BMW 320i Rear Door Panel Speaker Size
The BMW 320i rear door panel accommodates a 1 inch speaker size, supports 4 inch speakers, and accepts 5.25 inch units. Compatible audio types across these sizes include tweeter, midrange, midbass, and full-range. The specifications in this replacement chart cover a range of years from 1977 to 2018.
| 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 |
| 2014 | Tweeter | 1 |
| 2014 | Midrange | 4 |
| 2013 | Tweeter | 1 |
| 2013 | Midrange | 4 |
| 1983 | Midbass / Full-Range | 5.25 |
| 1982 | Midbass / Full-Range | 5.25 |
| 1981 | Midbass / Full-Range | 5.25 |
| 1980 | Midbass / Full-Range | 5.25 |
| 1979 | Midbass / Full-Range | 5.25 |
| 1978 | Midbass / Full-Range | 5.25 |
| 1977 | Midbass / Full-Range | 5.25 |
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. |
| Midbass | A driver tuned for upper bass and lower midrange, roughly from 80 Hz to 500 Hz. It has longer cone travel than a full-range unit, which supports stronger bass in doors and panels. |
| Full-Range | A single driver that reproduces bass through treble without a separate crossover network. It is the simplest replacement option and is common in factory audio systems. |
Additional Notes
- The BMW 320i rear door panel location accommodates speakers mounted within the interior door panel structure, a position that places drivers in close proximity to seated passengers while directing sound laterally across the cabin.
- Rear door panel installations are subject to spatial constraints defined by the panel's internal cavity depth and baffle cutout dimensions, which determine the maximum cone excursion and basket diameter a speaker can physically occupy.
- The 1-inch tweeter specified for 2013 through 2018 model years is a high-frequency driver, typically reproducing frequencies from around 2 kHz to 20 kHz, and the small diaphragm size at the rear door panel position contributes to wide horizontal dispersion of treble content toward rear cabin occupants.
- A 1-inch tweeter's compact form factor suits tight mounting locations within a door panel, as the shallow depth and small cutout requirement make integration into constrained panel geometry practical.
- The 4-inch midrange driver specified alongside the 1-inch tweeter for the BMW 320i rear door panel in 2013 through 2018 represents a dedicated mid-frequency unit, generally covering approximately 300 Hz to 5 kHz, handling vocal clarity and instrumental presence without extending into bass or extreme treble regions.
- A 4-inch midrange cone is small enough to reproduce mid frequencies with reduced mass, which supports accurate transient response in the vocal and upper harmonic range within the rear door environment.
- The pairing of a 1-inch tweeter and a 4-inch midrange in the rear door panel indicates a multi-driver configuration at that location, requiring the panel to accommodate at least 2 separate mounting cutouts per door.
- The 5.25-inch driver specified for 1977 through 1983 model years is a larger-diameter unit relative to the 4-inch midrange, and the greater cone area allows for reproduction of lower frequencies, typically reaching down into the midbass region around 80 Hz to 100 Hz depending on enclosure conditions.
- The compatible types listed for the 5.25-inch position are midbass and full-range, where a midbass driver focuses on the lower-mid and upper-bass frequency band while a full-range driver is designed to reproduce a broader spectrum from bass through treble within a single cone.
- A 5.25-inch full-range driver in a rear door panel location can serve as the sole driver per door, covering the frequency range without a dedicated tweeter or midrange companion, which corresponds to the absence of additional type entries for those earlier model years in the specifications.
- The rear door panel's semi-sealed or partially open cavity behind the speaker cone influences low-frequency output, as a 5.25-inch midbass driver depends on available internal door volume to support bass extension before mechanical limits of the door cavity reduce output.
- Door panel speaker locations are generally subject to road noise and structural vibration coupling, which can affect perceived signal clarity, and the frequency roles of midrange and tweeter drivers placed at the rear door are particularly sensitive to resonances introduced through the panel substrate.