BMW 135i Rear Deck Lid Speaker Size
The BMW 135i rear deck lid accommodates a 1 inch speaker size and 4 inch speakers. Compatible types for these locations include tweeter and midrange units. These specifications cover the 2008 to 2013 model years.
| Year | Type | Size (inch) |
|---|---|---|
| 2013 | Tweeter | 1 |
| 2013 | Midrange | 4 |
| 2012 | Tweeter | 1 |
| 2012 | Midrange | 4 |
| 2011 | Tweeter | 1 |
| 2011 | Midrange | 4 |
| 2010 | Midrange | 4 |
| 2009 | Midrange | 4 |
| 2008 | 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 deck lid of the BMW 135i accommodates 2 distinct speaker sizes across the listed model years: 1 inch and 4 inch.
- The 4-inch midrange drivers present in all listed model years (2008 through 2013) occupy a location that is structurally integrated into the rear deck lid, a flat, horizontal surface positioned at the base of the rear window above the trunk cavity.
- A rear deck lid mounting position places speakers in a rearward-facing horizontal plane, which affects the projection angle of sound relative to the cabin's listening positions.
- 4-inch drivers in a midrange role reproduce frequencies roughly spanning 300 Hz to 5,000 Hz, covering the core band of vocal and instrumental content in an audio signal.
- At 4 inches, a driver's cone area is sufficient for midrange reproduction but limited in the low-frequency extension needed for bass content, making the rear deck lid a functional location for mid-band support rather than low-frequency reinforcement.
- The 1-inch tweeter size is listed for 2011, 2012, and 2013 model years of the BMW 135i rear deck lid, indicating a dual-driver configuration at that location during those years.
- A 1-inch tweeter is designed to handle high-frequency content, typically from approximately 2,000 Hz to 20,000 Hz, where cone mass must remain minimal to reproduce rapid transients accurately.
- The presence of a 1-inch tweeter alongside a 4-inch midrange on the rear deck lid indicates a 2-way speaker arrangement at that location in 2011, 2012, and 2013 model years.
- Tweeters are highly directional at high frequencies, and a rear deck lid mounting position angles high-frequency dispersion toward the front cabin area when the tweeter faces upward through the deck surface.
- The physical footprint of a 1-inch tweeter requires a smaller cutout diameter than the 4-inch midrange, and both must coexist within the spatial constraints of the rear deck lid panel.
- The 4-inch midrange driver size corresponds to a moderate mounting depth requirement, which is relevant in a rear deck lid where the available cavity depth above the trunk is finite and subject to structural constraints.