Rockford Fosgate R2D4-12 12" Dual 4-Ohm Subwoofer

The Rockford Fosgate R2D4-12 is a 12-inch dual voice coil car subwoofer designed to add controlled low-frequency output to a vehicle audio system. Rated for 250 watts RMS, it is suited to systems that need a dedicated bass driver without requiring extreme amplifier power. Its dual 4-ohm voice coils provide wiring flexibility when matching the subwoofer to a compatible amplifier.

This model is a practical choice for listeners building a first subwoofer system or upgrading factory speakers with fuller low-end response. It can be used in either a sealed or vented enclosure, allowing the enclosure type to be selected around available space and listening preferences. The manufacturer provides recommended box volumes for both approaches.

The R2D4-12 uses a mica-injected polypropylene cone and a high-density poly-foam surround. Its poly-cotton spider, copper voice coil, and aluminum voice coil former are engineered for repeated cone movement under normal operating conditions. A linear spider with embedded 16 AWG tinsel leads helps support reliable signal transfer to the moving assembly.

Its motor system uses an extended pole piece and bumped, vented backplate to support cooling and cone travel. The stamped steel StampCast basket incorporates spider venting, while a removable PVC motor cover and integrated PVC trim ring complete the exterior design. Dual 12 AWG compression terminals provide a secure connection point for speaker wire.

For system integration, the R2D4-12 should be paired with an amplifier and wiring configuration that safely matches its dual 4-ohm voice coils. Rockford Fosgate recommends an active low-pass crossover in the 80-100 Hz range at 12 dB per octave for subwoofer use. It is intended for custom enclosure installations and is supplied as a raw subwoofer rather than a loaded enclosure.

Key Features

• Dual 4-Ohm Voice Coils: Supports flexible series or parallel wiring options.
• 250-Watt RMS Handling: Matches moderate-power subwoofer amplifier systems.
• 12-Inch Driver: Adds dedicated low-frequency output to car audio systems.
• Mica-Injected Polypropylene Cone: Provides a durable, rigid cone structure.
• StampCast Vented Basket: Helps support motor cooling during operation.
• Sealed Or Vented Compatibility: Allows installation in either recommended enclosure type.

Design & Installation

The R2D4-12 combines an injection-molded polypropylene cone, sealed half-roll poly-foam surround, tear- and fatigue-resistant poly-cotton spider, and heavy-gauge stamped steel frame. Its high-temperature copper voice coil is wound on an aluminum former, and the motor assembly includes an extended pole and vented backplate. A semi-flexible removable PVC motor cover, integrated trim ring, and all-metal compression terminals support the overall installation-ready design.

Allow for a 5.067-inch mounting depth and an 11.25-inch cutout diameter when planning the enclosure baffle. Rockford Fosgate lists a 1.02 cubic foot sealed enclosure or a 1.79 cubic foot vented enclosure as recommended applications; the vented design uses a 4-inch diameter, 9.3-inch-long port tuned to 45 Hz. Wire the two 4-ohm voice coils only in a configuration compatible with the amplifier, and use an active 80-100 Hz low-pass crossover as recommended in the owner's manual.