PRSS Status Update on 6dB Boost Removal

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The PRSS is planning to adjust the audio levels of programs it sends to stations at the end of January 2016 in an effort achieve unity gain across the system. Specifically, a 6 decibel (dB) boost, which was added by the PRSS to analog and digital outputs in 2013, will be eliminated. This will have different implications for stations depending on how they use their IDC SFX 4104 Pro Audio receivers’ analog, AES and Livewire ports. The PRSS plans to issue technical documents beforehand to provide assistance to stations using any of these three configurations.

This announcement follows efforts made, and communications distributed, to take this action earlier in the year. However, the PRSS then determined that additional time and preparation would benefit the system. At the time a 7 point plan was issued outlining the actions the PRSS planned to take before it removed the 6dB boost. Below please find a status report on each of the points we made:

1.            PRSS - Determine where exactly we are not achieving unity gain between producer facilities and PRSS, and where we would need to make adjustments on the day we remove the boost.

Completed Work: PRSS engineers worked with 49 separate producers to test the network lines connecting them to the PRSS NOC. These circuits have been calibrated, and final individual program-level adjustments need to be determined and shared with the content providers.

Remaining Tasks: We have determined that we need more measurement in other parts of the system to ensure that audio levels for live streams and live with subsequent files (LWSFs) remain consistent coming in and going out of the NOC.

2.            PRSS - Craft and publish a schedule for steps 4 through 7 once we have identified these upstream audio points.

Completed Work: The PRSS is aiming to perform the 6dB boost removal near the end of January 2016.

Remaining Tasks: In the next few weeks, we will set a specific time and date. Once this is confirmed, it will be shared with the system along with other pertinent information.

3.            PRSS - Institute a new version of the test signal for stations calibrated at -20 dBFS.

Completed Work: A test stream at the new boost-less -20dB level with a single 24-hour program is in ContentDepot. Any station can subscribe to this transmission using the Join/Leave in Progress [JLIP] process to send the test material to any receiver output port for comparison. In this way, stations can determine new preset levels so that the actual change will be a known quantity when it eventually comes.

The program is called “Test Program Stream” and can be subscribed to in ContentDepot via this link: https://contentdepot.prss.org/portalui/app/#!program/programId=3874954.

4.            PRSS - Coordinate level adjustments with producers of live streams to compensate for the removal of the 6dB boost.

Remaining Tasks: This step will be undertaken once the results from Step 1 are complete.

5.            PRSS - Eliminate the 6dB boost.

Remaining Tasks: The PRSS must confirm and publicize a date and time for this action. This is expected to occur later this month.

6.            Stations - Compensate for the audio shift at their locations.

Remaining Tasks: Once the date has been confirmed, a message will go out to the system advising stations about what to expect when the boost is removed, how to compensate with their own equipment, and when and how they should take action.

7.            PRSS - Adjust levels to achieve unity gain for all other producers not covered in step 4.

Remaining Tasks: There may be a small number of producers who will not be able to conduct a test before we remove the 6dB boost to enable the PRSS to identify a solution in advance. We will help those producers make necessary changes as quickly after the boost removal as possible.

The PRSS is committed to ensuring that this procedure goes as smoothly as possible, and it is prepared to assist any producer or station personnel with questions. Please use the PRSS Help Desk as your initial point of contact so that we may track and monitor all inquiries. You can reach the PRSS Help Desk at prsshelp@npr.org or call 800.971.7677.

 

Posted: November 12, 2015