1981 BMW 733i Speaker Sizes
The 1981 BMW 733i speaker size chart provides factory specifications for audio system components requiring replacement or aftermarket upgrade. Information includes speaker locations in the front kick panel and rear deck lid areas, with details on factory sizes and compatible aftermarket options for each position within the audio system.
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| Location | Size | Type | Notes |
|---|---|---|---|
| Front Kick Panel | 4x6 | Full-Range |
|
| Rear Deck Lid | 5.25 | Midbass / Full-Range |
|
1981 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: 01981 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 positions in the 1981 BMW 733i accommodate 4x6 inch full-range speakers, which typically feature oval configurations designed to fit within constrained lower dashboard spaces. These full-range units handle both midrange frequencies and treble output without requiring separate tweeters, though their compact nature may limit low-frequency extension compared to larger speaker formats.
- Rear deck lid locations accept 5.25 inch speakers with compatibility extending to both midbass and full-range types. The dual compatibility suggests some flexibility in system configuration, where midbass speakers could focus on lower midrange frequencies while leaving upper ranges to dedicated tweeters, or full-range speakers could operate independently across the frequency spectrum.
- Upgrading the kick panel speakers might present a reasonable starting point for sound enhancement, as these front-positioned drivers contribute significantly to stereo imaging and vocal clarity. The smaller 4x6 inch size may benefit from units featuring higher sensitivity ratings to maximize output from the available cone area.
- The rear deck installation potentially serves as a secondary sound source, where 5.25 inch midbass drivers could supplement the front speakers by handling frequencies roughly between 80 Hz and 500 Hz. This approach would likely create a more balanced sound stage compared to relying solely on the smaller front kick panel speakers for bass reproduction.
- Full-range speakers in the rear deck position would operate across a broader frequency range, though physical positioning behind the listening area may affect the perceived tonal balance. The 1981 BMW 733i configuration suggests an original system design that distributed audio output between front and rear locations rather than concentrating drivers in door panels.
- Speaker replacements would need to account for the single DIN radio specification, which indicates standard aftermarket head unit compatibility but may suggest limited power output compared to larger double DIN systems. Higher efficiency speakers might compensate for potentially modest amplifier power from period-correct or replacement head units.