Over the past 20 years, Aimee Mann Has been a lot of things-from Til Tuesday pop star to major label poster child to unlikely Oscar nominee. But, one thing she’s never been is “loose.” The songwriter’s records have become increasingly pristine statements, each note, each lyric falling more and more perfectly into place.

Her most recent release, The Forgotten Arm, was recorded mostly live-in-the-studio, but it’s hardly a ramshackle affair. The record owes more to the slick ‘70s pop of Steely Dan and Elton John than, say, Neil Young and Crazy Horse. Her live shows have followed suit, as Mann and her consummately professional backing group have always played note-perfect renditions of her songs, making for enjoyable, if not quite life-altering performances.

Of course, Mann’s current tour (which kicked off last weekend in Boulder) seems to be an attempt to take her live modus operandi in the opposite direction. Playing in a stripped-down acoustic trio, the songwriter’s performance was warmer and more playful than her appearance last summer. It would be a stretch to call it a “loose” show, but there were plenty of welcome chinks in Mann’s perfectionist armor.

When she sat down at the baby grand to play Bachelor No. 2‘s lovely “Nothing Is Good Enough”, she announced to the crowd, “I can’t really play piano, so expect some mistakes.” Sure enough, Mann flubbed most of the second verse, but, rather than off-putting, the result was endearingly amateurish. At the end of the song, she raised her arms in mock triumph.

Though the spotless, Beatles-esque production quality of Mann’s studio recordings is part of their appeal, her songs work well in this more skeletal form. Selections from the acclaimed Magnolia soundtrack (which, judging from audience response, remains her most popular work) sounded especially powerful, as the Oscar-nominated “Save Me” and “Wise Up” were each given satisfyingly uncluttered airings. Mann revealed an oft-forgotten tidbit about the latter song: Magnolia was not its first soundtrack appearance. “This song was originally in Jerry Maguire,” she said sheepishly. “It was played when, I don’t know, Tom Cruise gets really fucking sad or something.” This offhand remark earned her the biggest laugh of the night.

Since Mann spent most of 2005 playing large chunks of The Forgotten Arm, she seemed content to only share a handful of tunes from the album this time around, including a slower, more mournful “Going Through The Motions” and the elegiac piano-based “That’s How I Knew The Story Would Break My Heart”. During these songs, the evocative, Grammy-nominated artwork from the album’s liners was projected on a screen behind the players, providing a visual counterpoint to Mann’s finely rendered character portraits.

From the very beginning, Mann’s always had her eye on the darker side of the human spectrum-addiction, co-dependency and depression are her favorite lyrical topics—but onstage at the Boulder Theatre, looking fairly ageless, Mann didn’t bring her audience into some deep, inescapable funk. Her subject matter may not deal with winners, but as her career progresses, she’s looking more and more like one every day.