The best thing about Zeitgeist is that Corgan is back to what he does best: hard-rock architecture. His wall-of-guitars overdubs are exhilarating in their details: the harmonized squeals in “7 Shades of Black”; the creeping buzz of “Tarantula”; the long, howling solo, sinking in echo, in “United States.” The Pumpkins were never more exciting in the Nineties than when Corgan unleashed his inner Tony Iommi all over his inner Robert Smith. That is what happens on Zeitgeist, which makes it a strong new start for Corgan and Chamberlin, no matter what they call themselves. DAVID FRICKE