Though Derek Trucks and Susan Tedeschi base the band that bears their name in Jacksonville, Florida, the 12-piece ensemble deserves at least honorary Austinite status. As their marathon set at Bass Concert Hall attested on Friday night, their music encompasses the wide range of traditional American roots sounds that remain the cornerstone of Austin’s Live Music Capital reputation.


It’s not just that their lineup includes two local players, drummer J.J. Johnson and trumpeter Ephraim Owens. Or that they were savvy enough to weave in a deep cut from Willie Nelson’s catalog (the underrated ballad “Somebody Pick Up My Pieces” from 1998’s “Teatro”). Or that guitarist Trucks occasionally co-writes with former Austin great Doyle Bramhall II.


No, it’s more the way that their set can often sound like a night on the town in our city’s most revered and storied venues. At any given moment Friday night, you could have closed your eyes and imagined you were at Antone’s, with Marcia Ball onstage belting out soulful Deep South R&B. Or grooving at C-Boy’s with Jimmie Vaughan and Mike Flanigin as Tedeschi reached back to her 12-bar blues burner “Little by Little” from a pre-TTB solo album.


As Trucks and Tedeschi began the second set with an acoustic mini-set that included the Sippie-Wallace-via-Bonnie-Raitt classic “Women Be Wise,” it felt like swaying to Toni Price at a Continental Club happy-hour gig. When backup singer Mike Mattison stepped out front on the eloquent Derek & the Dominos cover “I Am Yours,” it was perhaps like catching Dominos member Bobby Whitlock at one of his regular Saxon Pub gigs. And as Owens took a sweet solo on Dr. John’s “I Walk on Guilded Splinters” in the encore, you could imagine him coaxing out those trumpet tones at Continental Gallery or Elephant Room gigs he plays when not on the road with TTB.


The magic of the Tedeschi Trucks Band is how they’ve managed to translate such grassroots-level styles into a large concert hall experience that rivals any contemporary touring act. Mixing songs from this year’s “Signs” full-length and “High & Mighty” EP with a few cuts from their three previous albums and an illuminating array of covers, the group thoroughly entertained a sold-out crowd with two hours and 40 minutes of joyously uplifting music.


Masters of dynamics, the band’s signature move is bringing things down to a near-hush in the middle of a song, then gradually building it back up again with layers of instrumentation and voices. When that worked best, as on the first-set closer “Idle Wind” and the second-set highlight “Midnight in Harlem,” it was transcendent.


Part of their dynamic ebb-and-flow is knowing just how to use a 12-piece ensemble to best serve the songs. Sometimes that means just six musicians onstage, or seven, or nine; the permutations varied throughout the evening. But every single player in this greater-than-the-sum-of-its-parts lineup makes it work.


Drummers Johnson and Tyler Greenwell anchor everything with skillful touch that’s often best appreciated when they’re laying back with exquisitely subtle support. Singers Mike Mattison, Alecia Chakour and Mark Rivers are essential supports to Tedeschi’s clarion voice on risers at stage left, with Mattison and Chakour sometimes carrying the lead. In front of them, saxophonist Kebbi Williams and trombonist Elizabeth Lea team with Owens to create a high-powered horn section that consistently pushes the band higher. At stage right are the group’s newest members: bassist Brandon Boone, tightly locked into Johnson and Greenwell’s rhythms, and keyboardist Gabe Dixon, ably filling the spot occupied by Kofi Burbridge after his death earlier this year following a 2017 heart attack.


The lone downside of Friday night’s show was that it eventually became almost too much of a good thing. The Austin show was unusual: Memphis band Southern Avenue, which had been opening shows for TTB elsewhere, played at Utopia Fest, opening things up for a full night of Tedeschi Trucks at Bass. The hourlong first set was just about perfect, but after a 35-minute intermission, they returned for another hour and 40 minutes that felt like overkill toward the end. Crowd energy that peaked with the splendid “Keep on Growing” and “Midnight in Harlem” flagged a little as the band charged down the home stretch with “Shame” and “Bound for Glory” plus a two-song, 20-minute, jam-heavy encore.


On the other hand, if you were there first and foremost for Trucks’ wondrously lyrical guitar solos, maybe that finale was the best part. Clearly a big part of TTB’s audience comes from the jam-band universe, drawn from Trucks’ roots in the Allman Brothers Band. But what’s ultimately so special about the group Tedeschi and Trucks have led for a decade now is that their music rises above any such genre limits. They’re a roots-music tour de force, and as the 2010s draw to a close, there’s a strong case to be made that they’ve been America’s best band of the decade.