Ray Charles, just weeks away from turning 69, still loves to hit the road--he's in the midst of a tour that will have him giving 39 concerts in Europe and the United States in less than two months. However, at the start of his Sunday night show at Wolf Trap, it seemed Charles had gotten up on the wrong side of the piano stool. Just a few bars into his classic "Georgia on My Mind," he signaled his big band to stop so he could grumble about feedback of some sort, from either the monitors or the crowd. He continued to gripe that his vocals were miked too loud throughout "Mississippi Mud," and inside the Filene Center the words were coming through so muddily as to be barely audible.

But whatever ailed the legend--and the house PA--cleared up when he kicked into his first blues of the evening, Percy Mayfield's "Stranger in My Own Hometown." The voice everybody had come for rasped and ached at all the right moments and with enough force to overpower the 17-piece orchestra, and the fans and Charles got equal pleasure out of both the synthesized solo banged out on his electric keyboard and guitarist Brad Rabuchin's wailing single-note run. During the Leon Russell standard that followed, "A Song for You," Charles slapped his thighs with glee and danced wildly in his seat. He kept up the dancing and grinning, and reassured all in attendance of his greatness through the closer, "What'd I Say."

Even when Charles didn't appear happy, he looked robust and oh-so-cool in a vintage '70s ensemble that included a maroon tuxedo, light brown patent leather loafers and the hippest shades in show biz.

Saffire, the brassy blues trio founded in Fredericksburg, opened with a set of bawdy material that at times was so blue, as in smutty, as to make the crowd cringe.

CAPTION: Ray Charles, touring hard at 68.