AS R&B HARMONY groups go, the Whispers are something of a curiosity. On the one hand, this Los Angeles- based quintet can handle the most complex vocal arrangements with ease, finessing close harmonies and delivering a sound so well blended that it seems almost to spring from a single throat. But where most harmony groups would balance that blend against a strong lead voice the way Levi Stubbs completes the Four Tops, the Whispers lead with Wallace (Scotty) Scott, whose polished, mellow baritone seems just another facet of the vocal arrangement.

Hand them the sort of song that benefits from a tightly woven sound, and they'll carry it the distance -- which is exactly what they do with "Contagious," the strongest song on their new album, "So Good." Produced by Reggie Calloway of the group Midnight Star, it's about as solidly constructed a e single as you're likely to hear, with the rhythm tracks, instrumental coloring and vocals meshing like well-oiled machinery. It's a precision performance, and one that shows off all the Whispers' strengths.

Unfortunately, the rest of "So Good" is oh, so mediocre. Divided, as the last two Whispers albums were, into sides designated "dancin' " and "romancin', " the former consists largely of cliches with a beat, while the latter is crippled by Scott's inability to distinguish himself as a soloist.

THE WHISPERS -- "So Good" (Solar 60356-1); appearing Sunday at 7 and 10:30 at the Warner Theater.