BMW 428i xDrive Gran Coupe Rear Door Panel Speaker Size
The BMW 428i xDrive Gran Coupe rear door panel accommodates a 1 inch speaker size and 4 inch speakers. Compatible types for the audio system include tweeter and midrange units. These specifications cover the 2015 to 2016 model years.
| Year | Type | Size (inch) |
|---|---|---|
| 2016 | Tweeter | 1 |
| 2016 | Midrange | 4 |
| 2015 | Tweeter | 1 |
| 2015 | Midrange | 4 |
Speaker Types
| Type | Description |
|---|---|
| Tweeter | A small driver built for high frequencies, typically from about 2,000 Hz to 20,000 Hz. It adds treble detail and clarity and is usually mounted near ear level or aimed at the listener. |
| 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 in the BMW 428i xDrive Gran Coupe accommodates 2 distinct speaker sizes across both listed model years, with each size corresponding to a dedicated speaker type.
- Door panel installations are typically surface-mounted or recessed into a molded cavity within the door card, with depth clearance and baffle geometry determined by the panel's inner structure.
- The 1-inch driver size in the rear door panel position is designated exclusively for tweeter use, a pairing consistent with the compact diaphragm area required to reproduce high-frequency content, generally spanning from approximately 2,000 Hz to 20,000 Hz.
- Tweeters mounted in rear door panels contribute to the high-frequency component of the rear soundstage, with the door position placing the driver at a relatively low height relative to seated occupants.
- The 4-inch driver size in the rear door panel is designated for midrange use, a size associated with reproducing mid-frequency content, generally from approximately 300 Hz to 5,000 Hz, where vocal intelligibility and instrumental presence are concentrated.
- A 4-inch midrange driver in a door panel relies on the door cavity to function as an acoustic enclosure, with the internal volume and sealing quality of the door affecting low-midrange output and resonance behavior.
- The rear door panel's placement behind seated occupants means midrange and high-frequency drivers at this location contribute primarily to ambience and spatial fill rather than direct frontal imaging.
- The simultaneous presence of a 1-inch tweeter and a 4-inch midrange in the BMW 428i xDrive Gran Coupe rear door panel indicates a multi-driver configuration at that location, with frequency responsibilities divided between the 2 drivers.
- In a multi-driver door panel arrangement, the physical separation between the tweeter and midrange mounting points within the door card can influence time alignment between the 2 frequency bands at the listening position.
- The 4-inch diameter constrains the driver's low-frequency extension, making the midrange designation acoustically appropriate, as smaller cone areas generate less air displacement and reduced output below the midrange band.