This extra-depth torsion enclosure with acoustic fiberglass lining extends quality and enhances performance of 8 inch dia. commercial and professional speakers. The increased volume of this enclosure extends the low frequency response by improving acoustic loading. Backbox inner surfaces are undercoated to prevent metallic resonance in the higher end of the frequency spectrum and lined with 1-1/2 inch (38 mm) thick high density fiberglass (1-1/2 lbs. per cu.ft.) This round unit is designed for recessed mounting. Enclosure is constructed of heavy-gauge CRS and includes four conveniently located combination conduit knock-outs to facilitate installation. Model is finished in rust-preventive, textured black coating.