Simply put, we recommend using Fire and acoustic hoods in all installations. The Hood will do 4 things:
It will maintain the fire integrity of your ceiling
It will reduce sound travel between floors and through the ceiling void
It will help with thermal leakage of the room
It will improve the sound output of your speaker.
The rule to follow is: Fire hoods are required if the ceiling speaker is installed in or adjacent to habitable rooms or within a location of access or escape.