Rockford Fosgate R2SD4-12 12" Dual 4-Ohm Shallow Subwoofer

The Rockford Fosgate Prime R2SD4-12 is a 12-inch shallow-mount subwoofer designed for vehicle audio systems with limited enclosure depth. Its dual 4-ohm voice coils provide wiring flexibility while its 250-watt RMS rating supports a properly matched external amplifier. It is a practical option for compact trunks, behind-seat truck installations, and other space-conscious bass upgrades.

This subwoofer is engineered to add low-frequency support without requiring the depth of a conventional full-size 12-inch driver. Its published frequency response is 43 to 250 Hz, making it intended for bass reproduction rather than full-range speaker duty. A sealed enclosure is the primary recommended application for controlled, space-efficient bass performance.

The R2SD4-12 uses a mica-injected polypropylene cone and high-density poly-foam surround to support repeated cone movement. A high-temperature copper voice coil on an aluminum former is paired with stitched flexible lead wires and a poly-cotton spider. These components are intended to support stable operation at its rated power level.

Its shallow motor assembly is supported by a heavy-gauge stamped-steel StampCast basket with integrated spider venting. The venting design helps move heat away from the motor structure during operation. An integrated semi-flexible PVC trim ring gives the installed woofer a finished appearance.

With dual 4-ohm coils, a single R2SD4-12 may be wired for a 2-ohm or 8-ohm final load, depending on amplifier capability and wiring method. It needs a compatible subwoofer amplifier, enclosure, wiring, and installation hardware to operate as part of a complete system. Its 3.602-inch mounting depth and 11.25-inch cutout requirement should be checked before building or selecting an enclosure.

Key Features

• Shallow-Mount 12-Inch Design: Uses a 3.602-inch mounting depth for installations with limited space.
• Dual 4-Ohm Voice Coils: Allows 2-ohm or 8-ohm single-subwoofer wiring configurations.
• 250 Watts RMS Handling: Supports amplifier matching up to its continuous rated power.
• Mica-Injected Polypropylene Cone: Provides a rigid cone material for bass reproduction.
• Spider-Vented StampCast Basket: Helps manage motor heat through integrated basket venting.
• Sealed-Enclosure Optimization: Supports compact sealed-box installations with recommended enclosure data.

Design & Installation

The R2SD4-12 combines a mica-injected polypropylene cone, poly-foam surround, polypropylene dustcap, single poly-cotton spider, and aluminum voice-coil former. Its heavy-gauge stamped-steel frame incorporates integrated spider venting, while the all-metal dual compression terminals accept 12 AWG speaker wire. The subwoofer also includes an integrated PVC trim ring.

Plan for an 11.25-inch cutout diameter and 3.602 inches of mounting depth, plus clearance behind the motor and around the terminals. Rockford Fosgate specifies a 0.90-cubic-foot sealed enclosure as a recommended alignment; a 1.79-cubic-foot ported enclosure tuned to 40 Hz is also published. Use a compatible external amplifier and configure the two 4-ohm voice coils only for an impedance load the amplifier is rated to drive.