BMW 640i xDrive Speaker Size
Speaker size, type, and location chart for BMW 640i xDrive models from 2014 to 2018 production years.
As an Amazon Associate, we may earn a commission from purchases made through links marked. Read more in our disclaimer.
Rear Side Panel Speaker
| Years | Type | Size (inch) |
|---|---|---|
| 2014 - 2018 | Tweeter | 1 |
| 2014 - 2018 | Midrange | 4 |
Center Dash Speaker
| Years | Type | Size (inch) |
|---|---|---|
| 2014 - 2018 | Tweeter | 1 |
| 2014 - 2018 | Midrange | 4 |
Front Door Panel Speaker
| Years | Type | Size (inch) |
|---|---|---|
| 2014 - 2018 | Tweeter | 1 |
| 2014 - 2018 | Midrange | 4 |
Rear Deck Lid Speaker
| Years | Type | Size (inch) |
|---|---|---|
| 2014 - 2018 | Tweeter | 1 |
| 2014 - 2018 | Midrange | 4 |
Below Seats Speaker
| Years | Type | Size (inch) |
|---|---|---|
| 2014 - 2018 | Subwoofer | 8 |
BMW 640i xDrive Speaker FAQ
Which speakers should I replace first in my BMW 640i xDrive for the biggest sound improvement?
Start with the front door panel 4 inch coaxial component speakers. These handle most of your music's midrange and vocal frequencies - around 200Hz to 4kHz typically. The front stage creates your primary listening experience in the BMW 640i xDrive. After that, consider the 8 inch subwoofer below the seats since it manages the critical 40-120Hz bass range. The tweeters can wait unless you're hearing obvious distortion above 3kHz.
What's the difference between the coaxial component speakers in the front doors versus the coaxial full-range speakers elsewhere?
Component speakers separate the tweeter and woofer elements, allowing better frequency response control. The front door setup in your BMW 640i xDrive uses dedicated 1 inch tweeters paired with 4 inch mid drivers. Full-range coaxials in the rear locations combine everything into one unit - convenient but potentially less precise. Components typically handle 50-60 watts RMS better than full-range designs. The crossover network might be external or built into the BMW 640i xDrive's amplifier system.
Why does my BMW 640i xDrive have so many 1 inch tweeters in different locations?
Multiple tweeter placement creates controlled high-frequency dispersion throughout the cabin. Center dash tweeters fill the soundstage gap between left and right channels - usually handling 2.5kHz and up. Rear tweeters provide ambient fill and can enhance surround effects if your BMW 640i xDrive has logic-7 or similar processing. Door panel tweeters focus on the primary stereo image. Too many active tweeters can create phase issues though, so some might be filtered differently or run at lower levels.
Can I upgrade just the 8 inch subwoofer below the seats without touching other speakers?
Probably, but check the impedance first - likely 4 ohms in the BMW 640i xDrive setup. The under-seat location limits power handling to maybe 100-150 watts RMS due to space constraints. A quality 8 inch sub there should extend down to 35Hz reasonably well. You'll want something with decent excursion capability since the enclosure volume is probably limited. The existing amplifier channel might need adjustment if you change sensitivity ratings significantly.
What power requirements should I consider for the 4 inch speakers in my BMW 640i xDrive?
Most 4 inch aftermarket speakers handle 40-80 watts RMS comfortably. The BMW 640i xDrive's factory amplifier probably outputs 25-50 watts per channel to these locations. Look for speakers with 88-92dB sensitivity ratings for good efficiency. The rear deck and side panel full-range speakers might see slightly less power than the front components. Impedance should stay at 4 ohms to match the amplifier's designed load. Higher power handling doesn't always mean better sound quality in these smaller drivers.