Geo Spectrum Rear Door Panel Speaker Size
The Geo Spectrum rear door panel accommodates a 4 inch speaker size. Midrange units are the compatible audio types for the system. These specifications cover the 1989 model year.
| Year | Type | Size (inch) |
|---|---|---|
| 1989 | Midrange | 4 |
Speaker Types
| Type | Description |
|---|---|
| Midrange | A driver for the middle of the audible range, typically from about 300 Hz to 5,000 Hz, where vocals and most instruments sit. It is often paired with a tweeter and a woofer. |
Additional Notes
- The rear door panel location positions speakers within the lower half of the door structure, placing the acoustic output closer to floor level than a dashboard or rear deck installation.
- Door panel mounting introduces a baffle effect from the door cavity itself, where the enclosed air volume behind the speaker cone interacts with low-to-mid frequency reproduction.
- A 4-inch driver in a door panel location has a physically limited cone area, which constrains the displacement of air needed to reproduce deep bass frequencies with significant output.
- The Geo Spectrum rear door panel accepts a 4-inch speaker size, and the midrange type designation confirms the driver is matched to the acoustic space rather than to full-range or low-frequency reproduction.
- Midrange drivers are designed to reproduce the frequency band roughly spanning 300 Hz to 5,000 Hz, which covers the core of human vocal intelligibility and most melodic instrument fundamentals.
- In a rear door panel location, a midrange driver contributes to the spatial fill of the listening environment by directing midband frequencies toward the vehicle's interior from a lateral position.
- The 4-inch cone diameter results in relatively high directional control at the upper end of the midrange band, meaning frequencies above approximately 3,000 Hz radiate in a narrower pattern from the door panel surface.
- Midrange drivers typically use a dome or cone design without a dedicated crossover component for bass extension, relying instead on the enclosure characteristics of the door cavity to manage rear-wave energy.
- Door panel installations generally require shallow mounting depth to avoid interference with window mechanisms and internal door hardware, a factor that influences the acceptable driver profile for a 4-inch midrange unit.