Rattles are the most irritating fault in car audio and the easiest to find systematically. The trick is to excite one frequency at a time rather than playing music and guessing.
The method
Play a slow sine sweep from 20 to 200 Hz at moderate volume, on repeat. Sit still and listen for where each buzz appears in the sweep, then have a helper press firmly on candidate panels while the sweep runs. When the noise stops, you have found it.
The usual suspects, in order
- Number plate and its mounting frame
- Boot lid skin and the light clusters set into it
- Parcel shelf and anything resting on it
- Door cards where a clip is missing or broken
- Loose trim around the amplifier or subwoofer enclosure
- Objects in door pockets and the glovebox
Fixing what you find
Panel against panel is fixed with closed-cell foam tape between them. A panel ringing on its own is fixed with a damping tile in the centre of the flexing area. A loose fixing is fixed by tightening it, and a broken clip by replacing it rather than by adding tape.
Check the enclosure itself
A subwoofer box that buzzes is usually either a loose mounting screw on the driver or a leaking seal. Run a bead of sealant inside the joints and torque the driver screws evenly in a star pattern rather than one after another around the circle.
If the noise is electrical rather than mechanical, our whine guide covers that instead.
