down to the number of speakers installed in a theater. Full Dolby Atmos installations like the RPX have dozens of full-tonal-range speakers on the walls and ceiling of the theater, which allows sound to be placed very precisely in space — especially important in pictures shown in 3D, like “Man of Steel.”

Atmos is competing with Barco’s own advanced theater sound system, Auro 11.1 3D, which uses fewer speakers and is less expensive to install. Dolby’s longtime rival, DTS, has its own object-oriented system, MultiDimensional Audio (MDA).

The news of the Regal deployment of Atmos comes on the heels of announcements that Wanda Cinemaline Corp. in China and SPI Cinemas in India will also install Dolby Atmos at some locations.