The Dodge St. Regis rear location accommodates a 6x9 inch speaker size, consistent across all available model years. Compatible types for the rear audio system include full-range units. These specifications cover a range of years from 1979 to 1981.
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 speaker location in the Dodge St. Regis accommodates a 6x9 inch mounting footprint across the 1979, 1980, and 1981 model years.
A 6x9 inch speaker requires an elongated oval cutout, meaning the rear mounting surface in the Dodge St. Regis is designed to accept an asymmetrical frame rather than a circular one.
The 6x9 inch format produces a larger cone surface area than a standard round speaker of comparable diameter, which increases low-frequency displacement from the rear position.
Mounting a 6x9 inch driver in a rear location places the speaker behind or beneath the rear occupants, a position that tends to reinforce bass and lower midrange frequencies due to proximity to enclosed cabin surfaces.
The rear mounting cavity of the Dodge St. Regis is sized consistently at 6x9 inches across all 3 listed model years, indicating no dimensional change to the rear speaker location during that production period.
Full-range is the sole compatible speaker type for the rear location in the Dodge St. Regis, meaning a single driver is intended to reproduce the entire audible frequency spectrum from that position.
A full-range driver combines low, mid, and high frequency reproduction within one unit, relying on a main cone for bass and midrange alongside a small integrated whizzer cone or tweeter element for upper frequencies.
Because a full-range driver handles the complete frequency spectrum, the rear location in the Dodge St. Regis does not rely on a separate crossover network or supplemental tweeter to reproduce high-frequency content.
The 6x9 inch cone area of a full-range driver in the rear of the Dodge St. Regis allows adequate low-frequency output without a dedicated woofer, given that the larger surface area moves more air than smaller full-range formats.