Look for sound leveling, SRS TruVolume, to correct sound variationsA recent study says 93% of consumers are annoyed by fluctuating volume levels when switching from channel to channel and when programming goes into or out of commercials. Expect this problem to grow as we watch more content on internet-connected TVs like YouTube videos, notorious for wide swings in volume from video to video. I see you nodding. Voice levelers, a technology that currently must be built into a TV or sound system component, can solve this problem.

Dolby introduced its sound leveling technology in 2007. According to a Dolby representative, Dolby Volume is available in 26 products with eleven companies (Anthem, ARCAM, AudioControl, Bryston, Emotiva, Harman-Kardon, Integra, Onkyo, Sherwood and Parasound as well as HDTVs from Toshiba). Yes, only one TV manufacturer in the bunch.

Congress is also in the mix, currently reviewing The Commercial Advertisement Loudness Mitigation Act, also known affectionately as The C.A.L.M. Act. The proposed legislation would require the Federal Communications Commission to regulate the audio of commercials from being broadcast at louder volumes than the program they accompany. Well intentioned, but this bill only addresses commercials, leaving unwanted volume changes between programs or songs up to the consumer.

Now there s another player on the sound leveling field with a slightly more complex method of leveling sound: SRS Labs, an audio technology company headquartered in Santa Ana, California. Alan Kraemer, SRS Labs technology chief says leveling is surprisingly complicated and requires a sophisticated solution.

When done poorly, unnatural sound effects creep in, such as the sound of rain fading out when an actor talks, then coming back up when there s no other noise present. Over compression turns explosions into dull thuds.

The high-tech equalizing is done through an algorithm programmed into the device that puts all audio at the same reference level, so what you hear is consistent or leveled. The algorithm in the software shrinks the digital audio signal, so subtleties in the audio are preserved rather than distorted or deleted. No more loud commercials, but the program audio will sound as the director intended, and music will transition nicely from song to song.

Modern audio technology is based on psychoacoustics, the science of how we perceive and process sound. More than just a mechanical process of sound waves hitting the ear drum, hearing involves translating mechanical impressions into recognizable sounds, and it involves the loss of some sounds due to masking.

SRS TruVolume uses 20 frequency bands that model the human hearing mechanism, monitoring and adjusting the audio signal level continuously, resulting in a consistent volume, regardless of fluctuations in the audio source. Mirroring human hearing allows the software to accurately compress audio without disrupting the perceived sounds. With sound leveling, users set the volume once whether they re watching a movie or listening to music. No more wild grabs for the remote.

How do you get it? Today, you ll look for products that have this technology built into the hardware. Samsung and Vizio both offer HDTVs with an SRS TruVolume sound leveler. SRS TruVolume is also integrated into Vizio s HD Sound Bar with Wireless Subwoofer. Yes, that s a favorite I wrote about last month. $300 from Walmart.

 I believe all of our TVs should have SRS TruVolume going forward,  says VIZIO s Vice President and Co-Founder, Ken Lowe.  Properly calibrated and intelligently managed audio volume are what consumers expect when they watch TV. 

But what about viewers who use a receiver and separate speakers for sound or TVs without this technology? Sit tight. In a few months, SRS will introduce a small standalone box that does the same trick as the built-in feature. MyVolume will hook up to your cable box via HDMI. We re waiting on a firm price, but SRS has promised somewhere between $25 and $100. Another one for your holiday list.

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