Recently Nielsen touted ratings growth coinciding with the roll-out of enhanced PPM encoding (eCBET).
According to Nielsen, the enhanced encoding, "Makes the PPM codes stronger and more robust, which improves code detection in challenging acoustic environments."
Unfortunately, as a consequence of stronger and more robust encoding, the encoding tones seem to be much more apparent. The sound of the tell-tale buzz-saw sound of encoding is now a regular feature of some encoded radio stations.
(At the bottom of this post you’ll find a link so you can hear what it sounds like.)
Back when PPM was being developed engineers told Arbitron executives that the only way to make encoding work reliably was to make the encoding tones audible.
Since few radio listeners enjoy the sound of buzz-saws, Arbitron decided to lower the level of the encoding tones anyway.
Voltair demonstrated the extent to which the decision hurt radio ratings. Some formats were losing upwards of 30% of their listening credit, and Voltair was giving a good chunk of that back.
Faced with incontrovertible evidence that PPM was not capturing all of radio exposure Nielsen had to do something.
So they cranked up the tones.
Yes, it helped radio station ratings, but at what cost?
The enhancement appears to have been an inelegant blunt-force effort to block Voltair. And in the process it bludgeoned programming quality.
It makes the tones more apparent in the oddest places.
The buzz-saw becomes most apparent in programming that already encoded well. High density midrange stuff seems to trigger the loudest encoding. Meanwhile, the stuff that was poorly encoded has seen limited improvement.
It’s true that Voltair could conceivably produce a similar problem, but it only appears when Voltair is turned up too much. Turning it down makes the problem go away.
With eCBET, Nielsen sets the level of audibility. You have no control. You’re stuck with audible encoding and no way to reduce the effect.
Listeners often choose one station over another for reasons other than format. Sometimes they gravitate to a station just because it sounds better.
Higher perceived audio distortion (and encoding tones sound like the worst kind of distortion) has the potential to drive listeners away.
Research has shown that listeners react negatively to noise:
When activity between the auditory and emotional parts of the brain increases, it may cause a sensation of revulsion or disgust at a sound, as typically occurs to most of us when we hear somebody scrape chalk or their nails on a blackboard.
When we hear unpleasant sounds, the auditory cortex and the amygdala interact more intensely and process the negative emotions. The amygdala is a small almond shaped part of the brain that processes our emotions and aggression. It also controls fear responses and forms emotional memories.
Wouldn’t be ironic if the battle to fix flaws with PPM ultimately drove people away from local radio because eCBET made radio unlistenable?
Once you know what you are listening for, you'll begin to hear the buzz-saw sound of encoding on many stations. Here's what continuous encoding sounds like: