Al Jarreau and Chaka Khan are very different singers: He's a refined jazz stylist, and she's a volcanic soul shouter. What they share became apparent at Merriweather Post Pavilion last night: Their vocal talents are far greater than the material they sing. For most of the evening, first Khan and then Jarreau lavished their considerable talents on the slightest of songs.

Khan actually had the best of it in the opening set, which was short enough to squeeze out most of her weaker material and ended with a flourish of hits. Sporting an enormous mane of purplish hair, Khan bounced about the stage with total abandon.

Jarreau may well be the best scat singer of his generation, but last night he pushed his jazz singing to the side so he could perform some of the most forgettable pop-soul material in the business. Typical was "I Am the Night," which began with Jarreau imitating all kinds of percussion in an inspired duet with the drummer before moving into the tedium of the perfunctory dance hit and then reemerging with an a cappella scat coda. Like Khan, he was backed by a top-flight band. Looking dapper in his double-buttoned shirt and dotted black pants, Jarreau charmed the crowd with his banter, but the evening's highlight was the urbane blues "Since I Fell for You"; he outwailed the saxophone.

-- Geoffrey Himes