BMW Alpina B7L Rear Door Panel Speaker Size
The BMW Alpina B7L rear door panel accommodates a 1 inch speaker size and 4 inch speakers, supporting both unique speaker sizes across all listed years. Compatible types for these locations include tweeters and midrange units within the audio system. These specifications cover the 2013 to 2015 model range.
| Year | Type | Size (inch) |
|---|---|---|
| 2015 | Tweeter | 1 |
| 2015 | Midrange | 4 |
| 2014 | Tweeter | 1 |
| 2014 | Midrange | 4 |
| 2013 | Tweeter | 1 |
| 2013 | 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 on the BMW Alpina B7L accommodates 2 distinct speaker sizes across all listed model years: 1 inch and 4 inch.
- Door panel installations are surface-mounted or flush-mounted into cavities within the door's interior trim, meaning speaker depth and diameter must conform to the spatial constraints of the door's inner cavity and trim thickness.
- The rear door panel position places speakers at a lower height relative to seated passengers, which affects the perceived stereo imaging and the directional arrival of sound waves at ear level.
- A 1-inch tweeter in the rear door panel handles high-frequency reproduction, typically operating in ranges above 2,000 Hz, where short wavelengths require small diaphragm surface areas to reproduce accurately.
- The compact diameter of a 1-inch tweeter allows placement in tighter door panel sections, such as upper trim corners or dedicated tweeter pods, where spatial constraints limit the available mounting area.
- Tweeters are highly directional at high frequencies, so the placement of a 1-inch tweeter within the rear door panel influences the angle and dispersion of high-frequency content toward rear-seat passengers.
- The BMW Alpina B7L rear door panel supports a 4-inch midrange driver, a size associated with reproducing the mid-frequency band, generally spanning roughly 300 Hz to 5,000 Hz, which covers vocal fundamentals and many instrument harmonics.
- A 4-inch midrange driver has a relatively modest cone area, which contributes to controlled directivity in the mid-frequency range and allows tighter integration within door panel cavities that cannot accommodate larger drivers.
- Midrange drivers are designed to handle the frequency band that carries much of the intelligibility of music and speech, and a 4-inch unit in a rear door panel serves rear-cabin occupants within that acoustic role.
- The pairing of a 1-inch tweeter and a 4-inch midrange within the same rear door panel location indicates a multi-way speaker configuration at the rear door, where each driver handles a separate portion of the audible frequency spectrum.