BMW 750i Rear Deck Lid Speaker Size
The BMW 750i rear deck lid accommodates 4 inch speakers and supports a 1 inch speaker size as well as 0.75 inch units. Compatible audio types for these locations include tweeters and midrange units. The specifications cover a range of years from 2006 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 |
| 2012 | Tweeter | 1 |
| 2012 | Midrange | 4 |
| 2011 | Tweeter | 1 |
| 2011 | Midrange | 4 |
| 2010 | Tweeter | 1 |
| 2010 | Midrange | 4 |
| 2009 | Tweeter | 1 |
| 2009 | Midrange | 4 |
| 2008 | Tweeter | 0.75 |
| 2008 | Midrange | 4 |
| 2007 | Tweeter | 0.75 |
| 2007 | Midrange | 4 |
| 2006 | Tweeter | 0.75 |
| 2006 | 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 is a horizontal surface positioned at the base of the rear window, behind the rear passenger seats and above the trunk cavity, placing speakers in a location that projects sound upward and forward into the cabin.
- Mounting positions on the rear deck lid are subject to shallow depth clearance due to the proximity of the trunk structure beneath, which is a factor in driver selection for both the 1-inch and 4-inch openings specified.
- The 4-inch midrange driver accommodates the mid-frequency band, generally spanning roughly 300 Hz to 5 kHz, where a significant portion of vocal and instrumental content resides, making rear deck placement relevant for filling the cabin with mid-frequency energy directed toward the rear seat occupants.
- A 4-inch cone surface area is moderate, limiting low-frequency extension but allowing sufficient pistonic movement for midrange reproduction without requiring the enclosure depth that larger woofers demand - a practical fit for deck lid mounting constraints.
- Tweeters handle high-frequency content, typically above 2 kHz to 5 kHz and extending to 20 kHz or beyond, where the small diaphragm size ensures controlled, directional dispersion of treble frequencies.
- The BMW 750i rear deck lid specifications list a 1-inch tweeter for model years 2009 through 2018, a size whose diaphragm area supports wide high-frequency dispersion relative to the 0.75-inch variant, contributing to broader treble coverage from the rear of the cabin.
- For model years 2006 through 2008, the tweeter diameter is 0.75 inch, a smaller diaphragm that is common in factory installations where mounting cutout dimensions are more restricted and ultra-high-frequency extension is prioritized over output level.
- The transition in tweeter size from 0.75 inch to 1 inch between the 2008 and 2009 model years indicates a difference in the physical cutout dimensions at the rear deck lid mounting location across those production periods.
- High-frequency drivers placed on the rear deck lid benefit from the reflective surface of the rear window glass above, which can redirect treble energy toward the front of the cabin, extending the perceived soundstage reach of rear-mounted tweeters.
- Midrange drivers at the rear deck lid position radiate sound toward the headliner and rear window, distributing mid-frequency energy through the cabin via both direct and reflected paths to all seating positions.
- The pairing of a tweeter and a midrange driver at the same location - rather than a full-range driver - indicates a split-frequency approach at the rear deck, where crossover filtering separates the frequency responsibilities between the 2 driver sizes.
- Because the rear deck lid sits at ear level or slightly below for rear passengers, the 4-inch midrange driver at that position delivers midrange content with minimal path obstruction to rear seat occupants.