Even without the right song or the right instrumentation, Bobby King and Terry Evans can stir up a mighty soul storm reminiscent of Sam and Dave, and of James and Bobby Purify. The duo's show at the Birchmere Sunday night, however, was frequently compromised by a dinky, synthesizer-driven horn section and some dubious song choices.

The most conspicuous of the latter was "Rock Your Baby," the hopelessly unredeemable disco hit. But even some of the material from King and Evan's new album seemed unworthy of their talent and far inferior to the spirited and frequently passionate covers the duo performed of "Dark End of the Street," "When a Man Loves a Woman" and "Don't Let the Green Grass Fool You." On those songs and others, King's voice often soared into a fiery falsetto, Evans's resonant baritone added contrast and color, and the two voices merged in gritty, robust harmony. With the help of a sharp rhythm section and a slide guitarist, the duo occasionally evoked the spirit of its recordings with Ry Cooder as well.

The opening set by the William Clarke Blues Band was also short on tunes that truly stood out (and long on monologues), but the combination of Clarke's gruff voice, imposing harmonica and the band's punchy attack proved awfully potent just the same.