SANTA CLARA, Calif. (AP)-Linebacker Tavares Gooden has been known to get down and start strumming an air guitar before practice.From Bruce Springsteen to Bob Seger, from country to hip hop, and rap, rock and R&B, the San Francisco 49ers are getting nearly as much variety through their impressive sound system during workouts as they are in coach Jim Harbaugh's creative offense.No doubt these playoff-bound Niners are feelin' groovy.And it sure beats the crowd noise that gets pumped into a lot of practices around the NFL to prepare teams for loud, hostile road environments."We just jam," defensive line coach Jim Tomsula …