BMW 328i Rear Door Panel Speaker Size
The BMW 328i rear door panel accommodates a 1 inch speaker size, along with 0.75, 2.5, and 4 inch speakers, across the years covered. Compatible audio types for these units include tweeters and midrange components within the system. These specifications cover a range of model years from 1996 to 2015.
| Year | Type | Size (inch) |
|---|---|---|
| 2015 | Tweeter | 1 |
| 2015 | Midrange | 4 |
| 2014 | Tweeter | 1 |
| 2014 | Midrange | 4 |
| 2013 | Tweeter | 1 |
| 2013 | Midrange | 4 |
| 2011 | Tweeter | 1 |
| 2011 | Midrange | 4 |
| 2010 | Tweeter | 0.75 |
| 2010 | Tweeter | 1 |
| 2010 | Midrange | 4 |
| 2009 | Midrange | 4 |
| 2008 | Midrange | 4 |
| 2007 | Tweeter | 0.75 |
| 2007 | Midrange | 4 |
| 2000 | Midrange | 2.5 |
| 1996 | 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 328i rear door panel accommodates speakers mounted within the door's inner panel structure, a location that positions drivers toward the lower portion of the listening environment and subjects enclosures to road vibration and potential moisture exposure.
- A 4-inch midrange speaker appears across the widest range of model years in the rear door panel specifications, indicating a consistent cavity size suited to mid-frequency reproduction, roughly covering 300 Hz to 5,000 Hz, where vocals and most musical instruments are centered.
- Midrange speakers in a rear door panel location direct sound upward and inward toward the cabin, contributing to the rear soundstage and filling in the frequency band between subwoofer or woofer output and high-frequency tweeter output.
- The 1-inch tweeter handles high-frequency reproduction, typically from around 2,000 Hz to 20,000 Hz, and at the rear door panel location, a driver of that diameter maintains relatively wide dispersion, distributing treble detail across the rear seating area.
- A 0.75-inch tweeter, listed for the 2010 and 2007 model years alongside the 4-inch midrange, has a smaller diaphragm than the 1-inch variant, which affects the upper boundary of frequency extension and the directional pattern of high-frequency output within the door cavity.
- The 2010 BMW 328i rear door panel is notable in the specifications for listing both a 0.75-inch and a 1-inch tweeter as compatible types, indicating the mounting location can accommodate either driver diameter for that year.
- A 2.5-inch midrange, listed for the 2000 model year, operates in a similar frequency band as the 4-inch midrange but with a smaller radiating surface, which reduces the efficiency of moving air at lower midrange frequencies and affects the output level the driver can produce within the door panel cavity.
- Door panel mounting creates a partially enclosed rear air volume behind the speaker cone, which can influence the low-frequency roll-off point of a midrange driver and contribute coloration to the lower edge of its operating range.
- The simultaneous presence of a tweeter and a midrange at the rear door panel location, as seen across most listed years, indicates a multi-driver configuration within a single door, requiring the mounting cutouts and depth clearances to accommodate 2 separate speaker positions.
- At the rear door panel, the listening axis for door-mounted tweeters is generally off-axis relative to seated passengers, since the driver sits low on the door surface rather than at ear height, affecting the perceived treble balance and imaging from the rear speakers.