Wearing a goofy cap shaped like the head of a fuzzy brown bear, an only slightly less fuzzy Jim James grinned broadly at the crowd gathered downstairs at the Middle East Saturday night for My Morning Jacket’s headlining performance. "Man, we gotta play this place more often," said the shaggy-maned singer/guitarist of the Louisville band, astonished at the roar of approval that greeted the start of what would be an electrifying 90-minute set. "You guys are ferocious!"

The same could be said of My Morning Jacket, who blazed headlong with joy and abandon through the best parts of their 1999 debut, The Tennessee Fire, and the more recent follow-up, 2001’s At Dawn (both Darla), and gave the crowd a preview of some fresher material currently slated for Still Moves, the band’s forthcoming major-label debut for ATO/RCA. Indeed, the two-month tour that brought My Morning Jacket to the Middle East seems aimed both to showcase and to sharpen a batch of newer songs that are likely to constitute a healthy part of the group’s live set for some time to come.

The good news is that the new material gives no indication that the fivesome have tailored their sound to suit the suits at RCA. If anything, it marks a natural progression in the band’s retro-tinged, chamber-pop æsthetic: the guitar riffs are bigger, the backbeats harder, but there’s been no reduction in the telltale oceans of reverb that have been submerging and reconstituting James’s arresting howl since the group’s first recordings.

That voice was front and center as the show opened on a blistering note with one of the new tunes, the raunchy-licked "Dance Floors." It radiated from amid the wallop of muscular drums and driving rhythm guitar and bass, cutting through the noisy roar of James’s cousin Johnny Quaid’s stinging lead guitar with a shimmering melody. The overall effect was that of early-’70s Stones/Faces raucous roll, with a sprinkling of James Gang stoner swagger for extra crunch.

The rest of the set showcased My Morning Jacket’s versatility, as the band downshifted into the gritty cowboy folk of At Dawn’s "Lowdown" and built up to epic extended instrumental jams on the harder-rocking "Heartbreakin’ Man" (from The Tennessee Fire) and "The Way That He Sings" (from At Dawn), making full use not only of Quaid’s sinewy guitar playing but also of keyboardist Danny Cash’s organ tones and synth textures. These weren’t aimless jam-band excursions — they were the kind of crowd-pleasing, crescendo-building refrains that get borrowed from classic rockers like the Stones and Faces, but done in a style that My Morning Jacket could easily call their own.