Given that TV makers can already choose from at least two
volume-leveling technologies— Audyssey Dynamic Volume and Dolby Volume—the announcement
that SRS has launched a competing technology might be greeted with the same
excitement as a new brand of HDMI cable. According to SRS chief technology
officer Alan Kraemer, though, SRS’s TruVolume technology has a big advantage
over its competitors … and his pitch is not the usual “we’re better” spiel.
Technologies such as TruVolume seek to solve the
decades-old problem of loud commercials blaring out at double the volume of the
TV show you’re watching. In the past, manufacturers have tried to quash such
outbursts using primitive automatic level circuits, but in Kraemer’s words, “Those
either did nothing or really messed up the sound.”
Like its competitors, TruVolume employs the science of
psychoacoustics to keep the volume at a cozy level. “For example, you don’t
perceive a 20-decibel shift in loudness at low frequencies as much as you
perceive it in the midband,” Kraemer explained. SRS used this knowledge to
shape TruVolume. To prevent the annoying “breathing” or “pumping” of background
noise that an automatic level control can cause, TruVolume continuously
analyzes 20 frequency bands, and applies different levels of gain control to
each band. Its effects are more extreme in the midrange, and subtler in the
bass and treble.
says other types of material can profit from having TruSurround watch over
their gain. “If you’re using a streaming service like Pandora or YouTube, where
sound is coming from a lot of different sources, the volume can really jump all
over the place. TruVolume keeps it all at a comfortable level,” he said.
TruVolume and its competitors (mainly that “Dolby is less aggressive in
controlling volume jumps”), but his frequent use of the pronoun “we” to refer
to Audyssey, Dolby, and SRS as a group showed how softly he’s beating that drum. He did point out one advantage, though, that might make TruVolume far more
ubiquitous: It’s less expensive to add to a product.
“TruVolume consumes about half the MIPS of Dolby Volume,”
he stated. By MIPS, he was referring to the “millions of instructions per
second” that a digital signal processing chip inside a TV is required to
execute. The more MIPS a technology uses, the more powerful (and expensive) a
DSP chip it requires. “Our whole thing is to chew up fewer MIPS and accomplish
the same thing or more,” he noted. “A relatively inexpensive DSP chip can
implement this. Cirrus Logic has also created a drop-in TruVolume module with analog
input and output that manufacturers can add to products that don’t have DSP
chips.”
might put it: You're not gonna pay a lot for this muffler.
also made its way into several new Samsung and Vizio TVs. (According to SRS, the technology behind TruVolume was originally called Volume IQ and was announced in January 2008.) Kraemer said SRS had
just signed a major manufacturer of set-top boxes as a TruVolume licensee, but
wouldn’t reveal the company’s name.
into more standalone audio products, Kraemer said the real potential beyond the TV market lies in iPhones and BlackBerrys. “We’ve created a variant of TruVolume called MaxV that’s optimized
for smartphones,” he explained. “If you’re trying to watch TV or a video on a
smartphone, and you’re in a noisy place, you can’t hear the speaker. We control
the dynamic range and also do frequency contouring for the speaker, so you get
as much volume out of the phone as possible. It can also make your ringtones a
lot louder.”
in mass-market products, it seems TruVolume stands a good chance of making its
way into your next TV set. “SRS technologies are already in about 40 percent of
flat-panel TVs, so we expect a lot of them will add TruVolume,” Kraemer concluded.--Brent Butterworth
