POP MUSIC REVIEW : Bigger Act, Less Substance, by Indigo Girls

The tour pairing the Indigo Girls with opener Matthew Sweet is a bit of a booking anomaly, with the feminist, neo-folkie orientation of the mood Indigo being in the sharpest possible contrast with Sweet’s dill-flavored, gleefully loud rock ‘n’ roll. The contrast in this twin-bill may have helped define the artists to their mutual advantage on Wednesday at the Greek Theatre.

Having survived many tours as a duo, the Indigo Girls are branching out a little and doing everything bigger this time--big light banks, big set, relatively big band. But even so they still manage to make do without an electric guitarist, though you might take a while to notice its absence with a definitive rock rhythm section on hand (drummer Jerry Marotta and bassist Sara Lee) and with veteran violinist Scarlet Rivera taking a lot of the solos that would traditionally fall to guitar.

Said band was unfortunately absent or underused for large parcels of the show. And left to their own quiet devices the Girls can get into precious trouble, evidenced by normally self-controlled Amy Ray’s overwrought solo reading of Dire Straits’ “Romeo and Juliet,� which sounded as if she’s been listening to too many Melissa Etheridge records.

On the other hand, the dynamic, full-group rendition of Dylan’s “Tangled Up in Blue� was a surprise highlight, turned downright anthemic without being turned to mush.

Sweet’s blistering, 45-minute opening salvo wasn’t for everyone, but most seemed to go for his Crazy Horse-style hard pop--long guitar solos and all--even before he brought the Indigos out to guest on Neil Young’s “Cortez the Killer.�