“I’m just going to show up and enjoy it,” says Jack DeJohnette, as Jazzstock’s second summer culminates with a 70th-birthday tribute concert to legendary drummer and bandleader at 7:30 p.m. Sunday, August 12 at the Bearsville Theatre. The headliner is Terri Lyne Carrington, the acclaimed drummer, bandleader, composer and record producer who was a student of DeJohnette’s and has played with Herbie Hancock, Esperanza Spalding and many others. Carrington, who teaches at the Berklee College of Music in Boston, won a Grammy this year for Best Jazz Vocal Album, The Mosaic Project: a unique tribute for a drummer. Teri Roiger, founder of Jazzstock along with her husband John Menegon, explained that the recording featured Carrington’s innovative arrangements for a diverse selection of vocalists.