Top Music to Listen to While High: A Perfect Circle | APC was formed in 1999 by TOOL vocalist Maynard James Keenan along with guitarist Billy Howerdel. They met in 1992 during a TOOL show, and three years later Keenan agreed to listen to Howerdel’s demos in his home. With the concept of APC already in his mind, Howerdel was actually looking for a female vocalist. When Keenan heard Howerdel’s music, he said that he could hear himself singing the songs. And so A Perfect Circle was born.