ATSC Ready To Solve Loudness Woes
By: Ken Kerschbaumer, Editorial Director
Wednesday, October 28, 2009 - 10:09 am

The TV-broadcast industry is expected to take a major step toward solving the loudness problem next week, when members of the Advanced Television Systems Committee (ATSC) are expected to approve ATSC Loudness Recommended Practices (RP). The practices will be known as ATSC A/85 and will give TV stations and networks more guidance, so that programs and interstitials have more-consistent loudness levels both within a station’s DTV signal and between one channel and the next.

Jim Starzynski, who led the Loudness Group that defined the practices and is principal engineer and audio architect of NBC Universal, discussed the ATSC’s progress this week at the SMPTE Tech Conference in Hollywood. The approval of an RP comes just in time for the industry, as lawmakers in Washington have taken the issue into their own hands with the CALM (Commercial Advertising Loudness Mitigation) Act. The Act, sponsored by Rep. Anna Eschoo (D-CA), currently sits as an active bill with the House of Representatives telecommunications subcommittee. And given the public’s hatred of loud commercials, it is expected to pass easily.

The ATSC practices, however, will limit the bill’s potential impact on the industry. “Legislation should be unnecessary, and we will be able to monitor ourselves with the RP,” says Starzynski. “And while there is a chance the legislation could have slowed down the work of creating the RP, we have worked with lawmakers to mark up the bill in a fashion that points towards the recommended practice as a solution.”

The problem of loudness has become more pronounced for TV stations, networks, and viewers now that the transition to DTV is complete. Analog broadcast signals were not robust enough to deliver an audio signal with a tremendously wide dynamic range. But digital signals can have a dynamic range as wide as 100 dB. “You need to monitor the audio well to deliver an audio experience that customers are used to,” says Starzynski.

A major component of the RP involves requiring all incoming content, whether programming, commercials, or other content, to be submitted with audio set at -24 dB (±2 dB). By having all the networks and stations agree to one specific audio level, creators of commercials can more easily meet that requirement. “It costs money for the producers of commercials to make different mixes for different networks. We knew it would be terrific if we agreed on the same [level], and we did,” explains Starzynski. “It’s a great achievement.”

Among those involved with the project were NBCU, CBS, Starz, HBO, ABC, and PBS. Besides the Content Loudness Recommendation, the RP covers such topics as Loudness Measurement, Setting Up Audio Mix and Monitoring Environments, Using Metadata, Dynamic Range Control, and Methods To Control Program Interstitial Loudness.

It will also have two quick reference guides for cable channels, broadcast stations, and networks.

NBC Universal has worked on turning the theoretical practices into reality this year. New software technology at WNBC New York and the NBC Network Operations Center is solving the problem of consistent loudness levels when content exists only as a file on a server.

“It takes the measurement of the file at the beginning to determine how loud it is and how loud it needs to be,” says Starzynski. “Then, during the transcode process, the loudness is changed.”

NBC Universal has also installed loudness meters within the audio-mixing environment so that mixers of live programs can make sure the mix leaves their desk meeting the need for audio at the -24 dB level. And the Linear Acoustic Aeromax is in use by NBC cable networks to deliver more-uniform loudness levels. “It’s very effective,” says Starzynski.

“Right now,” he adds, “we’re asking Hollywood to get it right and deliver content the way we need it delivered. If that happens, the system will work transparently.”

Anyone looking to learn more about the recommended audio practices will want to attend a special one-day seminar on Nov. 4 at the ATSC office in Washington. For more information, visit

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