I’ve been listening to Wilco ever since 89X in Detroit started spinning “Box Full of Letters” in 1995, but even then I was an Uncle Tupelo hard-liner—as far as I was concerned, Jeff Tweedy’s new project was just a decent band with a couple good songs. In the intervening years Wilco has evolved, into a respected and somewhat auteurist rock group, then into a high-powered collective dabbling in fairly far-out experimentation while retaining enough mainstream appeal to fill huge venues. But until recently, my opinion hadn’t changed—decent band, couple good songs.

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But judging by their new concert film, Ashes of American Flags, for the past few years at least I should’ve been seeing them every chance I got. The 13 songs in Ashes, as well as the seven in the special features, were filmed on five nights of a 2008 tour, in Nashville, Mobile, New Orleans, Tulsa, and D.C. The consistently solid performances, which feel easygoing no matter how high the energy level, are all shot through with a wild improvisational streak that runs way hotter onstage than in the studio. In concert the songs become sprawling, massive things—the six main members are frequently assisted by a horn section—and wander far from their familiar arrangements.

Tweedy’s willingness to let his bandmates outshine him is a very good thing for Wilco. The stage is full of huge talents jostling for space, and they all sound better when he’s not trying to keep them under his thumb. It’s a quality Tweedy shares with great front men like Bruce Springsteen, Robbie Robertson, and Jerry Garcia, and the film often seems to be trying to play up such similarities—though it’s not clear whether the guys in Wilco are conscious of them. I’m pretty confident Tweedy knew that the Nudie suit he wore on two nights would remind people of Gram Parsons, but I doubt he thinks his role as the calm center of a musical storm is something that links Wilco to the Grateful Dead.

Everybody in the current incarnation seems to be getting along—unlike in the 2002 Wilco doc I Am Trying to Break Your Heart, which was captivating like a train wreck. That’s not to say there’s nothing interesting happening offstage. We get a look at Kotche with his beaten-up hands in a bowl of ice and Cline lying down with a cold pack under his neck; he says he’s giving himself whiplash by thrashing around onstage and that two of his vertebrae are fusing. But Tweedy’s backstage philosophizing is painfully self-serious—can we all agree that Bob Seger’s “Turn the Page” is the last word we need to hear from a musician on the road about on how tough it is to be a musician on the road? Ashes, perhaps inadvertently, makes a case for the concert film as a genre: sometimes you can learn more about a man by watching him play than you can by listening to him talk.