Audac WMM630 In-ceiling/Wall Back-Box for Flush Mount Ceiling SpeakersThe WMM630 is a speaker back box made out of medium density fibreboard (MDF) allowing installation for a wide variety of ceiling or in wall loudspeakers. It provides an ideal environment for the installed speakers while reducing the radiation of sound to adjacent rooms. The dimensions of 345 x 545 x 150 mm allow it being placed in between a wide variation of wall studs or ceiling beams. It features an internal volume of 21 litres and comes with a pre