Dolby Cites Dolby-Volume Progress

New York — Dolby Volume sound-leveling technology is closer to appearing in DTVs and A/V receivers (AVR) to make it possible for consumers to apply one preset listening level to all sources and programs played back through a home entertainment system.

Dolby contends its technology doesn’t suffer from audio “pumping” or other sonic artifacts introduced by other volume-control technologies, such as automatic gain control and compression.

For DTV marketers, Cirrus Logic has begun volume production of the first audio DSP processor to incorporate Dolby Volume code specifically for use in DTVs. The chip, a two-channel processor, will be demonstrated in a DTV set of unspecified brand at Dolby’s International CES display in January. TV sets with the chip could appear in U.S. stores later this year or early next if adopted by TV makers, a spokeswoman said.

For the A/V receiver marketers, Dolby plans to team with an unspecified audio supplier at CES to demonstrate a working engineering-sample of an AV receiver with its technology. The first AVRs with Dolby Volume could appear in stores as soon as the fall, Dolby said.

In a TV, the audio processing technology maintains a consistent perceived volume level when channels are changed, a TV program transitions to a commercial, a TV’s video inputs are switched and when a broadcast source is switched from analog to digital.

Dolby Volume also dynamically and automatically compensates for the human ear’s lower sensitivity to bass and treble sounds as volume levels decrease. The technology uses up to 40 bands of parametric equalization, with boosts or cuts up to 30dB, to ensure that low- and high-frequency sounds, particularly ambient background sounds, are audible when a program’s volume is lowered automatically to maintain a user’s preset listening level.

“We reverse the Fletcher-Munson curve,” a spokesman noted, explaining that the human ear’s perception of low and high frequencies drops off faster with declining volume than the perception of midrange sounds.

“We preserve audio quality while eliminating the level differences,” another spokesman added.

In an AVR, Dolby Volume’s benefits would be applied to as many as six channels in a surround system, and the benefits would extend to content from connected TVs that lack Dolby Volume. The AVR would also maintain a set volume level when switching between video sources, such as from TV to DVD, and when switching between audio sources, including outboard satellite radio tuner, HD-Radio tuner or iPod.

In a multichannel application Dolby Volume is applied to each channel based upon the specific needs of that channel, a spokesman said. The effect will “obviously be more noticeable when you are listening in a multichannel environment where the perceptual loss of low and high frequencies, and emphasis on midrange, contribute to a perceived loss of soundfield ambience,” he explained.

Dolby didn’t say whose chip would be embedded in the AVR that would be demonstrated at CES, but Cirrus Logic did say that it plans additional Dolby Volume-equipped audio DSPs for a “wide variety of consumer electronics products,” including AVRs, home theater in a box (HTiB) systems, and stereo audio systems.