Mark Stuart and Vincent Walker both are known as what in their bands?
Mark Stuart (musician): Mark Allen Stuart (born April 14, 1968) is a Christian rock musician, singer and songwriter best known as the lead vocalist for the Christian rock band Audio Adrenaline during their original run from 1987 to 2006. Vincent Walker:  He replaced Maurer as the singer in an odd switching of roles, and continues with the band as frontman.
singer