J Mascis (b. 1965) is an American musician and songwriter, probably best-known as the singer, guitarist, and songwriter for Dinosaur Jr., though he has also occasionally worked as a producer and film composer. Born Joseph Mascis on 10th December 1965 in Amherst, Massachusetts, United States, in the early 1980s he founded the short-lived hardcore group Deep Wound with his high school friends Lou Barlow and Scott Helland. He started out on drums, but moved to guitar when he went on to found Dinosaur Jr.