Here is Donny's explanation.. I don't think I agree


" A Power singer and a Power single
Are terms used on the business for acts that can command a stage strongly taking the place of a full band with really strong vocals and harmonies..
And great entertainment qualities
and stage presence and can perform in
a large venue with 50-400 people easily.. "


So a "singer" performing with a karaoke track, can be a power single? And considered a better choice than an accomplished pianist.. Go figure