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PPM Encoding Issue Heats Up Prior to NAB Show

Questions swirl over Voltair PPM encoder

In advance of the NAB show questions about the PPM encoding process are becoming more strident as Telos Alliance member 25-Seven Systems plans to display its Voltair PPM monitor.

“The spectral characteristics of your audio content — music, announcer voices, etc. — may negatively impact the robustness of your watermark encoding. Simply put, some audio content encodes well while other content does not,” says 25-Seven Systems on its website.

The Voltair confidence monitor “monitors and displays PPM encoding quality based on program material, enabling programmers to simulate decoding quality in various listener environments and actively process the signal to optimize PPM encoding based on adjustable parameters,” according to 25-Seven Systems.

Nielsen has always maintained that all audio is encoded, including soft music passages, and talk formats, which have breaks in the audio.

Yet, some engineers and programmers have questions about the effectiveness claims of both companies regarding PPM encoding.

At a recent joint Washington-Baltimore SBE Chapter meeting, one engineer characterized these questions as “encoding anxiety.”

“The new encoder has something to alleviate that!” quipped John Stavropoulos, vice president Engineering & Supply Chain Management, for Nielsen. The meeting was held at Nielsen in Columbia, Md., and he discussed Nielsen’s new PPM encoder and confidence monitors.

He told attendees the audience research firm is conducting in-house testing of the Voltair. But Stavropoulos was also clear he had no comment on the unit.

25-Seven Systems says it has some 300 Voltair units in the field.

Nielsen, too, has around 300 of its new encoders in the field out of about 11,000 total, Stavropoulos told Radio World. Nielsen still provides clients with a main and a backup encoder; however it encourages all stations in a market to encode for PPM, even nonclients.

Nielsen is replacing current encoders with new ones for stations that are doing a rebuild, new stations or for those whose unit is broken, for example.

In a memo sent to client stations, Nielsen has reportedly reiterated that it’s testing the unit and recommends clients hold-off on using the Voltair until tests are complete and results validated. Telos Alliance CEO Frank Foti responded with a client memo titled “Nielsen Schmielsen!”

Saying that customers are buying the Voltair, Foti says in his memo that “some of our customers feel bullied by Nielsen.” He notes the audience research firm actually doesn’t recommend “any audio processor.”

“Audio processing has evolved dramatically in the last 20 years, while PPM has not,” according to Foti.

At the SBE meeting, Stavropoulos said Nielsen made upgrades and added more functionality to the PPM encoder, the meter and the monitor in 2014. For example, the Anadig encoder is a combination analog and (AES) digital radio encoder. The new encoder is also half of the depth of the old one, he noted.

The PPM 360 V2 meter has added cellular technology, a 100-hour battery life, a standard micro-USB connector and improved water resistance, as well as an improved digital signal processor for more headroom, he said.