The Porsche 944 rear door panel accommodates a 4x6 inch speaker size in that location. Full-range units are the compatible types for the audio system. These specifications cover the years 1983 to 1991.
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 door panel of the Porsche 944 accommodates a 4x6 inch speaker mounting cutout across all model years listed in the specifications, from 1983 through 1991.
A 4x6 inch oval speaker format is defined by an asymmetrical cone surface that is wider than a standard 4 inch round driver, giving the driver a larger radiating area within a constrained vertical mounting depth - a common characteristic of door panel cavities in smaller sports cars.
Door panel speaker locations are typically recessed behind a grille within a shallow, enclosed cavity formed by the door card and the door shell, which limits available depth for speaker basket and magnet assemblies.
The oval geometry of a 4x6 inch driver allows fitment in mounting locations where a round driver of equivalent radiating area would not clear due to height restrictions, making the format well suited to the dimensional constraints of the Porsche 944 rear door panel.
Full-range is the sole compatible speaker type across all 9 model years in the specifications, indicating the rear door panel mounting location is designated for single-driver, wide-spectrum reproduction rather than a dedicated low- or high-frequency driver.
A full-range driver is designed to reproduce low, midrange, and high frequencies from a single cone and voice coil assembly, typically covering a bandwidth from approximately 80 Hz to 20 kHz, though the exact response varies by individual driver design.
In a rear door panel location, a full-range driver operates within a partially enclosed acoustic space formed by the door cavity, which can act as a passive enclosure and influence the low-frequency output of the driver.
The 4x6 inch Porsche 944 rear door panel position places the driver at a lateral and relatively low mounting angle relative to the primary listening position, which affects the direct sound path and the high-frequency dispersion characteristics perceived by seated occupants.
High-frequency dispersion in oval drivers is more directional along the short axis than the long axis, meaning the orientation of the 4x6 inch driver within the Porsche 944 rear door panel affects the treble response directed toward the cabin interior.
Because full-range drivers in door panel positions handle the complete audible frequency spectrum without a crossover network, the Porsche 944 rear door panel + full-range driver combination requires no passive or active crossover integration for basic operation.