premise: Backing vocalists sing with other backing instrumentalists.
hypothesis: Backing vocalists are singers who provide vocal harmony with the lead vocalist or other backing vocalists . In many rock and metal bands ( e.g. , the power trio ) , the musicians doing backup vocals also play instruments , such as guitar , electric bass , drums , or keyboards . In hardcore punk or rockabilly , other band members who play instruments may sing or shout backup vocals during the chorus ( refrain ) section of the songs .