Here's a place to at least begin:
- 50% of the average station's most-exposed categories contain songs by unfamiliar artists, thus I'd code for "major superstar," "familiar to the core but unknown to many of the cume" and "new to even the heavy users," making sure ever other song is from a well-known voice. Yes, that causes the music scheduler to groan but the exercise is worthwhile - the listener is never far from a familiar voice.
- Tempo is the second major issue. Almost every category averages 40% slow, if not even more. The tempo, energy and mood rules we recommend make scheduling tricky, but are important.
- Repetition is controlled by use of extremely restrictive tight hour-repeat rules. This also presents the potential of scheduling nightmares, but it's worth doing.
I think we can be reasonably flexible with all other parameters, but these are the big three…familiarity, tempo and repetition.