1998 BMW 328i Speaker Sizes

The 1998 BMW 328i factory audio system contains specific factory locations for audio components. The front door panel and rear deck lid accommodate 4 inch speakers, while the front kick panel accepts a 5.25 inch speaker size. Compatible types for replacement and upgrade applications include midrange, midbass, and full-range units.

Specific details regarding locations, speaker sizes, and types are outlined in the compatibility chart.

Speaker Details by Location
Location Size Type Notes
Front Door Panel 6x8 Full-Range
  • Standard installation
  • High replacement priority
  • Replacement difficulty: low
Front Kick Panel 5.25 Midbass
  • Cramped working position
  • Medium replacement priority
  • Replacement difficulty: medium
Rear Deck Lid 4 Midrange
  • Access through trunk
  • Medium replacement priority
  • Replacement difficulty: low

1998 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: 0

Replacement priority:

High: 1 Medium: 2 Low: 0

1998 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 1998 BMW 328i features three distinct speaker locations with varying sizes, suggesting a multi-component audio architecture where different frequency ranges are distributed across separate drivers throughout the cabin.
  • Front door panels accommodate 6x8 inch full-range speakers, which typically handle the broadest frequency spectrum from bass through treble, potentially serving as the primary sound source for front passengers.
  • The 5.25 inch midbass drivers in the front kick panels likely focus on mid-to-low frequency reproduction, complementing the door speakers by reinforcing vocal clarity and lower-midrange response.
  • Rear deck lid speakers are limited to 4 inch midrange units, which generally emphasize the critical midrange frequencies where much of the musical content and vocal information resides, rather than providing full-spectrum coverage.
  • Replacing the door speakers might be considered a priority for those seeking sound improvement, given their full-range designation and larger size compared to other locations in the 1998 BMW 328i.
  • The kick panel location for midbass drivers may offer acoustic advantages, as this positioning can reduce resonance issues sometimes associated with door-mounted installations.
  • The relatively small 4 inch rear speakers suggest they contribute ambient fill rather than primary sound staging, which could influence replacement decisions based on listening priorities.
  • The combination of dedicated midbass, midrange, and full-range speakers indicates a factory design that attempted to separate frequency duties across multiple drivers rather than relying solely on coaxial or single full-range units.
  • Aftermarket speaker selection would need to account for the specific roles each location plays, as installing full-range speakers in positions designed for limited-range drivers might not yield expected results.
  • The radio chassis accepts both single DIN and double DIN head units, providing flexibility for source unit upgrades that might better drive replacement speakers.