From the New York Times article;

My previous look at how Muzak works, as described in The Recording Angel is a rather outdated description. The NYTimes article summarises how the the company has evolved.

The architect rates the song in 45 detailed categories: the mood of the music; its instrumentation; its color (dark or light), and whether it is by a male or female vocalist. Once analyzed, the songs are assigned what the company calls ”quantum modulation” figures and stored in the database for future retrieval.

Every day, audio architects assemble 24-hour playlists, ranging from country to pop hits, for 60 broadcast channels. Songs are selected, Mr. Collis said, to provide the necessary blend and balance of stimulation throughout the day. ”We want to create an atmosphere that is dynamic and constantly changing,” Mr. Collis said. ”We don’t want to be boring.”

With the database updated, Muzak representatives meet with prospective clients to create an ”audio image” — a musical personality. They examine the client’s marketing goals, mission statement and products, then suggest an appropriate Muzak program. A shoe store in a rural area needs to keep kids mellow; maybe the country channel might be appropriate. An urban sneaker store wants to enhance the customer experience; how about Muzak’s channel with Puff Daddy songs?