Now that anyone with a laptop can make decently epic soundscapes, how will Sigur Rós keep its lead? On "Valtari," it does it by using all its usual tricks, but in even more evocative and expert ways. On "Valtari" it's back to the essentials: oceanic buildups, flickers of treated orchestras and falsetto vocal lines that yank heartstrings, even though you know exactly when they're coming. Santa Barbara Bowl, 1122 N. Milpas St., Santa Barbara. 7 p.m. Fri. $40.50-$55.50. sbbowl.com.