BMW X4 Rear Door Panel Speaker Size
The BMW X4 rear door panel accommodates a 1 inch speaker size and 4 inch speakers. Compatible types for these locations include tweeters and midrange units. The specifications cover the 2015 to 2018 model years.
| Year | Type | Size (inch) |
|---|---|---|
| 2018 | Tweeter | 1 |
| 2018 | Midrange | 4 |
| 2017 | Tweeter | 1 |
| 2017 | Midrange | 4 |
| 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 BMW X4 rear door panel accommodates 2 distinct speaker sizes across all listed model years: 1 inch and 4 inch.
- Rear door panels are vertical, trim-integrated surfaces positioned within the vehicle's cabin along the side walls behind the front seats, placing speakers at roughly seat-height level relative to rear passengers.
- A 4 inch midrange driver in a rear door panel operates across the mid frequencies, generally spanning roughly 300 Hz to 5 kHz, reproducing vocals, instruments, and the core body of most audio content directed toward rear cabin occupants.
- The 4 inch diameter of the midrange units reflects a physical constraint common to rear door panels, where available mounting depth and surface area are more limited than in front doors, restricting cone size and consequently low-frequency extension.
- A 1 inch tweeter handles high-frequency content, typically from around 2 kHz upward, reproducing detail, air, and transient definition in the audio signal reaching the rear seating area.
- The BMW X4 rear door panel's 1 inch tweeter mounting position at door-panel height places high-frequency dispersion at a relatively low vertical angle, which affects the directional projection of treble toward rear passengers rather than a more elevated position.
- Tweeters of 1 inch diameter use a small diaphragm, which supports high-frequency reproduction and wide horizontal dispersion, a characteristic relevant to the side-mounted orientation of a door panel installation.
- The pairing of a 1 inch tweeter and a 4 inch midrange within the same rear door panel constitutes a 2-way speaker arrangement at that location, dividing the audible frequency spectrum between the 2 driver types.
- Door panel installations are subject to mechanical vibration from the door structure itself, which can affect the acoustic performance of both the 4 inch midrange and the 1 inch tweeter mounted within the panel.
- The midrange driver's placement inside a door panel means the cavity behind the cone is the internal door void rather than a sealed or ported enclosure, influencing the lower-frequency output and efficiency of the 4 inch driver.