term for a "studio musician
," "session player
", or "sideman
" brought in to the studio help out with an artist's recording. Ringers are necessary because they can provide some talent that the band or artist lacks. It could be that a band member isn't skilled enough to pull off the parts that the producer wants him to play, and band doesn't want to waste studio
time practicing a complicated section over and over again, or maybe the producer wants to use some extra instrumentation
that the band members are not trained in.
Always highly trained, the ringer must be dependable and able to play in any style, key, and on any number of instruments. A stubborn ringer won't get many jobs, as he/she is almost always forced to play as the bandleader and/or producer wants him or her to play. Being forced to play whichever crap style is popular at the moment leaves ringers slightly bitter, but fairly well-paid.
Many talented artists have started out as studio musicians before convincing A&R men they were worthy of being recording artists of their own right. Jimmy Page and Eric Clapton are two legendary guitarists who at some point made their livings this way.
It's sometimes disturbing to think that maybe the cool guitar work on your favorite album wasn't done by the band's guitarist, but unfortunately the music industry would rather have you believe that the artist's work was fun and easy to do. In the age of MTV, magic, mystique, and a pretty face sells far more than academic virtuosity.