THE AMERICAN classical music composer Samuel Barber (1910-1981) grew up in wealthy suburban Philadelphia, part of a music-loving family that included his aunt, Metropolitan Opera star contralto Louise Homer, and her husband Sydney, a minor composer. As a result, young Sam was able to meet and move in the world of the major figures in the East Coast classical music scene at an age when most music students would have just been looking on in awe from afar.