BMW 128i Rear Deck Lid Speaker Size
The BMW 128i 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 128i is a surface-mounted location positioned at the rear of the cabin, typically a flat or slightly angled panel between the rear seats and the back window.
- A 4-inch driver in a rear deck lid position radiates sound upward and forward into the cabin, with the rear glass often acting as a reflective surface that assists with sound dispersion toward front occupants.
- The 4-inch midrange speakers specified for the BMW 128i rear deck lid handle the middle portion of the audible frequency spectrum, generally covering roughly 500 Hz to 5,000 Hz, where vocals and most musical instruments are primarily reproduced.
- Midrange drivers are designed specifically to reproduce the frequency band most sensitive to human hearing, where clarity and tonal accuracy are most perceptible.
- A 4-inch cone diameter limits low-frequency extension due to reduced surface area and typically reduced excursion, making the rear deck placement reliant on separate bass reproduction elsewhere in the system.
- The 1-inch tweeter specified for the 2011, 2012, and 2013 model years occupies a compact footprint, consistent with the spatial constraints of a rear deck lid location where available mounting depth and surface area are limited.
- Tweeters reproduce high frequencies, generally from approximately 2,000 Hz to 20,000 Hz, and a 1-inch dome or cone tweeter is a common form factor suited to the upper end of that range.
- The rear deck lid location places tweeters at a distance from the front listening position, which can affect the perceived stereo imaging of high-frequency content due to the directional nature of high-frequency sound waves.
- 1-inch tweeters are highly directional at the upper limits of their frequency range, meaning their placement angle on the rear deck lid influences how the high-frequency energy is aimed within the cabin.
- The pairing of a 1-inch tweeter and a 4-inch midrange at the same rear deck lid location, as specified for the BMW 128i in 2011 through 2013, indicates a 2-way speaker configuration at that installation point.
- The deck lid surface is typically constructed from sheet metal with a relatively shallow cavity beneath, which constrains the maximum mounting depth available for either the 4-inch midrange or the 1-inch tweeter.