It's only rock'n'roll, but who reads it?

Once, music mags were inky notes from the underground. Where do they go now rock's on Radio 2 and the info's on the Web?

There was a time when music magazines defined youth culture, when we turned to the rough pages of NME or Melody Maker to read about one of the most important things in the world: music. But recently music magazines seem to have lost their biblical status.

This year, they recorded massive falls in circulation. According to the ABCs, NME's sales dropped 16 per cent, and Melody Maker and Select were down 21 per cent. Even Smash Hits fell 18 per cent. Only the older-marketed titles, such as Q, stayed ahead of the trend. Dance music titles, however, were up by a fifth.

Like the youth they aim at, it seems the rock journals are having a bit of an identity crisis. Select, the indie bible, has relaunched in its new lo-fi, style-mag format, following a massive redesign under new editor, Alexis Petridis. Last October, the weekly Melody Maker showed its spotty face to the world in its new glossy A4 format, finally distinguishing itself from its sibling the NME. And BBC Worldwide has announced that it will spend £500,000 on Top of the Pops magazine.

But five or 10 years ago, music-obsessed youth was an assured market, so why aren't the old favourites attracting the new generation? Pop music is about identity, and music magazines reaffirm that identity, connecting people to a world of like-minded individuals. Once music magazines provided the main link to the world of street cred and cool; now young people are faced with more choice than ever.

"The NME is a case in point," says Q's editor, Andy Pemberton. "They're basically for students. Now you'd think that was great, because there'll always be students, but the problem is that they have to get their readers to care passionately about the Stereophonics, and I don't think they do any more. I don't think people who are 18 need pop music in the same way they used to when that was all there was. Now there's a plethora of things on offer."

The rise of men's magazines such as FHM and Loaded has cut into sales, and the internet is now the premier source for obscure music. "Before, music magazines were very much a place for music information, but there's much more online now," says Robert Tame, publishing director of IPC's music and sport, which includes NME and Melody Maker.

NME's long-time editor Steve Sutherland has been made "brand director" and now oversees radio, TV and online projects, including Nme.com - currently the most popular UK website. Of course people will still want to read from a magazine, but the trick is to remain relevant. NME's new editor, 26-year-old Ben Knowles, plans to reintroduce humour and single-issue politics. Recently, NME ran a front page on cannabis, and last week's London edition featured Ken Livingstone as part of a musical campaign to support his mayoral candidacy.

Ultimately, however, music magazines are contingent on the music industry, and when that hits a trough, so will they. At the height of Britpop, with bands like Oasis and Blur, British music seemed unstoppable. There were plenty of personalities to write about. But the music that the magazines promoted has since become all pervasive, and the rock scene has hit a slump.

"In 1995 and 1996 we had this incredible moment when we all agreed about everything," says Andy Pemberton. "Most people voted Labour. Everybody liked Oasis. There was Britpop, and Brit Art, and Chris Evans. So it was an incredible time - a sort of spasm of excitement. In comparison, you could say that now is a bit boring, frankly."

Select magazine, which launched in 1990, in many ways predicted Britpop and rode the wave of its success, only to crash on the other side. "Indie music is a really nebulous thing now," says editor Alexis Petridis. "Travis get played on Radio 2. So I think [Select] lost its direction and stuck with that old Britpop model when things were changing."

The problem with consensus culture is that it's not cool to like the same bands as your mum. Music needs to be rebellious, which is why we're seeing the rise of the parent-offending new metal bands.

Petridis says that many people feel disenfranchised by the music press, and Select hopes to draw them back. They've ditched the student image and made the magazine more open, adult, cool and "responsive". The focus will be broader, too, reflecting current tastes.

Meanwhile, the 73-year-old Melody Maker is having its second childhood. The magazine, considered by some to be a secondary NME, gradually broadened direction, targeting a slightly younger audience. The format change was the last piece in the jigsaw. But not everyone is convinced. Andy Pemberton says it isn't the answer. "It looks like they're trying to be indie for people who've just grown out of pop music. I don't know whether those people really exist."

Officially audited figures for the new format, however, were 11 per cent higher than the last ABCs. Editor Mark Sutherland says there are signs the music industry is waking up and there's no lack of an audience. "We have hundreds of letters from people saying 'I'm at sixth form college, and I can never get the kind of music I like on the stereo.' Being into alternative rock, by definition, makes you different. We're not a mainstream publication, we're an alternative publication."

Dance magazines, however, are thriving, and this is another perceived threat to the rock journals. Although much of their success is due to monthly CD covermounts, club culture is on a roll. Tom Whitwell, appointed editor of Mixmag in March, says dance magazines are more innovative than other magazines, embracing mixed media and involving readers in all aspects of club culture.

Many magazines have appointed new editors and managers. IPC has just recruited Mike Soutar - responsible for FHM and Maxim's success - to turn around its music and sport division. This follows the resignation of board member Andy McDuff two weeks ago.

Emap Metro, whose stable included Q, Select, and Mixmag, has merged with radio and online projects to become Emap Performance Network. In March, Jerry Perkins, managing director of six Emap music titles, announced his departure. There has been criticism that too much attention is being focused on radio and online projects.

Ultimately, each magazine has to find its own niche. Magazines such as Q have managed to maintain circulation by pulling in those who used to read the weeklies and want to stay in touch. Kids might not need music magazines the way they used to, and perhaps, as many older readers moan, "things just aren't the same any more." But it would have been tempting, but mistaken, to have written off the NME just before punk broke in 1976. So, all bets are off.