AUDAC WMM450

The WMM450 is AUDAC's fire-rated metal back box for flush-mount ceiling and wall speakers. A back box does two jobs at once: it gives the driver a sealed 15-litre volume to work against instead of the whole ceiling void, and it restores the fire compartmentation that cutting a speaker hole in a rated ceiling destroyed.

It is powder-coated steel, lined with acoustical damping wool, and measures 446 x 455 x 127 mm. Mounting slots take it onto supporting beams at 406 mm (16 inch) centres, in either horizontal or vertical orientation, and knock-out holes accept a cable gland so the cable entry stays airtight - which matters, because a leaking back box is an unsealed enclosure.