Dolby Launches Loudness Controller

At CES2007 this week, Dolby announced a new audio processing technology it hopes will help solve a problem that has vexed consumers for years--loudness.

Dolby Volume approaches the discrepancies in volume levels by modeling how humans perceive audio to finally eliminate variable loudness when changing channels or programs, without disruptive audio artifacts. The company says it also delivers a robust and vibrant audio experience by dynamically compensating for the human ear's lower sensitivity to bass and treble sounds as the volume level decreases. These adjustments are automatic and do not require user intervention as the volume changes.

Rocky Graham, director of broadcast products for the San Francisco-based audio company says Dolby Volume addresses the myriad non-Dolby Digital signals coming in to today's consumer receivers.

"The loudness problems that consumer face are very complex," Graham said. "There's more and more different types of signals coming from different sources."

Broadcasters have been required to use dialnorm to control the volume in digital audio signals for the past decade but there has been some question as to how many have actually implemented the parameters. Dolby Volume does not let broadcasters off the hook; they still need to implement dialnorm as well as include metadata in the audio signal, according to Graham.

"The broadcasters still need to be aware of metadata and take the same care in measuring and setting dialnorm," Graham says. "[Dolby Volume] doesn't change very much in terms of what the professional side will be doing."

Graham says that when dialnorm is set correctly, Dolby Volume will do very little. A major benefit for Dolby Volume is to handle those signals that don't contain dialnorm or metadata to address loudness, such as DBS, which uses MPEG audio on non HD-signals, or gaming, for example.

"Dolby Digital already contains the capability for broadcasters to control loudness through dialnorm parameters," he said. "There's no change necessary there. If dialnorm is set correctly, that's the best way to assure that you get the well-matched signal and the highest quality signal. This not a replacement for dialnorm. Many audio sources do not have dialnorm or any metadata at all."

Dolby Volume will be available to integrated circuit manufacturers in Q1 of 2007.