1978 BMW 733i Speaker Sizes
The 1978 BMW 733i factory audio system features a front kick panel location that accommodates a 4x6 inch speaker size, while the rear deck lid accommodates 5.25 inch units. The compatible speaker types for system replacement and upgrade consist of full-range and midbass drivers.
Specific details regarding locations, speaker sizes, and types are outlined in the compatibility chart.
| Location | Size | Type | Notes |
|---|---|---|---|
| Front Kick Panel | 4x6 | Full-Range |
|
| Rear Deck Lid | 5.25 | Midbass / Full-Range |
|
1978 BMW 733i Speaker Replacement Summary
2
total positions
1
easy to replace
0
high priority
0
professional only
Replacement difficulty:
Low: 1 Medium: 1 High: 0Replacement priority:
High: 0 Medium: 2 Low: 01978 BMW 733i Radio Slot Size (DIN)
| DIN Type | Size (inch) | Size (mm) | Notes |
|---|---|---|---|
| Single DIN | 7"×2" | 180×50 | Standard size for basic car radios with small display or no display |
- Always measure the slot before purchasing a new radio
- Check slot depth - it may vary
Additional Notes
- The front kick panel speakers in the 1978 BMW 733i typically warrant replacement consideration first, as these 4x6 inch full-range units handle most of the audible frequency spectrum from a position that directly projects sound toward occupants.
- Full-range speakers at the front kick panel locations reproduce both mid and higher frequencies without requiring separate tweeters or crossover networks, which tends to simplify installation while maintaining audio clarity.
- The rear deck lid accommodates 5.25 inch speakers that can function as either midbass drivers or full-range units, allowing for flexibility in system configuration based on whether front speakers already handle higher frequencies adequately.
- Midbass speakers in the rear deck position would focus on reproducing lower midrange and upper bass frequencies, potentially filling out the sound stage when paired with full-range front speakers.
- Upgrading to contemporary speaker technology in both locations may enhance clarity and frequency response compared to original equipment, particularly in the upper frequency ranges where older designs often showed limitations.
- The single DIN radio opening suggests head unit replacement could complement speaker upgrades by providing improved amplification and signal processing capabilities.
- The 4x6 inch front speaker size represents a non-circular configuration that was common in this era, which may require adapters or custom mounting solutions when installing modern speakers designed primarily in round formats.
- Rear deck speakers positioned at 5.25 inches offer reasonable cone area for mid-bass reproduction while fitting within the space constraints of the deck lid structure.