BMW 640i xDrive Gran Coupe Rear Deck Lid Speaker Size
The BMW 640i xDrive Gran Coupe rear deck lid accommodates a 1 inch speaker size and 4 inch speakers. Compatible types for these locations include tweeter and midrange audio units. These specifications cover the 2016 to 2018 system range.
| Year | Type | Size (inch) |
|---|---|---|
| 2018 | Tweeter | 1 |
| 2018 | Midrange | 4 |
| 2017 | Tweeter | 1 |
| 2017 | Midrange | 4 |
| 2016 | Tweeter | 1 |
| 2016 | 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 640i xDrive Gran Coupe is a surface-mounted location positioned at the rearmost horizontal panel of the cabin, situated between the rear passenger area and the trunk.
- Deck lid placements are typically flush or near-flush installations, where speaker depth clearance is limited by the panel's construction and the proximity of the trunk cavity beneath.
- The 1-inch driver size listed for the rear deck lid corresponds to a tweeter, a speaker type engineered to reproduce high frequencies, generally from around 2,000 Hz up to 20,000 Hz or beyond.
- At 1 inch, the diaphragm surface area is small by design, as tweeter operation depends on minimal mass to move air rapidly enough to produce high-frequency wavelengths accurately.
- The BMW 640i xDrive Gran Coupe rear deck lid accepts a 1-inch tweeter, which in a rear deck position contributes high-frequency extension and spatial detail to the rear soundstage.
- Tweeters are inherently directional at high frequencies, meaning placement angle and baffle geometry on the deck lid influence how high-frequency content disperses toward rear and front passengers.
- The 4-inch driver size listed corresponds to a midrange speaker type, which handles the middle portion of the audible spectrum, typically from roughly 300 Hz to 5,000 Hz, covering vocals, instruments, and much of speech intelligibility.
- A 4-inch midrange in a rear deck lid location reproduces frequencies that carry significant perceived tonal presence, and the relatively shallow mounting depth typical of deck lid panels suits the compact enclosure requirements of a dedicated midrange driver.
- Unlike a woofer, a 4-inch midrange driver is not designed to move large volumes of air for bass reproduction, making the mounting depth constraints of a deck lid panel acoustically compatible with the driver's mechanical range.
- The pairing of a 1-inch tweeter and a 4-inch midrange at the rear deck lid indicates a multi-driver configuration at that location, where each driver is assigned a distinct frequency band rather than a single full-range driver handling the entire spectrum.