The latest recipe for success in broadcast radio? Dump a thousand or so random songs into a playlist. Hit shuffle. Then, more often than not, kill the live DJ and replace him with a computer.

This is the so-called Jack format that’s riding radio waves all across the U.S. In the last three weeks alone, the format, or a close variant, has debuted on stations in five major metropolitan areas — Los Angeles, San Diego, Chicago, Philadelphia, and Indianapolis, adding to the half-dozen or so that had switched since Denver inaugurated the format in the U.S. a little over a year ago.

Will the new format be enough to rescue broadcast radio from its creative doldrums? I have my doubts.

The rules guiding a Jack-formatted station are simple: Unlike a typical radio station, which regularly plays 300 or 400 hits of a particular genre, programmers on Jack stations select 700 to 1,000 songs of completely different genres. Then, they sequence them to create what radio programmers call “train wrecks” — Billy Idol will follow Bob Marley, Elvis after Guns N’ Roses, and so on. And Jack stations often (but not always) use a smart-alecky recorded voice, rather than a live DJ, to make short quips between songs.

REBEL RADIO? Broadcast radio lately has come under increasing fire from critics and competitors for being bland, repetitive, and overly commercial. While traditional broadcasters still dominate market share, new technologies are growing fast.

Last week, XM Satellite Radio (XMSR ) announced it had added 540,000 subscribers in the first quarter of this year alone, bringing its total base to almost 3.8 million. Meanwhile, consumers are increasingly turning off normal radio and clicking into MP3s and streaming audio feeds over the Internet, according to a recent survey by radio consulting and research firm Jacobs Media.

Programmers hope the looser Jack format will show just how edgy and fresh they can be. “We’re not going to be constricted by radio rules,” says Peter Smyth, CEO of Greater Media, which owns 19 radio stations and debuted its first Jack station, Ben-FM, on Mar. 22 in Philadelphia. “[We’re doing] all the things satellite companies say we’ll never do.”

Listening to Jack is a bit like listening to an iPod set on shuffle. Sandy Sanderson of Canadian media company Rogers Communications (RG ), who first developed the format for a Rogers station in Vancouver in late 2002, says he didn’t initially have an iPod in mind, but admits there are similarities. And many think this is one of the keys to the Jack format’s appeal, especially as broadcast stations compete with MP3s, Internet feeds, and satellite radio for consumers’ ears.

HIT PARADE. “It’s part of a real shift in how people consume media” says Mike Stern, programming director for alternative rock station Q101 in Chicago. On Apr. 1, Q101 “jacked up,” its format. While it still plays solely alternative rock, it tripled the size of its playlist to include selections from the last 20 years, not just the latest hits. “It used to be if you wanted to rent a movie, for example, you went to the Blockbuster (BBI ) and there were 3,000 titles. Now you can go to Netflix (NFLX )” and choose from 40,000, says Stern. “Now, instead of having a 6-CD changer in your car, you get an iPod.”

But if the Jack format is an iPod, it’s everyman’s iPod. The playlist at a Jack station is generated by computer, but sometimes tweaked by human hands for maximum effect. The one rule of Jack is that while songs can be from any genre and line up in any order, all must have been Top 40 hits at some point in the last 30 years. So, paradoxically, while the mix is eclectic, the songs themselves are pretty predictable.

A couple of weeks ago, when I was in Los Angeles, without a familiar radio station to turn to, I tuned into 93.1 Jack-FM, an Infinity Broadcasting-owned station that switched to the format on Mar. 19. My reaction? Jack-FM beats most normal radio stations. With less talk and more music it feels like there are fewer ads.

The format does keep you listening — if sometimes only out of faith that the next song will be completely different. And if you’ve heard some of the songs a million times, there’s consolation in the probability that the million times came years ago. In that way, it’s just short of genius how the format kept me patiently sitting through several songs I’ve never really liked.

More here.