Door Cavity Acoustics
Canonical Definition
Door cavity acoustics is the coupled behavior of the loudspeaker, door metal, carrier, access openings, trim panel, cavity air, absorbers, barriers, leaks, glass, seals, and exterior environment. The door is neither a simple sealed box nor an ideal infinite baffle.
Five Systems Occupy The Same Space
| System | What it changes |
|---|---|
| Acoustic | front/rear separation, cavity modes, absorption, leakage and trim radiation |
| Structural | panel modes, mounting stiffness, clip and fastener motion |
| Water | splash, condensation, drains, watershield and dry-side protection |
| Mechanical | glass, regulator, latch, rods, cables and service motion |
| Safety | side-impact structure, sensors, airbags and crash behavior |
Response Mechanisms
- A large access opening can reconnect front and rear radiation.
- The outer and inner metal can move and radiate.
- The door card can become a second panel or small coupled cavity.
- A cavity absorber can reduce some reflections or transmission but must survive moisture.
- A rigid cover can improve a boundary while creating water, service, or crash problems.
Measure One Change At A Time
- Record window, door, trim, seal, and opening state.
- Measure driver near field, trim radiation, and listening position.
- Change one opening, panel, absorber, seal, or mounting interface.
- Repeat with the same reference and level.
- Check nearby seats and the crossover region.
Water And Service Constraints
Materials inside the wet cavity must not hold water against metal, shed into drains, contact the regulator, or block inspection. Access covers should be removable where the latch, glass, wiring, or crash hardware requires service.