Like any expert who's completed his chatty preamble and now addresses a favorite topic, Malcolm Middleton becomes really animated -- in a soft, dryly expressive way -- as he recalls his favorite bar. "We always thought it was the perfect place to go on a Monday," he sighs. "On Sunday, we'd go hang out at a local club -- and Monday is the day for a hug and a pint."

If this is a cure for what ails us, then, he acknowledges, there’s some impenetrable melancholy here too. "I think the darkness in our tracks is mostly me, actually," Middleton says of his longtime partnership with Moffat, who, onstage, does a fair impression of an alcohol evangelist, pint held high as he berates the crowd as to how he doesnae care. "Aidan’s really happy all the time," Middleton assures us, "while I’m probably more manic. But most of the tunes come to me when I’m sitting round my house, bored. That’s just how it works out. To be honest, I don’t plan it that way." He pins the band’s diverse span of styles partly to the recent addition of two new musicians, cello player Jenny Reeve and violinist Stacy Seivewright, and partly to his own experience working on his own for a while. "I released a solo album [5:14 Fluoxytine Seagull Alcohol John Nicotine] last year, and toured round Europe by myself, which was great for my confidence. Course, it’s really funny -- I made an acoustic album and Aidan went and made an electronic one [under the name Lucky Pierre]. That’s exactly what we each bring to the band."

In 2001, Arab Strap returned to contractual bliss with Chemikal Underground, which, as a fledgling label founded by The Delgados (who, incidentally, are playing the First Unitarian Church on Thursday), took on the boys in 1995. Their two-year departure to Go! Beat was, at the time, their risky move forward; by returning, Middleton acknowledges, the band had pulled in retreat. With the release of Monday at the Hug & Pint, Middleton says, they found they could even show the album in progress to The Delgados without giving up a shred of the creative independence that keeps them with the label. "We don’t usually do this, but Stewart the bass player [of The Delgados] came along one day to listen to stuff. He was impressed … " Occasionally, there’s the odd twinge at Chemikal Underground, when funding becomes an issue. "We had a terrible experience with Go! Beat but we took a lot of money off them, which was good because we were young."

"See, the problem with major labels is they’re businesses, and so the people there don’t care sometimes about the music; because The Delgados own Chemikal Underground, their interest is in keeping the label going by putting out good records." Fellow Chemikal Underground star Barry Burns from Mogwai takes a guest spot on Hug & Pint, along with Conor Oberst and Mike Mogis of Bright Eyes, who appear on "Flirt" and "Act of War."

No wonder Middleton’s relieved to be back in a phase where they have "the freedom to do what we want." The band’s planning technique, he explains, is nonexistent -- he won’t even admit to planning the unplannedness. He writes almost all the music while Moffat tinkers separately with lyrics. "Basically, no, I don’t usually hear lyrics until I get to the end of [writing] a tune." The addition of lyrics in the latter stages means they’re written much more as languid, run-on rhymes than neat, poppy assonances: "Aidan has pages and stuff, and he’ll not so much fit lyrics to the mood of the song but pick lyrics which go with actual space." Yes, it’s that unplanned -- "but it always seems to work. We’ve never had problems where the mood of the lyrics clash with the mood of the song."

For all that, there’s no bland, cookie-cutter sentiment here: Moffat’s monologues are still incisive, whether the balmy, surreptitious track, "The Clearing," (recorded with Isobel Campbell and Chris Geddes of Belle & Sebastian in 1996), or on "Love Detective" from 2001’s The Red Thread, a remembrance of rooting through a lover’s box of personal letters. ("If you’ve got nothing to hide, why hide it?" he accuses, as the track spirals away from what’s fair: It’s about did and didn’t, who, what and when.) Much of Moffat’s input relies on caustic effect to sear away at menial lies between lovers, at the filthy truths within awkward nightmares. And much of it -- most of it -- is plumb with his past experience: On the new album, "Loch Leven" (pronounced leavin’) recalls a weekend getaway to that lake ripped from his diaries: "Aidan went there with his girlfriend a couple of years ago, and I think that was the weekend where it all fell apart," Middleton concludes obliquely. "But he’s calmed down a lot since the early days. He doesn’t use, y’know … real names or anything."

Arab Strap’s most careful intention, it seems, is not to "self-censor" -- often, late in the process, Moffat will sing a line before stopping abruptly and asking "Can we say that?" Halfway through a six-week acoustic tour of the States supporting Bright Eyes, then, Middleton realizes they might have to watch what they say to frontman Conor Oberst’s 14-year-old fans: "We got in some trouble the other day in San Diego," after Aidan shouted a touch overexuberantly at the crowd. "A lot of them are there wondering who these hairy Scottish blokes are."

It seems this hairy Scottish bloke may not be so sure either. Besides his band’s return to its former label and Middleton’s increased songwriting confidence, he’s regressed to listening to the music he loved when he was 14, heavy metal. Worst of all, he’s starting to feel a wee bit "sick of Falkirk. They’ve built three pubs on my street, so it’s full of noisy drunk people all night. I can’t stand it!" If he can still rock to old Metallica and spends evenings giving pints of sweat onstage, he’s allowed to get a cuddle from the bar. Make his a double.

Arab Strap plays Mon., April 28, 7 p.m., $15, with Bright Eyes and Jesse Harris, The Trocadero, 1003 Arch St., 215-922-LIVE.