A vehicle audio structure includes a seat assembly mounted to a vehicle floor at a plurality of mounting locations, the seat assembly having a seat bottom spaced apart from the vehicle floor. The seat bottom has a bottom surface with a partially confined area defined between the vehicle floor and the bottom surface. An enclosure structure is located within the partially confined area under the seat assembly. The enclosure structure has an upper wall located adjacent to the bottom surface of the seat bottom, a first bottom wall section, a second bottom wall section, a third bottom wall section and a plurality of side wall sections that define an enclosed space within the enclosure structure. The first bottom wall section, the second bottom wall section and the third bottom wall section are spaced apart from the upper wall by differing vertical distances.