In the late 1970s, Popol Vuh’s music really started to change. Their albums were less focused, more varied, with leader Florian Fricke embracing different tonalities. On Die Nacht Der Seele (Tantric Songs), this meant anything from clattering percussive miniatures (“Im Reich der Schatten”) to a number of pieces that invoked the chanting of Tibetan monks (“Mantram der Erdberunhrung”, the gloomy “Wanderer durch die Nacht”). When the usual, two-chord mantras for guitar and piano did appear, with Renate Knaup and Djong Yun back on vocals, they felt lighter, unmoored, spun from altogether more fragile matter. But the core of the thing — hypnotic repetition, to access the infinite — is still there. “Florian’s music makes you stoned when you sing it,” Knaup told artist and journalist Edwin Pouncey back in 1996, “the repetition makes you high.”