PRSS to Make Loudness Data Available to Producers

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Beginning Tuesday, April 7, 2015, public radio producers and distributors will be able to view in ContentDepot the Loudness measurement data associated with their uploaded program segments. The move is a key component of the PRSS Loudness standard, which was released earlier this year (for more information about the standard, please visit

Since January of this year, all files uploaded to ContentDepot have been measured for their loudness readings. Until today’s announcement, the data was not visible to users. Now, when a producer visits his or her program page, the data associated with each of the program’s segments is listed along with a notification on whether the segment is inside or outside spec (see attached diagram). Producers can also access a report providing historical data on the loudness of their programs. To access this report, users should go to the ‘Tools’ drop-down menu in ContentDepot, select ‘Reports’ and then select ‘Loudness Report’ to view the data.

The PRSS Audio Loudness Standard has been set at -24 LUFS, ± 2 LU, audio peaks = -3 dBFS for sample peaks or = -2 dBTP for True Peaks, meaning producers should strive to set their programs’ audio levels at -24 Loudness Units Relative to Full Scale (LUFS), with a deviation range of plus or minus two Loudness Units and an audio peak at or below -3 dBFS or -2 dBTP.

At this time, the only users authorized to view a program’s loudness data are the producers of that particular show. PRSS officials said they hope that sharing the loudness data with producers and distributors will help them self-correct any discrepancies with the loudness of their shows. PRSS staff will communicate through a variety of means with distributors and producers requiring assistance in meeting the PRSS loudness specification.  For the immediate future, PRSS plans to take a wait-and-see approach to ensuring compliance with the loudness standard.  

“We’re confident that once our producers are provided the loudness data on their programs, they will be motivated to ensure their content meets the PRSS standard,” said Michael Beach, Vice President of NPR Distribution, which manages the PRSS. “Ultimately, our goal with the PRSS loudness initiative is to improve the radio experience for the listener, and I know that all producers, distributors and stations share that goal as well. And our intent is to take the least intrusive approach as possible and monitor and inform the producer community, not modify or reject content.”

Those attending the PREC Conference in Las Vegas  from April 9-10, 2015, will have the opportunity to hear more about the PRSS loudness standard and pose questions to those who helped develop it. The panel discussion, moderated by Chris Nelson, NPR Director of Technology Strategy & NPR Labs, will be held at 10:45 AM on Thursday, April 9, 2015. Panelists from NPR Distribution will include Director of Product Development Jim Duff and Director of Engineering Mark Murphy. Also appearing will be John Kean, senior technologist at NPR Labs, and Rob Byers from American Public Media, who have been instrumental figures in developing the PRSS loudness standard.

If you have any questions or concerns, please contact the PRSS Help Desk at 800.971.7677 or


Below are a sample of Frequently Asked Questions about the PRSS loudness standard. A more complete list can be found at

What is “Loudness”?

Loudness is a way to more accurately measure audio levels based on the way humans perceive sound. Unlike traditional digital peak meters that reflect only the highest peaks in an electrical signal, loudness meters evaluate audio considering multiple psychoacoustic factors and generate an easy to read numeric value. If each producer mixes to the same loudness target, public radio content from myriad sources should have consistent levels throughout the system, providing an improved experience for the listener.


Why is the PRSS issuing a new standard?

For several years, PRSS staff have heard from stations that varying audio levels were a problem. A subsequent analysis of material in the system confirmed that audio levels varied widely. Updating the standard and developing feedback tools began in early 2014. Using loudness as the way of measuring levels should facilitate this desired consistency.


When will it take effect?

In January 2015, the PRSS began monitoring audio levels of file-based programs uploaded to ContentDepot. Beginning on April 7, 2015, the PRSS will begin to share the data from monitoring file-based programs with the distributors and producers of those programs. Later in the year, data on live streams will be shared as well.


Will there be any differences in the standard between LWSFs, live streams or file-based programs?

The PRSS standard will be the same for all programs, file-based, LWSFs or live streams. In addition, all promos and underwriting spots will also be analyzed.


Does this only affect my content that is distributed by the PRSS? What about content handled by another distributor?

Other distributors may adopt this or another loudness-based standard, but this applies only to programs distributed by PRSS.


Is there a way to see how my show compares to other productions in the system?

The PRSS does not make available the loudness measurements from one producer’s content to any third parties, and producers will only have access to ContentDepot loudness data on the programs for which they are responsible.



Posted: April 6, 2015