Hempispheres sends Sleep’s new trio into a looser corner of their stoner-doom universe, where Al Cisneros’s bass-led chants, Bubba Dupree’s wiry fuzz guitar and Dale Crover’s rolling drums stretch five tracks into heavy psychedelic motion. Cosmic travel, cannabis mythology and an industrial invasion move through the record like a smoke signal, while the leaner guitar tone and agile grooves give the old Iommic weight a…