George Carroll, a Sarasota icon, is at the center of jazz in his adopted hometown. He is a survivor in a vortex marked by failing clubs, uncaring moneychangers and a musically uneducated, often indifferent public. Yet the 71-yearold, composer, vocalist, big band leader for more than 40 years in his native Boston and Sarasota, has experienced recent success on the national stage with well-received performances in New York and Boston. "I have no delusions about big-time engagements or the music business itself," Carroll said between sets at the Meadows Village Pub,, a Sarasota club where he plays to packed houses with his quartet and big band. "It's a tough racket, believe me. But sometimes I'm in awe of what I've accomplished, particularly during an era when clubs are closing right and left."