Anyone who has heard Evil Urges, the most recent My Morning Jacket release, must be aware that this band's sound is changing dramatically. The new album features short, mellow, radio-friendly songs with simpler structures and fewer frills than even the most pared-down pop of their prior records. The album also features several tracks that represent an odd foray into new musical territory for My Morning Jacket-places as varied and surprising as disco and metal. To fans of their earlier material, Evil Urges amounts to something of a controversy. The more listenable tracks feel tired and less inspired than almost anything off of Z or It Still Moves, while the more offbeat genre explorations are miscalculated and blundering. Thus, through their late reinvention, the band appears to be moving in two directions at the same time; one is a boring, sleepy and supremely marketable imitation of what fans found enjoyable in earlier MMJ while the other is hard to engage on account of its stubborn divergence from the path the band has so successfully blazed on earlier records. The upshot of all of this is a doubly jarring experience of hearing a lame yet euphonious alternative-pop song by MMJ on the soft-rock station in the dentist's office, only to be bewildered by their more bizarre, highly inaccessible attempts to branch out. It seems as if, sensing an opportunity for increased mainstream success, they wanted to dumb down their sound but then took an opposite tack and decided to do something "interesting" for their faithful listeners.

In trying to have it both ways, though, MMJ seem to have failed at the latter objective-at least based on the show they played Saturday night at the Bank of America Pavilion. The crowd itself demonstrated a change in MMJ's fan base, with attendees being less of the neo-hippie, hillbilly-hip and indie types I was used to seeing at previous MMJ concerts. Instead, the show was littered with Celtics hats, college T-shirts and overflowing cups of beer-in short, the sort of concertgoers one would expect to find at a Dave Matthews Band show. Tellingly, the overwhelming response to tunes off the new album, such as "I'm Amazed," felt disproportionate to the energy in the music, especially when judged against older material performed over the course of the evening. It was obvious that the crowd was far less familiar with anything predating Evil Urges.

Nevertheless, MMJ did play quite a few of their best live numbers off albums ranging from The Tennessee Fire to Z, shining especially on the Who sound-alike "Gideon," which was summarily overshadowed by the twin-guitar climax on the rocker "Lay Low." Regrettably, there were several unforgivable flaws in the sound setup; the bass was mixed far too loudly and would often drown out the finer points in the music. But the best songs were invariably enjoyable because they managed to convey the excitement that was so glaringly absent in the newer material.

The members of MMJ seemed cognizant of their former successes and (relatively) recent shortcomings, as they opened with "Mahgeetah," a classic from 2003's It Still Moves, and they wrapped up their encore with the raucous, heavy anthem "One Big Holiday" from the same album. And at no moment was cape-sporting frontman Jim James more engaged with the music than when he went down to his knees and began wailing the ending notes to "Wordless Chorus," a song from Z. These moments can reassure fans that, despite this spring's missteps, MMJ have not forgotten what they do best. Hopefully, we can expect them to get back on the right track with their next album.