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Originally featured on BroadcastEngineering.com
Apr 12

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4/12/2012 3:14 PM  RssIcon

Self-Automated Surround Sound Audio Monitor an Affordable, Innovative Loudness Solution

pbs_media-operations-center_sentinel_photo2.jpgARLINGTON, VIRGINIA, APRIL 12, 2012 - When the media operations center at the Public Broadcasting Service (PBS) sought a solution that could comprehensively measure 5.1 loudness, it turned to the Sentinel Surround Sound Audio Monitor from Qualis Audio, a leading developer of professional audio measurement and monitoring instruments, with an emphasis on 5.1 surround sound. The Sentinel, with its extensive range of QoE measurements and ability to visualize both real-time and logged measurements, has significantly streamlined the center's workflow, enabling staff to meet the stringent loudness and quality control requirements enacted when it transitioned to HDTV and 5.1 surround sound.

PBS's media operations center in Arlington, Virginia, receives, evaluates and produces the final preparation of all programming content scheduled to air across the broadcaster's various nationwide member stations. To ensure this material meets PBS's strict Technical Operating Specifications, staff watches all programming in real time, comparing the final broadcast version to other processes. And while PBS is not currently required by the CALM Act to meet loudness requirements because it does not run commercials, it still monitors loudness in accordance with the ITU1770-1 standard, a critical step in the entire process.

"A number of PBS members worked on implementing the CALM Act, and we believe it's a service that is in the public's best interest, so we make sure to evaluate every program that comes in and reject anything that does not meet our loudness guidelines," says Steve Scheel, senior director, Media Operations Center, for PBS. "PBS distributes a large number of programs in surround sound and is very aware of the differences in loudness in 5.1 surround as opposed to stereo downmixes, so we are very keen to solve the problem upstream when we can. Having the Sentinel at the media operations center has allowed us to meet our criteria on a variety of program materials and audio formats."

In addition, the Sentinel's downmix compatibility of 5.1 audio is carried out unattended with complete archiving of all measurements. This provides documentation for a MTR (Media Trouble Report) when a program fails to meet the TOS guidelines for submission. Scheel is also able to record an entire program, then cut the program into various pieces and reassemble it for distribution on other platforms and have the Sentinel measure individual segments of loudness after the fact. "No other device has done this for us," he says. "It is amazing how much time it saves."

Scheel and his team also rely on another unique feature of the Sentinel, which is the logging it performs on each program. The log is beneficial to the station, as it can be kept for years; any time a complaint comes up, PBS can go back to when it originally ingested the content and verify that it was done correctly. Now that broadcasters are required to abide by the CALM act, with potential fines of several thousands of dollars for non-compliance, the log is especially invaluable in these cases.

Prior to installing the Sentinel, Scheel and his team at PBS measured loudness using another product. Two of these products were installed in each of the broadcaster's four media rooms as a workaround for measuring 5.1. Not only was this solution expensive, it didn't measure correctly - staff had to add all of the channels

together in order to do so. PBS needed a solution that would operate in a base-band environment, where the discrete program channels needing to be evaluated live were measured. Other solutions required PBS to create a Dolby E stream each time staff wanted a measurement, a costly and time-consuming process. The Sentinel enables PBS to view loudness in surround and stereo at the same time. Plus, with its continuous software upgrades, it has set the staff up for any future changes that may occur, such as the acceptance of ITU1770-2.

"Qualis Audio recently added a number of new features, especially now with talk that the CALM Act might also include the newer European Broadcasting Union's (EBU) ITU1770-2 regulation [which includes a loudness gate]," explains Scheel. "The Sentinel's new features allow us to compare what would happen if the newer standard came in and allows us to look at the European standards that are being used as well. It's a very versatile meter in that if you wanted to take a look at the way the Europeans do it, we can do that, if we want to take a look at the CALM Act, we can do that; if we wanted to experiment with the gated function we can do that too. The Sentinel has become extremely useful. For us, it's the perfect instrument and it meets all of our needs and is an investment we needed to make."

Steve Wynn, director, engineering and maintenance, Media Operations Center, PBS, echoes Scheel's sentiments, explaining how crucial it has been for the broadcaster to find a solution that works with the center's existing equipment.

"It is so refreshing to have a critical component, such as the Sentinel, that's so well designed," says Wynn. "It has its embedded operating system, talks nicely on the Web and it's a controlled environment, so it's more secure. Plus, we have always received positive support from Qualis Audio. They were very helpful with the installation and setup, and continue to be as changes come in. The issue of loudness isn't over and it has been worth the initial investment to have a solution that will grow with the changes and the issues."

The Sentinel Surround Sound Audio Monitor measures, monitors and logs loudness and virtually every other parameter necessary to ensure optimum audio reaches broadcast viewers. Its measurement and logging verify and document CALM Act compliance, conforming fully to all ITU BS1770, ATSC, FCC and EBU requirements. Any deviation outside of the allowed range automatically generates alarms to the user's choice of SNMP, email or GPI. The Sentinel also measures, displays, logs and alarms all pertinent audio parameters, such as the new downmix loudness capability described above, downmix compatibility, hum, balance and other parameters required for quantifying audio quality.

"We are so pleased that the Sentinel has helped such a prestigious broadcaster as PBS solve its issues with monitoring loudness," says Rich Cabot, president and CTO, Qualis Audio. "We admire PBS for providing its viewers with quality content and the best possible broadcasting experience possible. Those beliefs run parallel to our goals for the Sentinel - to capture the integrity of audio and deliver it to listeners as it was meant to be heard, while still in compliance with current regulations."

For more information about the Sentinel and Qualis Audio, visit www.qualisaudio.com or call 1-503-635-9376.

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