Jazz Spectrum is a jazz oriented vocal quartet, 2 guys, 2 gals, backed by 3 horns, piano, bass & drums. Their book consists of big band swing music, beautiful ballads, some doo wop and "good time" 50's rock and roll. All the arrangements are original, written by Bob Zaun, leader. The group has been performing in Northern Illinois, Eastern Wisconsin and Michigan's UP since 1995.