Because Aqualung is more a man than a band, fans can never be entirely sure what they'll get when Matt Hales plays live. In the past, he's arrived on-stage solo one week, and flanked by a 15-piece orchestra the next. On his current North American swing, the 35-year-old musician is in what he laughingly describes as "rock-pig mode", meaning that he's on the road with a stripped-down backing band that's not afraid to kick out the jams. He promises, though, that three months from now Aqualung will look and sound nothing like it does today.

"We're doing the big, headlining kind of thing with the band right now, but we're already planning to come back in a couple of months' time and do something very contrasting," Hales says, on the line from the city that Old Milwaukee made famous. "I'm not sure how it will work, but it will be something very much nonrock and less pig."

Even though they swing from spirit-of-Spiritualized orchestral opuses ("Cinderella") to keyboard-buoyed near-ballads ("Something to Believe In"), the tracks on Aqualung's latest, Memory Man, lend themselves well to whatever live configuration Hales is in the mood for. There's an easy explanation for that. The singer and multi-instrumentalist spent a good two years fine-tuning the songs on the road, shaping and reshaping them both as a solo artist and with a supporting cast.

"The songs begin with me and a piano, but with this new record they very swiftly went beyond that to something else, quite deliberately leaving their roots behind," he says. "What's going to be interesting with these songs is sort of reverse-engineering them, taking them back to the quiet versions that they started with. And I like that idea. I think that most songs can stand to be messed with more than people seem to want to."

What the singer is getting at in a roundabout way is that Aqualung is determined to move forward, which explains why Memory Man sounds so dramatically bigger and lusher than, and therefore different from, the project's more stripped-down and earthier albums, Aqualung and Strange and Beautiful. From the glitch-hop percussion squelches and subsonic bass bombs in the soft-focus rocker "Pressure Suit" to the acid-damaged guitars at the end of the slow-building sleeper "Black Hole", Hales has dramatically expanded his sonic palette. If you only know Aqualung from hearing "Strange and Beautiful (I'll Put a Spell on You)" in Volkswagen Beetle commercials, prepare for something grand.

"It took a while to find the right vocabulary for this record, particularly with the bigger moments," he admits. "It was like, 'How do we pull this off without resorting to archetypal rock moves?' The challenge was to do that without coming off as dumb."

Dumb is something that Hales is obviously not. In fact, he's smart enough to totally appreciate where he is with the shape-shifting beast that is Aqualung.

"I'm pleased to be in this very modest place–this particular position that we've carved out for ourselves," he says. "It's partly by virtue of being so old that I can't possibly be cool. That's fantastic because I'm totally off the hook."

Aqualung plays Richard's on Richards on Sunday (May 13).