Constitution Hall housed an embarrassment of riches last night as two of the greatest singers in American music took the stage: first Ray Charles, then Aretha Franklin. Moreover, they both were in grand form as they used their gospel training to transform their rhythm & blues hits into transcendent moments of vocal art.

Notoriously moody and erratic on stage, the 40-year-old Franklin was in good spirits last night and sang as spectacularly as she ever has. As she whooped and testified her way through the up-tempo tunes, she shimmied and twisted in her glittering white gown.

On the ballads, she closed her eyes and let unearthly cries of passion escape between lines. Backed by an unusually tight 18-member road band, she extended songs like "It's Your Thing" and "Ain't No Way" into open-ended finishes in which her instincts took over and she improvised call-and-response shouts. The evening's highlight was a magnificent version of "I Want to Make It Up to You," which began with a wordless moan, built into a swooning plea and climaxed with gospel wails of ecstasy.

Despite his inconsistency on records, 52-year-old Ray Charles still sounds fabulous on stage. Clad in a gold dinner jacket and rocking back and forth on his piano bench, Charles toyed with his phrasing to build a tension between the vocals and the precise 17-piece Ray Charles Orchestra. Then he would release that tension by soaring across octaves for a falsetto squeal of joy or a bass chuckle of satisfaction.

In addition to his familiar hits, Charles displayed his versatility by tackling several country and show music numbers. He transformed the "good ol' boy" monologue of "Three-Four Time" with his full, grainy tone that swelled with pleasure. Charles' highlight was Mercer & Arlen's "Come Rain or Come Shine," which he sings in the movie "The King of Comedy." He built this tale of anticipated love from simmering hope to boiling exaltation, until he was holding single syllables across measures and through every imaginable vocal inflection.