A case for a mobile device includes embodiments having a support, a base, a plurality of outer walls, a plenum, and a sound guide. The base has a surface parallel to the mounting plane, and the outer walls extend from the base toward the mounting plane. The outer walls and the base (together with one or more surfaces of the mobile device) define a plenum, which is configured to receive sound from a mobile device when the mobile device is mounted to the case. The sound guide diverts sound toward two or more of the outer walls or through a combination of one or more outer wall, the base, and a front surface of the case.