BMW 640i xDrive Rear Deck Lid Speaker Size
The BMW 640i xDrive rear deck lid accommodates a 1 inch speaker size and 4 inch speakers across all listed model years. Compatible types for these locations include tweeters and midrange audio units. The specifications cover a range of years from 2014 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 |
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 is a structural panel positioned at the rearmost section of the cabin, placing speakers at a distance from the primary listening position and at a relatively low vertical angle relative to seated occupants.
- Mounting locations within a rear deck lid are typically surface-flush or recessed into the panel, meaning available depth clearance is constrained by the thickness of the lid structure and any underlying mechanical or sealing components.
- The deck lid location positions speakers behind and below the rear window, which can cause the glass surface to act as a reflective boundary, influencing how sound disperses toward the front of the cabin.
- A 1 inch tweeter reproduces high-frequency content, generally from around 2,000 Hz up to 20,000 Hz or beyond, where wavelengths are short and directionality is pronounced, making the angular relationship between the tweeter and the listener particularly relevant in a rear deck placement.
- The small physical diameter of a 1 inch tweeter requires a correspondingly shallow and compact mounting cutout, which suits the limited depth typically available in a deck lid panel.
- A 4 inch midrange driver handles the vocal and upper-instrumental frequency band, roughly from 500 Hz to 5,000 Hz, where the human ear is most sensitive, and the rear deck lid placement means midrange output travels forward through the cabin toward front-seated occupants.
- At 4 inches, a midrange driver has a relatively modest cone area, which limits low-frequency extension but supports focused reproduction of the mid-band without requiring the deep enclosure volume that a woofer of larger diameter would demand.
- The pairing of a 1 inch tweeter with a 4 inch midrange in the BMW 640i xDrive rear deck lid indicates a two-way speaker arrangement at that location, with each driver covering a distinct portion of the audible frequency spectrum.
- Because both the 1 inch and 4 inch positions are present across all model years listed in the specifications, the mounting cutout dimensions and depth requirements remain consistent across the 2014 through 2018 production range of the BMW 640i xDrive.
- A midrange driver placed in the rear deck lid reproduces frequencies whose wavelengths range from several centimeters to over half a meter, meaning cabin reflections and standing waves within the vehicle interior can interact with the output from that position.