Dolby, DTS Add Height To Surround Sound

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Las Vegas – Dolby and DTS attended CES and demonstrated separate post-processing matrix-decoding technologies that derive height information from two-, 5.1-, and 7.1-channel soundtracks for playback through two front-height speakers.

Dolby is also targeting game developers to encode matrix height information into their surround-sound mixes, said Craig Eggers, Dolby’s senior manager for CE partner marketing. “We could do it in music and movie mixes, too,” he added.

Adding a vertical component to horizontal soundfields adds more realism and airiness to movie soundtracks and games, the companies contend. The technologies would elevate the sounds of hovering helicopters in games and movies, and in music videos, add more “depth, dimension and presence,” said Eggers. Rain would seem to be falling on a listener’s roof. Planes flying overhead will actually sound as if they’re flying overhead rather than through a listener sitting on the couch, said DTS marketing VP Tom Dixon.

Incorporating height information in a surround mix would enable game developers to incorporate height effects that would more precisely track visual game play than post-processing would, Dolby’s Eggers noted. DTS, however, has no plans for now to market its technology for encoding in games and other source material, said spokesman Anthony Watkins.

Dolby’s technology is Dolby Pro Logic IIz, which adds two front height channels to typical 5.1- and 7.1-channel home theater configurations to create surround systems with up to 9.1 channels. Dolby’s Eggers said IIz-equipped AV receivers will be available “very soon,” with the first arriving before CEDIA. At the show, Dolby displayed a prototype Dolby Pro Logic IIz 7.1-channel AV receiver from Onkyo.

For its part, DTS demonstrated a new technology that adds two front height and two additional horizontal-plane surround channels to create a soundfield with up to 11.1 channels. The technology, in the Neo family but as yet unnamed, can also be used to create only the two height channels. “The algorithm is ready,” and the first AVRs with the technology could appear late this year or early next, said DTS’s Dixon.

Dolby chose to focus on front-height channels rather than add additional surround channels or back-height channels because “it’s easier to localize sounds in front of you,” Eggers claimed.

Both technologies could be incorporated into chips already used in low- to high-priced AVRs, both companies said. “MIPs are not an issue these days,” DTS’s Dixon said. “If a receiver has [losslessly compressed] DTS HD Master, it can do Neo X.” During CES, an AVR with DTS HD Master and Dolby TrueHD was announced by Pioneer at a suggested $299.

Many existing AVRs and home theater preamp processors already incorporate enough amplifier channels to support the technologies, both companies noted. Nine-channel AVRs often use four amplifier channels to biamplify the front left-right speakers or to drive two speaker pairs in a multiroom application. Two of those amps could be redirected to drive a pair of height speakers in a system with seven horizontal-plane channels, Dolby said. Denon offers a 9.3-channel home theater preamp processor, and Pioneer offers a 10-channel AVR. Yamaha’s flagship 11-channel AVR already supports two front height and two rear height channels using proprietary Yamaha technology.

To add height channels, the Dolby and DTS technologies identify nondirectional decorrelated sounds in the surround mix process them as left- and right-height channels. DTS’s version also adds some correlated directional information to the height channels, said senior R&D VP Paul Smith.

In an 11.1-channel DTS setup, the left and right height speakers would be placed above the left and right main speakers. The distance between a height speaker and main speaker would be the same as the distance between the main speaker and center-channel speaker, said Smith. The six surround speakers would be arrayed like this: On the right, one speaker would be placed at 90 degrees from the listener, with another at 120 degrees and the third at 150 degrees. The left-side surrounds would be likewise positioned.


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