Rare Frequency tells us that the Muzak company has filed for bankruptcy. They also link to a more interesting New Yorker article, though, about the company and how it reinvented itself as a kind of sonic psychology company that customizes the aural environment (ie. background music) of many shops and restaurants you walk into. Visiting the headquarters, the author David Owen discovers:

Naturally, there’s an awesome sound system, which extends into the parking lot but not (for deeply felt symbolic reasons) into the elevator.

Apparently they tried branching into CCTV systems after 9/11, but that didn't pan out:

Collis told me, “With audio branding, you’re selling emotion, love, caring, feelings. With CCTV, you’re selling fear. Not a good combination.”

I can still remember the first time I saw a Muzak control (or something like it) in the wall of an office - it was some building on St Kilda Rd that a friend had a holiday job in, and I popped in to say hi. I seem to remember him telling me about this great new replacement for PKARC called PKZIP (geez, those were the days, huh?), but I was drawn to this volume control on the wall with a little speaker below it - I turned it up for a moment to hear what the music was like, but it wasn't long before it went back to its seemingly natural resting position of "off". Maybe in earlier times...