An in-wall or ceiling speaker enclosure (10) having a predetermined air volume is provided, and includes a housing (22) designed to support a speaker assembly (18) between a pair of adjacent wall studs (12,14). The enclosure (10) also has an expandable air chamber (24) of predetermined volume operably coupled and in communication with housing (22). The enclosure (10) can be easily mounted within a pre-cut wall opening (32) of minimal size.