Coldplay are currently holed up in a studio in northern London, trying to hammer out the details for their still-untitled fourth album, due out in May. On a white board, three band members have posted radically different proposed track listings for the album. Chris Martin has withheld his, hoping to lobby his colleagues a little while longer. "I heard a Bono quote once that said 'Bands shouldn't break up over money, they should break up over track listing,' " he says. "Nothing could be more pertinent at this point."

To record their fourth album, the band hired legendary producer Brian Eno and pointedly tried to remove all outside influences. "We felt like the first three albums were a trilogy, and we finished that," says guitarist Johnny Buckland. "So we wanted to do something different." The band let Rolling Stone hear the songs they're working on, and most are refreshingly, bracingly different from Coldplay hits like "Clocks" and "Speed of Sound."

Several tracks are considerably rougher around the edges, with distorted guitars and more prominent percussion. The lyrics are darker, dealing with recurring themes of death and loneliness. And on several songs, Martin extends his vocal palette considerably beyond the falsetto that has largely defined him, exhibiting a lower, sexier mode that feels more personal and real. "Whether or not it's good, we certainly started to use more colors," says Martin. "It's impossible to please everybody, and it took us a while to learn that. It's just the freedom to say, 'Everyone might not like this. We're into it at the moment, so let's just get it done.' "

The band explored in a variety of sonic directions, something they attribute to Eno's encouragement. "He's just not judgmental, it's very refreshing," says Martin. Buckland adds, "It wasn't so much that he brings like a sound or something to it. He brings lots of ideas about everything, even down to like how we structured our day." His suggestion? "Take lots of breaks."

Of course, the band is still hammering away at that track listing, but here's a guide to several of the songs likely to end up on the album: