BMW 428i Rear Speaker Size
The BMW 428i rear location accommodates a 1 inch speaker size and 4 inch speakers. Compatible types for the rear include tweeters and midrange units. The specifications cover the 2014 to 2016 range of years.
| Year | Type | Size (inch) |
|---|---|---|
| 2016 | Tweeter | 1 |
| 2016 | Midrange | 4 |
| 2015 | Tweeter | 1 |
| 2015 | Midrange | 4 |
| 2014 | Tweeter | 1 |
| 2014 | 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 speaker location in the BMW 428i accommodates a 2-driver configuration, pairing a 1-inch tweeter with a 4-inch midrange across all listed model years.
- A 1-inch tweeter in a rear cabin position handles high-frequency content, typically operating in the range of approximately 2,000 Hz to 20,000 Hz, reproducing detail such as upper harmonics and transient sounds.
- The small diaphragm area of a 1-inch driver is acoustically suited to high frequencies, where short wavelengths require minimal cone excursion and precise directional control.
- Rear placement of a tweeter introduces off-axis high-frequency dispersion toward the listening area, where sound arrives at the ears from behind or beside the seated occupants.
- A 4-inch midrange driver in the rear location covers the mid-frequency band, generally spanning approximately 300 Hz to 5,000 Hz, which encompasses the core presence range of most acoustic instruments and vocals.
- The 4-inch cone diameter provides sufficient surface area to move air efficiently at mid frequencies without the mass limitations that would reduce output at the upper end of the midrange band.
- In a rear installation, a 4-inch midrange contributes ambient fill and localization cues that extend the perceived soundstage beyond the front speakers.
- The BMW 428i rear location uses a dedicated midrange driver rather than a woofer or full-range unit, indicating the rear position is not responsible for low-frequency bass reproduction within the listed specifications.
- The combination of a 1-inch tweeter and a 4-inch midrange represents a split-driver arrangement, meaning each driver is optimized for a specific frequency band rather than a single driver covering the full audible range.
- Mounting a tweeter and a midrange in the same rear location requires that the installation space accommodate 2 separate driver cutouts or housings within the rear panel.