"The Rolls-Royce is to cars what the Aeolian-Skinner is to organs," says Charles Callahan, who will give the first of three recitals dedicated to the Church of the Epiphany's rebuilt organ. Today at 3 p.m., he will begin with Bach's "Passacaglia and Fugue in C Minor," a piece conductor Leopold Stokowski considered "the greatest instrumental work ever written."

Now repaired after being damaged in a 1983 fire, the organ has a new console, some specialized registers and four new sets of string-tone pipes that are larger than those in the Washington Cathedral. "We're really going to set a trend for a more eclectic instrument . . . we're even using the most up-to-date solid-state computer technology," Callahan says.

Believing that his "mission is to bring the organ into the mainstream of musical life," Callahan says that "on occasion" he even plays some Duke Ellington. Frustrated with this past quarter-century's organists, who have focused mainly on Baroque or Neo-Classical, Callahan says he is branching out by bringing back the romantic organ.

"Although the organ is the most mechanical musical instrument, I believe that it can be the most emotional one in the hands of a sensitive musician."