 trumpet, guitar, flute, violin, muted trumpet, harmonica) with his voice—which he teaches online and via "Singing Instruments" seminars—teaching summer camp for young vocalists, and adjudicating choral festivals around the world.He has worked with many professional vocal groups, including 98 Degrees, The Nylons and Boyz II Men.Helping groups get started has been a ongoing goal of his for 30 years, which he does by providing free advice, support and arrangements.