BMW 640i Gran Coupe Rear Side Panel Speaker Size
The BMW 640i Gran Coupe rear side panel location accommodates a 4 inch speaker size. Midrange units are the compatible audio type for the rear side panel. These specifications cover the 2018 model year.
| Year | Type | Size (inch) |
|---|---|---|
| 2018 | Midrange | 4 |
Speaker Types
| Type | Description |
|---|---|
| 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 side panel location in the BMW 640i Gran Coupe accommodates a 4-inch driver, a compact diameter suited to enclosed or semi-enclosed cavities within trimmed interior panels rather than open-baffle door installations.
- Panel-mounted speaker positions in vehicles of the 640i Gran Coupe's body class typically sit within rigid structural enclosures formed by the bodywork itself, which affects the resonant behavior and rear-wave management of any driver installed there.
- A 4-inch driver in a rear side panel position operates across a mid-frequency range, generally covering approximately 300 Hz to 5 kHz, contributing the vocal and upper-instrumental frequencies that define presence and clarity in a cabin audio stage.
- The compact cone area of a 4-inch driver limits low-frequency output and excursion capability, making the rear side panel position acoustically dependent on a separate woofer or subwoofer to reproduce bass content below its effective range.
- The midrange type specified for the BMW 640i Gran Coupe rear side panel is a dedicated bandpass driver, designed to reproduce the frequency range where human speech and most musical harmonics are concentrated, without the crossover responsibilities of a full-range or coaxial driver.
- A midrange driver of 4 inches in a side panel location projects sound laterally across the rear cabin, contributing to the spatial width of the soundfield perceived by rear-seat occupants.
- The midrange designation indicates a driver without an integrated tweeter, meaning the upper frequency extension of the rear side panel position relies on crossover integration with a separate high-frequency driver elsewhere in the vehicle's speaker system.
- The side panel mounting geometry places the driver at a fixed angle determined by the panel's contour, which influences the dispersion axis and the degree to which direct sound reaches rear passengers versus reflecting off interior surfaces.