Amy Ray and Emily Saliers are a unit much greater than its parts. Blending their voices into a single, finely tuned instrument called the Indigo Girls, Ray and Saliers shook Franklin & Marshall College's Mayser Gymnasium with their own brand of folksy rock.

The Indigo Girls scorn the synthesized sounds and electric flash of so many live performers. Instead, they rely on their voices, which soar in exquisite harmony, and the simple sounds of their own guitars. Far too many performers suffer under the unforgiving scrutiny of a live audience. Vocals which sound perfect after numerous studio takes often sound far worse without the benefit of digital tracking. The Indigo Girls needn't fear, however. They wield their voices with studio precision, never faltering and never going flat.

They paused only once, after an abrupt bass rumble from one of their speakers shook their stage. Later, Ray continued a faultless solo rendition of "Romeo and Juliet" despite a broken guitar string. The duo sings with a kind of simple strength and naked emotion that shows they feel their music -- they don't just play it. And the crowd grew wilder with each "Thanks, y'all" -- a standard fixture after each tune. The play with no pretension but incredible diversity, melodies lilting on "Love Will Come" or rocking down and dirty with "Chickenman." Sometimes one singer will provide a perfect counterpoint for the other. On another song, they switch. But on most, they were equal partners in towering, sinuous harmonies that bend and yield to the other as they share center stage.

Although they shine as a combined pair, the duo from Georgia has distinctive, individual talents. Ray sings with a low and melodious voice, dripping honey as she stomps, dances, shakes her head and provides fast and furious rhythm on her guitar. Saliers sings higher, soaring with feeling, but her fingers fly to produce intricate melodies.

The band's loyal following rocked gladly to familiar tunes like "Joking," "Land of Canaan" and "Galileo." They also gave the crowd its shot at the spotlight. Bringing up the house lights and stepping away from their microphones, the girls let 2,500 fans carry the last chorus of "Prince of Darkness." The majority of the audience knew every word. Oddly lacking in the concert, however, was "Closer to Fine," their groundbreaking single from 1989 which rocketed them into the public eye.

The concert concluded a year-long tour following the release of their third major-label album, Rites of Passage. Ray said the tour is leading into a "very long break" for the pair. "Next time you see us, we'll have a new record out," she promised.

The Indigo Girls followed a little-known opening band led by James Hall. Hall, however, sang without distinction and played a trumpet with the grace of a car horn. He earned hoots when he stripped down to nylons, and most of the audience never got into the pounding that served for a melody line. The band had nothing going for it but volume, and was earning loud boos from the restless crowd until Saliers and Ray joined Hall on stage for the last two songs.

When the Indigo Girls later retook the stage with only their voices, their acoustic guitars and basswork provided by former B-52 Sara Lee, they easily overpowered the electric noise that preceded them.

[ by Tom Knapp ]