Substance Over Surface presents "Substance Tape: The Art of Rap."compilation mixtape consists of 15 new and unreleased tracks from various S.O.S artists and affiliates. . Side A presents a medium - high energy level, combined with the perfect amount of grittiness, word play, & confidence. It ends with a tempo that transitions well into the more mellow, conscious, and smokers tracks which make up Side B. Although the overall feel differs from Side A, it still boasts a nice bounce that will surely leave the listener with a memorable rap experience.