BMW 428i xDrive Rear Speaker Size
The BMW 428i xDrive rear location accommodates a 1 inch speaker size and 4 inch speakers. Compatible types for the rear audio system include tweeter and midrange units. The specifications cover a range from 2014 to 2016.
| 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 xDrive accommodates a 2-speaker configuration per model year, consisting of a 1-inch tweeter and a 4-inch midrange driver installed together.
- A 1-inch tweeter at the rear position handles high-frequency reproduction, typically covering the range above 2,000 Hz, where transient detail and presence in vocals and upper harmonics are defined.
- The small physical diameter of a 1-inch tweeter results in a wide dispersion pattern at high frequencies, which at a rear location means high-frequency energy is distributed broadly across the cabin rather than directed narrowly toward a single listening position.
- A 4-inch midrange driver covers the vocal and upper-mid frequency band, generally from around 300 Hz to 5,000 Hz, reproducing the fundamental frequencies of human voice and many acoustic instruments.
- At a rear installation position, a 4-inch midrange driver lacks the cone surface area needed to move the air volume required for deep bass reproduction, placing the low-frequency floor of the rear stage at a point where a dedicated subwoofer or front woofers would need to supplement.
- The 4-inch diameter is a compact form factor, which is consistent with the spatially constrained mounting locations typical of rear deck or door configurations in a 4-series coupe body style.
- The pairing of a tweeter and a midrange driver in the same rear location indicates a component or coaxial arrangement where crossover filtering divides frequencies between the 2 drivers, allowing each driver to operate within its optimal frequency band.
- A tweeter's high-frequency directional behavior at the rear of the vehicle means placement angle and positioning relative to rear passengers and reflective surfaces affect how high-frequency content reaches forward-seated listeners.
- The BMW 428i xDrive rear speaker bay accommodates the same 1-inch and 4-inch size specifications consistently across the 2014, 2015, and 2016 model years, indicating dimensional continuity in the mounting location across that production span.
- A midrange driver at a rear location reinforces the sense of spaciousness and ambience in a stereo image by adding mid-frequency energy from behind the primary listening position.