Check those levels. PPM signals embedded in your program material could fall below the threshold so your station isn’t heard by Portable People Meters that track your listenership.
Does audio processing have an affect on PPM ratings? You bet it does, according to our audio engineer Mike Erickson. "The biggest issue is making sure that audio levels don't fall below a certain threshold," he said. PPM encoders will stop encoding audio, as many have found out, if they are not fed a steady diet of audio. "When the encoder stops, the PPM (encoded) signals can no longer be 'heard' and detected by PPM devices that track listenership," he added.
An easy out is to put an AGC in front of the encoder, and any Wheatstone audio processor will be able handle that with ease (our stuff can actually adapt to external processors without any user adjustment). For other processors that are not self-adjusting or even for ours that are, Mike suggests broadcasters establish a standard set of reference levels for audio sources as a guideline for board operators who load music, imaging and spots into the automation system.
This includes playout sources and microphones, as well as audio levels of callers' voices going into recording software like VoxPro. Separate processing for DJs and callers can go a long way to keeping levels balanced. "You can then run the board without worrying about your levels because everything has been set, and now that external AGC isn't needed in front of your PPM encoder," explained Mike.
In addition, he said that operators should be mindful of the meters and how hot they run the fader levels, so that the microphone level is not 10 dB higher than the rest of the programming, for example. "Being very careful with console levels helps not only with things like PPM encoding, but also helps the processor do a better job because you're not constantly fighting various input levels from source to source. It will make the whole station sound better."
Which, in turn, will also affect PPM ratings.