Old sound—A sound that you remember from a long time ago. … New Sound—A sound that you have never made before. … Borrowed sound—A sound that you borrow from someone else. … Blue sound—A sound that is blue for you. … First listen inwardly to find your sound to be expressed vocally. Voice each kind of sound—old, new, borrowed, blue—from one to three times within a time frame of about five minutes. Pace yourself by listening to every one and everything.

Pauline Oliveros, Deep Listening, loc. 367