Loudness-Monitoring Tools Driven by Technology, Market Forces

Manufacturers of technology products that let sports broadcasters monitor and manage audio loudness still constitute a relatively small club, but their wares have changed over the past year based on technological and market forces.

Linear Acoustic President Tim Carroll acknowledges the effects of Moore’s Law, noting that some newer models in the AERO series, including a 5.1 unit and a dual-stereo unit, come with basic features priced around $7,000. And even products that hold their price points, such as the LAMBDA audio and metadata monitor, have undergone operational updates that make measurements easier to read and interpret.

These development trends encourage wider adoption of tools based on the ITU-R BS.1770 standard. “The more that people get used to using loudness-measuring instruments,” he says, “the further upstream they’re used, [and] the less there is to worry about downstream.”

Jeffrey Riedmiller, director of the sound platform group at Dolby Labs, says the shift to file-based workflows earlier in the decade drove Dolby to extend its LM100 loudness meter into the more comprehensive DP600, which has measurement functionality but also incorporates loudness correction, audio conversion, and upmixing.

“The goal was to [enable] broadcasters to analyze program files and non-destructively correct the loudness via dialnorm and dynamic-range metadata carried in coded audio bitstreams,” he explains. “The next generation was about enhanced measurement but also adding the ability to non-destructively work on the audio encoded in the bitstream carried to viewers.”

But more-fundamental market forces also propelled the science of the DP600: specifically, the fact that, as the broadcast environment became increasingly file-based, broadcasts saw an exponential growth rate in digital advertising insertions.

As the number of cable networks proliferated and the need to insert local advertising in file format increased, the ability to measure the loudness and dynamics of the ads’ audio could have been overwhelmed. “It needed an automated and intelligent solution to cope with that,” says Riedmiller.

There were other cues to follow for the product-design process. DaySequerra Corp. President David V. Day notes that his company’s NLC51ST surround-audio–measurement and –management device and its ILM8 loudness meter were introduced in the second half of last year, just as ATSC’s working group was nearing its conclusion and the release of its Recommended Practices document that adopted ITU-R BS.1770.

“We changed a number of [software] items as we monitored what was taking place regarding the ATSC committee,” he says.

Day also notes that a significant amount of the ILM8’s functional design was derived from a specification for loudness metering issued by Jim Starzynski, chair of that committee.

“Measuring loudness is not quite as simple as it appears, even though we have better tools now to do it,” says Day, including the 1770 specifications. “Doing it in 5.1 is that much more complex.”

The next round of challenges won’t be so much technical as operational. Riedmiller raises concerns that the array of pending legislation surrounding broadcast audio could precipitate a lowest-common-denominator mentality among broadcast executives, who are concerned that the solutions are becoming as complex as the problem they sought to address.

“I worry,” he says, “that it’s going to get taken back to NTSC audio in the process of trying to be [compliant] with all the pending legislation. With all the great tools that mixers can use to make the audio as creative and enveloping as possible, it’s at risk of becoming homogenized.”