2009 BMW 135i Speaker Sizes
The 2009 BMW 135i speaker size chart provides factory specifications for audio system components in front door panels, rear side panels, rear deck lid, and below seats. Information covers replacement sizes and locations for stock speakers, including details relevant to aftermarket upgrade compatibility. Data reflects OEM audio configurations for this vehicle model.
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| Location | Size | Type | Notes |
|---|---|---|---|
| Below Seats | 8 | Subwoofer |
|
| Front Door Panel | 0.75 | Tweeter |
|
| Front Door Panel | 4 | Midrange |
|
| Rear Deck Lid | 4 | Midrange |
|
| Rear Side Panel | 0.75 | Tweeter |
|
| Rear Side Panel | 4 | Midrange |
|
2009 BMW 135i Speaker Replacement Summary
6
total positions
3
easy to replace
2
high priority
0
professional only
Replacement difficulty:
Low: 3 Medium: 3 High: 0Replacement priority:
High: 2 Medium: 2 Low: 22009 BMW 135i Radio Slot Size (DIN)
| DIN Type | Size (inch) | Size (mm) | Notes |
|---|---|---|---|
| Single DIN or Double DIN | 7"×2" or 7"×4" | 180×50 or 180×100 | Vehicle supports both radio sizes |
- Always measure the slot before purchasing a new radio
- Check slot depth - it may vary
Additional Notes
- The 2009 BMW 135i uses a component speaker system with separated tweeters and midrange drivers rather than full-range coaxial speakers, which typically allows for better sound staging and frequency separation in the cabin.
- Tweeters are positioned in both front door panels and rear side panels at 0.75 inch sizes, handling higher frequency reproduction across the listening environment.
- Midrange drivers at 4 inches are distributed across three locations including front door panels, rear side panels, and rear deck lid, providing vocal and mid-frequency coverage throughout the interior.
- An 8 inch subwoofer located below the seats handles low-frequency output, suggesting a factory premium audio configuration with dedicated bass management.
- Replacing the front door panel components may take priority for audio upgrades, as these speakers generally contribute most directly to the driver and front passenger listening experience.
- The distributed midrange setup across five locations indicates that partial upgrades could leave tonal imbalances if only certain speakers are replaced while others remain stock.
- Aftermarket tweeters would need to fit the 0.75 inch mounting locations, which may limit options compared to more common 1 inch tweeter sizes found in some replacement component sets.
- The under-seat subwoofer placement at 8 inches presents space constraints that could affect aftermarket subwoofer selection, as depth and mounting configuration become critical factors.
- Both single DIN and double DIN head units are compatible, providing flexibility for stereo upgrades ranging from basic replacements to touchscreen navigation units.
- Upgrading to higher sensitivity speakers in the midrange positions could improve output levels without requiring amplifier modifications, though power handling specifications would still need consideration.