Mitsubishi Sigma Rear Deck Lid Speaker Size
The Mitsubishi Sigma rear deck lid accommodates a 6.5 inch speaker size and supports 9 inch units. Compatible audio types across the applicable years include full-range and midbass replacement system configurations. These specifications cover the 1989 to 1990 model years.
| Year | Type | Size (inch) |
|---|---|---|
| 1990 | Full-Range | 6x9 |
| 1989 | Midbass / Full-Range | 6.5 |
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 is a horizontal surface positioned at the base of the rear window, typically allowing speakers to fire upward into the cabin toward the headliner and front occupants.
- A 6x9 inch speaker occupies a larger surface area than a round driver, requiring an oval cutout in the deck lid panel that accommodates a longer axis of 9 inches.
- The 6x9 inch format produces a larger cone area than most round equivalents, which increases low-frequency displacement capability from a location that is already physically distant from front occupants.
- Full-range drivers reproduce the full audible spectrum from a single cone, covering low, mid, and high frequencies without requiring a crossover network or additional components at the same location.
- In the 1990 Mitsubishi Sigma rear deck lid, the 6x9 inch full-range driver handles all frequency reproduction from that position, meaning no separate tweeter or woofer is specified alongside it.
- A 6.5 inch round speaker requires a circular cutout and fits within a more compact mounting footprint than the 6x9 inch format, which affects the structural modification required on the deck lid panel.
- The 6.5 inch diameter places the driver in a size range commonly associated with mid-frequency clarity while retaining adequate cone area for modest bass reproduction.
- Midbass drivers are optimized for the frequency band roughly between 80 Hz and 500 Hz, emphasizing punch and warmth rather than extended high-frequency detail or deep low-frequency extension.
- A rear deck lid position can introduce acoustic reflections from the rear window glass above, which interacts differently depending on whether the driver is a full-range type reproducing high frequencies or a midbass driver operating in a lower band.
- The 1989 Mitsubishi Sigma rear deck lid accommodates either a midbass or full-range driver in the 6.5 inch size, indicating 2 distinct functional configurations are compatible with the same physical mounting location.
- When a 6.5 inch driver is used in midbass configuration at the rear deck lid, high-frequency reproduction from that location is absent, concentrating upper-range sound reproduction elsewhere in the vehicle's audio system.