Meet John Dough

If you're wondering how Mayer got off the next-Jonny Lang career track and on to ''Squares''' pop songcraft -- with its largely acoustic, no-frills fretwork -- blame the six months he spent at Boston's Berklee College of Music, a semester's worth of muso aversion therapy. '''Room for Squares' was a response to going to these clinics and literally falling asleep at the loudest, fastest guitar playing in the world.'' After this exercise in trying to craft a ''shamelessly melodic'' freshman effort, he does want to re-up the guitar ante on his next album: ''I'm learning still how to take the Dave Matthews/Sting/Ben Folds/Jeff Buckley/Elton John/Paul Simon/Billy Joel thing and [mesh it with] the Hendrix/Stevie Ray/Charlie Hunter/Clapton thing.''

Part of that pendulum swing back toward electric guitar may stem from the overabundance of female faces we'll see at the lip of the stage tonight. Chicks dig him. ''I really don't want to be a hunk,'' he says. ''I don't want to be Sensitive Hunk Guy. That's just a little fear of mine. But I think women can relate to the lyric side more. I know the guys are waiting for all the sappy songs too, but they have a front, which is the guitar playing.''

Not that the next batch of songs will be unemotional. A new tune, ''Split Screen Love,'' is inspired by a fresh breakup. ''I enjoy writing songs right now, because I'm stinging. I can write from a straight-up point of rawness that I didn't have at the time I wrote 'Room for Squares.' I don't usually throw my love around. I'm not a serial lover. Which is why I give myself such permission, when I finally do, like 'Splurge, Johnny, you know you don't do this all the time -- go for broke!' So you do, and well, then, it goes broke,'' he says, laughing.

Oh, all right, it IS Jennifer Love Hewitt we're talking about. The relationship between the self-described dork and his TV-star sweetheart went public when paparazzi shots of the couple appeared in People and Rolling Stone...just days after they split up. Damn right, he's got the blues. ''It was a strange little detour that I took for a minute,'' says Mayer of the short-lived affair. ''Hopefully the people who listen to my music can relate to it in their life -- save for the People magazine part. It's really just an all-American, boy meets girl, check it out, fall madly in love, go overboard to the point of no return, and then do your best to get over it story. It sucks. Because the idea of it was fantastic. It just didn't work. And I hate that. Because I would've been loyal. And I was, but it just didn't.... I hope I'm not being too cryptic. It's not anything [other] than two people being very different. And hopefully I can go through it and not be cheesy about it and not be the guy in People, but just the normal heavyhearted guy.''

The sky should be crying, but the downpour over Detroit is abating as Mayer takes the stage. The dampened crowd of 8,000 will remain on its feet for the entirety of his hour-and- 40-minute set -- even though none of these songs are exactly ''Detroit Rock City.'' ''I suck at rocking,'' Mayer admits. ''I couldn't make a fist while I play guitar to save my life. But what I want to be better at is making people whimper. I want to make my next record impossible to listen to if you've just broken up with somebody -- to make songs so volatile that people either love it or go, 'Turn it off. Don't do it to me. Not now!''' If he can pull that off, Mayer may just have lightning in a jewel case.