Dinosaur Jr. are no longer the volatile squad of twentysomething musicians anymore. Their individual personalities no longer conflict, cooler heads have prevailed, and they're back on the road and in the studio. Over twenty years after they started out as band, Dinosaur Jr. remain rocking in the free world. Both guitarist J Mascis and bassist Lou Barlow still have full heads of hair, and their musical output the past few years has been ineffable. Lucky for us, they're still willing to crank out live performances, and last night they were generous enough to have a tour stop in Santa Ana at the Observatory.