1999 BMW 328i Speaker Sizes
The 1999 BMW 328i factory audio system features specific mounting positions containing a 4 inch speaker size in the rear deck lid, while the front kick panel accepts 5.25 inch units, and the front door panel accommodates 6x8 inch units. Midrange, midbass, and full-range units serve as compatible speaker types for audio replacement and upgrade procedures.
Specific details regarding locations, speaker sizes, and types are outlined in the compatibility chart.
| Location | Size | Type | Notes |
|---|---|---|---|
| Front Door Panel | 6x8 | Full-Range |
|
| Front Kick Panel | 5.25 | Midbass |
|
| Rear Deck Lid | 4 | Midrange |
|
1999 BMW 328i Speaker Replacement Summary
3
total positions
2
easy to replace
1
high priority
0
professional only
Replacement difficulty:
Low: 2 Medium: 1 High: 0Replacement priority:
High: 1 Medium: 2 Low: 01999 BMW 328i 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 front door panels in the 1999 BMW 328i accept 6x8 inch full-range speakers, which could handle the complete frequency spectrum from bass through treble without requiring separate components.
- Front kick panel locations accommodate 5.25 inch midbass drivers, suggesting a factory audio design that separated lower frequency reproduction from higher frequencies in the front soundstage.
- Rear deck lid positions are limited to 4 inch midrange speakers, indicating these locations were likely intended to supplement mid-frequency output rather than provide substantial bass response.
- The oval 6x8 inch configuration in the front doors may require mounting brackets or adapters when installing aftermarket speakers designed for standard round sizes.
- Upgrading the front door full-range speakers in the 1999 BMW 328i would potentially offer the most noticeable sound improvement, given their larger size and full-spectrum capability compared to the other factory locations.
- The combination of dedicated midbass drivers in the kick panels and full-range speakers in the doors suggests the factory system was engineered with some attention to frequency distribution across the cabin.
- The 4 inch rear speakers, being midrange-specific, would not contribute significantly to low-frequency output, placing greater importance on the front speaker locations for bass reproduction.
- Both single DIN and double DIN head units are compatible with the radio opening, providing flexibility for aftermarket stereo installations without dashboard modifications.