Goodbye, classic rock. Hello, Bob.

WRRK-FM (96.9) has flipped to Bob FM, a varied format aimed at a wider audience that includes its former classic-rock listeners. The station made the switch at midnight yesterday.

The hybrid music format, better known as Jack in most markets, is a mixed stew of a playlist, stretching from the '60s to current hits.

Programmers see it as a way to engage radio audiences who've grown tired of formulaic, corporate formats that are heavy on commercials and light on variety. The target audience is 25- to 54-year olds, and listeners are about a 50-50 balance of male and female.

"We felt we had a unique opportunity," said WRRK program director John Robertson. "The variety hits format has been super-successful in several markets. We think it can be very successful here."

While Jack formats are completely automated -- no DJs, weather or traffic -- the Bob formats do employ DJs. WRRK will run on automation for a while, Robertson said, adding that they plan to bring in air staff, possibly some present WRRK personalities, at a later date.

With a new ID -- Bob FM 96.9 -- WRRK is all over the musical map.

The format was the brainchild of former DJ Bob Perry, who launched an Internet radio station called jack.fm. Using software that played songs in random order, it created a "train wreck," where a ballad could be followed by a heavy metal head-banger or a rock hit could follow an R&B classic. He sold the idea to a station in Vancouver in 2002, where it took off.