premise: Backing vocalists sing over the lead vocalist.
hypothesis: Backing vocalists are singers who provide vocal harmony with the lead vocalist or other backing vocalists . In some cases , a backing singer may sing alone as a lead-in to the main vocalist 's entry or to sing a counter-melody . In pop and country songs , backup vocalists may perform vocal harmony parts to support the lead vocalist . Beat Street (album) . It features high-profile guest backing vocalists , including the Eagles ' co-lead singer Timothy B. Schmit , Toto 's lead singer Bobby Kimball and Chicago 's lead singer Bill Champlin .