BMW 735i Rear Deck Lid Speaker Size
The BMW 735i rear deck lid accommodates a 5.25 inch speaker size across all listed model years. Compatible speaker types for the location include midbass and full-range audio system units. The specifications cover a range of years from 1985 to 1989.
| Year | Type | Size (inch) |
|---|---|---|
| 1989 | Midbass / Full-Range | 5.25 |
| 1988 | Midbass / Full-Range | 5.25 |
| 1987 | Midbass / Full-Range | 5.25 |
| 1986 | Midbass / Full-Range | 5.25 |
| 1985 | Midbass / Full-Range | 5.25 |
Speaker Types
| Type | Description |
|---|---|
| Midbass | A driver tuned for upper bass and lower midrange, roughly from 80 Hz to 500 Hz. It has longer cone travel than a full-range unit, which supports stronger bass in doors and panels. |
| Full-Range | A single driver that reproduces bass through treble without a separate crossover network. It is the simplest replacement option and is common in factory audio systems. |
Additional Notes
- The rear deck lid of the BMW 735i is the mounting surface positioned at the rearmost horizontal panel of the cabin, situated between the rear seat and the back window, a location that places speakers in a rearward-facing or upward-angled orientation relative to the passenger compartment.
- A 5.25 inch driver fits within the spatial constraints of the rear deck lid, where available cutout depth and surface area are typically moderate, accommodating a mid-sized cone without the structural demands a larger woofer would impose on the panel.
- The 5.25 inch diameter produces a cone area suited to the mid-frequency range, generally handling frequencies from the upper bass region through the midrange, which aligns with the acoustic demands of a rear deck position that must project sound forward toward seated occupants.
- At 5.25 inches, the driver's moving mass and cone excursion characteristics place the low-frequency extension typically in the range of approximately 80 Hz to 100 Hz and above, depending on enclosure conditions presented by the deck lid cavity beneath the mounting surface.
- The rear deck lid of the BMW 735i functions as an acoustically significant boundary, as the enclosed space beneath the panel acts as a passive enclosure volume that interacts directly with the rear cone surface of any mounted driver, influencing resonance and bass response.
- Midbass is a speaker type engineered to reproduce the frequency band roughly between 80 Hz and 500 Hz, covering the lower midrange and upper bass registers that contribute to the weight and body of vocals and lower-pitched instruments.
- A midbass driver at the rear deck lid position of the BMW 735i reinforces the low-mid frequencies in a zone of the cabin where bass energy from front-mounted sources may diminish, supporting a more even low-frequency distribution across the listening area.
- Full-range is a speaker type designed to reproduce a broad span of the audible spectrum from bass through treble within a single driver, achieved through cone and surround materials selected to maintain controlled high-frequency dispersion alongside low-frequency output.
- A full-range driver mounted at the rear deck lid handles treble reproduction from a rearward position, and at 5.25 inches the cone's inertia begins to limit high-frequency dispersion, making the driver's tweeter dome or whizzer cone the primary source of upper-frequency output at that location.
- The rear deck lid mounting position places the speaker closer to the rear occupants than to the front, meaning a full-range driver at the BMW 735i rear deck lid location projects both mid and high frequencies at a short distance to rear-seat listeners while relying on reflective surfaces to distribute sound toward the front of the cabin.