A subwoofer can make a room sound powerful.
It can also reveal loose panels, cabinet doors, light fittings, glass shelves, grilles, brackets and furniture in the room.
Subwoofer rattles should be found before the client hears them.
Bass moves the room
Low-frequency energy behaves differently from normal background music.
It can excite furniture, ceiling details, cabinet panels, loose screws, sliding doors, ornaments and hidden cavities. A room can look perfectly finished and still rattle when the cinema is used properly.
That is why subwoofer testing belongs in commissioning.
The fault may not be the subwoofer
Clients may assume a rattle means the speaker is faulty.
Often the subwoofer is simply exposing something else. A loose cabinet panel, cable, grille or fitting can vibrate at a particular frequency.
The technician needs to test the room, not only the equipment.
Hidden subwoofers need extra care
When a subwoofer is hidden inside furniture or cabinetry, airflow, vibration isolation and service access matter.
The installation may look clean, but the cabinet around it becomes part of the audio system. If that cabinet resonates, the client hears the furniture, not only the bass.
We cover this design issue in why hidden subwoofers need airflow, vibration and service planning.
Test at real levels
A quiet test is not enough.
The room should be tested at realistic listening levels with material that exercises the subwoofer properly. That does not mean abusing the system. It means confirming that the room behaves under normal cinema use.
DG Technologies treats rattles as part of commissioning
A premium cinema should not be handed over with distracting noises that have nothing to do with the soundtrack.
Finding rattles early is part of finishing the room properly.
The client should hear the film, not the cabinet.