Same old song and dance

This is not rare. A few weeks later it was Nirvana: “Rape Me,’’ a double dose of “Smells Like Teen Spirit,’’ and an acoustic take on “About a Girl.’’ Then there was a simultaneous Weezer outbreak, followed by a Smashing Pumpkins party, and a Green Day fiesta across the dials.

These days the odds of stringing together more than a handful of songs from bands born in this millennium on commercial rock radio are longer than finding a Candlebox “Greatest Hits’’ album at a Tower Records.

Each of Boston’s commercial rock outlets brands itself with an identity. WAAF-FM (107.3/97.7) layers vintage, hard-edged rock from Guns N’ Roses and Van Halen along with tracks from newer bands like Shinedown. WXRV-FM (92.5) tends toward singer-songwriter fare, which gives it room to include everyone from a veteran like Neil Young to a newcomer like Sondre Lerche. Although Radio 92.9 (WBOS-FM) casts a wider net to include mainstream ’90s acts like Matchbox 20 and the Dave Matthews Band, it is the most conservative about plugging new stuff into its DJ-free jukebox format. WFNX-FM (101.7) shuffles a heap of the new names in alternative rock - Vampire Weekend, MGMT, Passion Pit, Phoenix, and the xx - into a deck that includes seminal modern rockers like the Pixies and Mission of Burma.

So, it’s not that the stations aren’t playing new music, or even different old music. But where they overlap is practically identical.

The core ’90s modern rock groups - the Seattle four of Nirvana, Pearl Jam, Soundgarden, and Alice in Chains, plus other stalwarts like Red Hot Chili Peppers, Sublime, and Green Day - make up a healthy portion of each station’s menu. It’s enough to make a fan wonder why in 2010 everybody’s simultaneously partying like it’s 1994.

Since WBCN, which had similar overlaps format as these stations, signed off in August, have any of the other rock stations benefited?

No station has claimed the lion’s share of ’BCN’s listeners, judging by the Arbitron ratings. Between August and December all four stations essentially held their spots in total audience share.

Mike Tierney, vice president of broadcast operations for WFNX and Phoenix Media, isn’t surprised. “I think everything about [WBCN’s] brand identity was so muddled at the end that anybody who was listening, was listening by something like happenstance or habit.’’ Mistress Carrie, music director and afternoon drive personality at WAAF, points out that ’BCN’s audience had shrunk enough that “there weren’t that many people to divvy up.’’

In fact, the biggest beneficiary has been WBCN’s replacement, sports talker WBZ-FM (98.5) and its owner, CBS Radio. Since abandoning the grunge wars, they have surged ahead of where WBCN was in audience share.

“Sports stations target the same guys as alternative - at least the 30- or 40-year-old guy who listens to alternative - which is one of the reasons that rock radio hasn’t quite been the dominant force that it used to be,’’ says Sean Ross, vice president of music and programming at Edison Research, a media research firm. “So it’s probably a pretty good station for a lot of the ex-WBCN people and, hey, it has Toucher and Rich, too,’’ he says, referring to former ’BCN morning team Fred Toettcher and Rich Shertenlieb. (The luckiest survivor in the shuffle is former ’BCN DJ Adam 12, who landed at his old home at WFNX, and now holds down the afternoon drive slot.)

As for the pervasive ’90s-leaning playlist itself, most agree it’s a simple matter of Generation X yearning for a time when they didn’t have mortgages and minivans.

“It’s a reflection of what happens to us all as we get older, where we feel nostalgic for the music that burned brightest at the time we were most vulnerable to it: as teenagers and twentysomethings,’’ says Catie Wilber, program and music director at WXRV. “That has become one segment of the audience’s classic rock.’’

It is not, however, as popular as the format actually called “classic rock.’’ Because both the baby boomers and Generation Y remain substantially larger than Gen X - and younger people consume music in more diffuse ways, from iPods to Internet radio - the classic hits stations like WZLX-FM (100.7) and WODS-FM (103.3), and the Top 40 outlets like Kiss 108 and Mix 104.1, remain the top-rated signals. There isn’t a single alternative or rock station in the overall top 10 of the Boston Arbitron ratings.

“The ’90s is a real hot button,’’ says Ken West, program director at Radio 92.9 as well as oldies outlet WROR-FM (105.7). “Most of the input we get says, I love that you play songs that were on when I was in college.’’

So it’s no surprise that Soundgarden and their ilk dominate the rock stations. “Those bands are the Led Zeppelins of the previous generation,’’ says Carrie. “Pearl Jam is that big.’’

Still, for people who listen to radio as a method of discovery, this can be disappointing. College stations still introduce listeners to new music, but commercial stations have become more circumspect, carefully calculating ratios of old to new.

“I would argue that discovery still happens at radio, but it happens a lot of other places, too,’’ says ’FNX’s Tierney.

Indeed, in the social networking age, “new’’ has shifted to a new platform. “I remember when I was on the air at night, record reps used to drive around outside radio stations and hide CDs in the bushes and then call us all at the same time so we could all play it at the same time,’’ says Carrie. “Now it’s like, OK, it’s available for download, here you go. It’s already been streaming online for weeks or it got released to the fan club. The Internet just changed the way people use radio.’’

So while all of these stations do shine a spotlight on new artists, they still rely on the ’90s because what people say they want and what they actually want, judging by ratings, isn’t always the same.

“People say they want to hear new stuff but behave like they enjoy the stuff that they’re familiar with,’’ Tierney says. “And I think a good balanced radio station meets both expectations.’’

West at Radio 92.9 agrees and says the wait-and-see approach to new artists like Muse and Phoenix works for them. “A lot of times there’s new music out there that ’FNX will play that either we won’t play or we won’t play it as soon as they play it, because they are the station in the market that is known for being cutting edge. We don’t claim to be that, and we don’t try to be that, because the audience doesn’t expect that from us.’’

In some ways, the cornucopia of rock music is itself to blame for the reliance on oldies. Not that there isn’t compelling music being made, because there is, by artists as diverse as La Roux to Bon Iver. But radio is a business, and perhaps there’s simply not enough of that music that appeals to a wide enough audience.

“The biggest thing contributing to that is just how fragmented the rock landscape has become,’’ Tierney says. “The diversity that runs from Passion Pit to Chevelle and everything in the middle - it’s really difficult for one station to serve all those niches. I wouldn’t argue that anybody should try. You have to pick your lane.’’

There’s evidence that this brand of classic rock is winning listeners. Stations in cities such as Philadelphia and Los Angeles that have switched to a ’90s alternative format have found success in the past few years, says Edison Research’s Ross. “The ’90s alternative just has a much larger quorum than today’s alternative,’’ he says. “There’s just so many more people who can agree on Stone Temple Pilots and Pearl Jam than Vampire Weekend.’’