In 1974, the Dead toured with the gargantuan “Wall of Sound” system designed by LSD chemist Owsley Stanley; partly due to the expense, they’d quit touring by year’s end. But on this era-epitomizing set, recorded at the University of Montana, they’re on point. Jerry Garcia‘s wah-wah and Keith Godchaux’s Fender Rhodes pull jams into Miles Davis free-funk territory; vocalist Donna Godchaux adds signature off-notes; and the slow stuff shines brightest. See the 48-minute “Weather Report Suite/Dark Star/China Doll,” a journey through ion-storming space, landing gently. Those piloting skills are still unmatched.