Bass reinforcement built into a plaster ceiling

Bass in a ceiling, a question of mass

A bass reinforcement moves far more air than a blade and weighs more. Building it into a plaster ceiling is therefore as much a structural matter as an acoustic one, and the point is dealt with alongside the framework before anything else.

Fixing

It is carried by the load bearing structure and not by the facing. A plasterboard carries its own weight and that of a finish, not the load of an element vibrating continuously.

Structural transmission

Low frequencies travel well through materials. A reinforcement rigidly fixed to a framework passes part of its energy into the floor above, and that point concerns the neighbour as much as the listener.

Decoupling

It is provided for at assembly. A flexible arrangement between the element and the structure reduces transmission without harming the radiation into the room, and it is the usual answer to this kind of problem.

The position in the ceiling

It matters little for localisation, because low frequencies cannot be localised. It matters a great deal for the resonances of the room, and moving it a few tens of centimetres changes the response in the bass.

What must be provided for

Access. A bass reinforcement is the most mechanically stressed element of the installation, and planning how it will be reached avoids opening a finished ceiling in ten years.

Plaster integration is described on the dedicated page, and home cinema on its own.