Dick's Picks Volume 31 is a four-CD live album by the rock band the Grateful Dead. It was recorded on August 4 and 5, 1974 at the Philadelphia Civic Center in Philadelphia, Pennsylvania, and on August 6, 1974, at Roosevelt Stadium in Jersey City, New Jersey. It was released in March 2004.

The Wall of Sound was an enormous sound reinforcement system designed in 1973 specifically for the Grateful Dead's live performances. The largest concert sound system built at that time, the Wall of Sound fulfilled lead designer Owsley "Bear" Stanley's desire for a distortion-free sound system that could also serve as its own monitoring system. Due to its size, weight and resulting expense, the full WoS was only used from March to October of 1974.