Her brother formed the Richard Carpenter Trio in 1965. Karen played the drums. Richard played the piano, and a friend named Wes Jacobs played the electric bass. They played jazz music at clubs in Hollywood. They entered the Battle of the Bands contest at the Hollywood Bowl in 1966. The Richard Carpenter Trio played "The Girl From Ipanema" and "Iced Tea," a song composed by Richard Carpenter. They won the Battle of the Bands that year. Afterwards, they signed with RCA Records, but the RCA thought their music would not sell, so RCA let them go. The Richard Carpenter Trio made one last TV appearance on "Your All American College Show" in 1968, where they played "Dancing in the Street." Karen had a great drum solo. They won the "Your All American College Show" contest, too.