BMW 640i xDrive Gran Coupe Rear Door Panel Speaker Size
The BMW 640i xDrive Gran Coupe rear door panel accommodates a 1 inch speaker size and supports 4 inch speakers. Compatible speaker types for the location include tweeters and midrange units. The specifications cover the 2014 to 2018 model range.
| 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 door panel of the BMW 640i xDrive Gran Coupe accommodates 2 distinct speaker sizes across all listed model years: 1 inch and 4 inch.
- A 1-inch tweeter in a rear door panel occupies a shallow, compact mounting cavity, typically requiring minimal baffle depth, which suits the constrained spatial geometry of a door panel's upper or mid-section.
- Tweeters in the 1-inch class reproduce high frequencies, generally from around 2 kHz upward, and at the rear door location, contribute to the high-frequency component of the rear soundstage within the cabin.
- The 4-inch midrange driver fits within a moderately sized mounting cutout in the rear door panel, a location where door cavity resonance and panel vibration can influence midrange reproduction.
- Midrange drivers in the 4-inch class handle the vocal and instrumental frequency band, typically spanning roughly 300 Hz to 5 kHz, which in a rear door position means mid frequencies are projected toward the passenger seating area from a low lateral angle.
- The pairing of a 1-inch tweeter and a 4-inch midrange within the same rear door panel reflects a 2-way speaker arrangement at the rear, with each driver assigned a distinct frequency band rather than a single driver covering the full range.
- A 4-inch midrange driver, compared to larger woofer-sized drivers, has limited low-frequency extension, meaning bass reproduction is not a function of the rear door panel location in this vehicle.
- The 1-inch tweeter's small diaphragm area allows for wide dispersion of high frequencies, which at the rear door panel location means high-frequency energy can radiate broadly across the rear seating area.
- The BMW 640i xDrive Gran Coupe rear door panel retains the same 1-inch and 4-inch speaker configuration across the 2014 through 2018 model years, indicating dimensional consistency in the rear door panel mounting locations across the full listed production span.
- Rear door panel mounting locations generally position drivers within a few inches of seated occupant ear height or below, affecting the perceived directional character of midrange frequencies in the cabin.