Though they live so far north in upstate New York that they're blocks away from being a Canadian band, the five-piece Gibson Brothers are this country's modern bellwethers of traditional bluegrass. To wit, they've won IBMA's sacred Entertainer of the Year prize two years in a row, including last month in Raleigh. With high, tight harmonies and unfairly precise playing, they are a captivating force. But they're not only concerned with ferocious picking sprees. Their tender-hearted latest, They Called It Music, hinges on a handful of slow originals that survey the exigencies of love and the assurance of faith. Sure, they're allegiant to the old craft, but the Gibsons participate in bluegrass's continuum by first learning it and then tacking on.