A trapezoidal-shaped acoustic absorber is designed for use in music recording studios. The absorber is configured in the shape of a right trapezoidal prism and has an internal transverse pegboard partition which divides the absorber into a plurality of chambers. Each of the chambers is lined with fiberglass sound insulation padding and is resonant to a different frequency. The unit as a whole is resonant to still another frequency. A plurality of the modules are assembled together to line the walls or ceiling of a room so as to render the room suitable for mixing and recording musical sounds. The modular units are portable and allow audio recording and mixing to be formed in virtually any room without the necessity for access to a specially designed recording studio.