Rockford Fosgate T1D415 15" Dual 4-Ohm Subwoofer

The Rockford Fosgate T1D415 is a 15-inch dual voice coil car subwoofer designed for systems that need substantial low-frequency output without moving to multiple drivers. Its dual 4-ohm voice coils and selectable impedance terminal support flexible amplifier matching. It is intended for a properly designed sealed or ported enclosure and a dedicated subwoofer amplifier.

With 1,000 watts RMS power handling, the T1D415 is suited to listeners building a high-power bass system with controlled, deep output. Its 15-inch format provides significant cone area for reproducing demanding bass passages. A 3-inch high-temperature aluminum voice coil and cooling-focused motor design support sustained use at appropriate power levels.

The woofer uses Rockford Fosgate's VAST surround design, which increases effective radiating cone area while retaining the external dimensions needed for installation. Its Kevlar fiber-reinforced semi-pressed paper cone is paired with a Santoprene surround for a durable moving assembly. The 16.4 mm Xmax specification gives the driver room for substantial linear cone travel.

Rockford Fosgate equips the T1D415 with an IDHS inductive damping heat sink, a double-stack ferrite motor, vented pole and spider cooling, and a rigid die-cast aluminum frame. These elements are designed to manage heat and maintain mechanical stability during demanding bass playback. The SWIFT terminal uses a reversible jumper to configure the dual coils for the intended amplifier load.

The T1D415 works well as the foundation of a trunk, hatch, or SUV bass upgrade when enclosure space and amplifier capacity are available. Rockford Fosgate specifies a 2.25-cubic-foot sealed enclosure or a 2.66-cubic-foot vented enclosure for this model. Pair it with an amplifier selected for its final 2- or 8-ohm configuration and use appropriate crossover and subsonic-filter settings for the enclosure type.

Key Features

• 15-Inch Power Subwoofer: Provides large cone area for serious low-frequency reproduction.
• 1,000-Watt RMS Handling: Supports high-output systems when matched with a suitable amplifier.
• Dual 4-Ohm Voice Coils: Enables 2- or 8-ohm nominal wiring configurations.
• VAST Surround: Increases effective radiating cone area by up to 25%.
• IDHS Heat Sink: Helps manage heat at the motor and voice coil.
• SWIFT Terminal: Uses a reversible jumper for series or parallel coil configuration.

Design & Installation

The T1D415 combines a Kevlar fiber-reinforced semi-pressed paper cone, Santoprene surround, hard-anodized aluminum dust cap, poly-cotton spiders, and a die-cast aluminum frame. Its double-stack ferrite magnet structure, extended vented pole, bumped backplate, and spider cooling vents are engineered for high-power subwoofer operation. A removable, reversible trim ring provides a finished mounting appearance, and a protective grille is included.

Allow for a 13-15/16-inch mounting cutout and 8-25/64-inch mounting depth before selecting an enclosure location. Use a rigid, well-braced enclosure; Rockford Fosgate recommends 3/4-inch MDF construction and specifies a 2.25-cubic-foot sealed box or 2.66-cubic-foot vented box. The SWIFT jumper should be securely configured for the amplifier's supported load, and Rockford Fosgate advises authorized-dealer setup for jumper changes.