If one were to compare the four voices of the Manhattan Transfer to jazz instruments, founder Tim Hauser's mellow, supportive tenor would be Grover Washington Jr.'s tenor sax; Alan Paul's punchy, pop-ish high tenor would be David Sanborn's alto sax; Cheryl Bentyne's flashy, brassy soprano would be Maynard Ferguson's trumpet; and Janis Siegel's warm, expressive alto would be Art Farmer's fleugelhorn. In other words, they are the equivalent of a competent, enjoyable pop-jazz horn section, but they hardly qualify as jazz all-stars.

Last night at Wolf Trap's sold-out Filene Center, the four were at their best when they stuck to their new album's ambitious arrangements of jazz standards with Jon Hendricks' lyrics. The Manhattan Transfer blended into lush Four Freshmen harmonies on the Thad Jones' ballad "To You," and they swung convincingly on Count Basie's "Rambo." They were less successful at a doo-wop segment that included an elaborate street corner stage set; they sounded more like a Broadway cast than a real sidewalk quartet.

Siegel, with her precise phrasing and full tone, was easily the most satisfying singer. The least satisfying was Bentyne, whose annoying affectations highlighted the group's deplorable camp tendencies. The four singers were backed by a solid jazz quintet.