Rockford Fosgate R500X1D Prime 500 Watt Class-D Mono Amplifier

More power. Less heat. Purpose-built for bass.

Product Overview

The Rockford Fosgate R500X1D is a mono Class-D amplifier from the Prime series, delivering 500W RMS into a 2-ohm load or 300W RMS into 4 ohms from a chassis that measures just 5.02 x 17.19 x 21.59 cm. Class-D circuit topology runs at an average efficiency of 89%, meaning less energy is lost as heat compared to Class A/B designs. The result is a compact, cool-running amplifier that punches well above its size and fits easily into tight boot or under-seat locations.

Frequency response is fixed between 20Hz and 250Hz (+/-1dB), making the R500X1D a dedicated subwoofer amplifier. It pairs naturally with a separate full-range amplifier in a two-amp system one amplifier handling mids and highs, the R500X1D handling subwoofer duty. On-board features include variable Punch Bass EQ (+12dB @ 45Hz), a variable low-pass crossover (50Hz–250Hz), RCA pass-through outputs for daisy-chaining, high-level inputs for factory deck compatibility, and a Remote Punch Level Control (PLC) for under-dash or centre console mounting. CEA-2006 compliance confirms the 500W RMS rating is a verified, real-world specification.

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Key Specifications

• Channels: 1 (mono)
• Rated power: 300W RMS x 1 @ 4 ohms / 500W RMS x 1 @ 2 ohms
• Dynamic power: 333W x 1 @ 4 ohms / 647W x 1 @ 2 ohms (PowerCube)
• Bridgeable: No
• Circuit topology: Class D
• Efficiency (average): 89% @ 4 ohms
• Frequency response: 20Hz – 250Hz (+/-1dB)
• Input sensitivity: 150mV – 4V
• THD+Noise: <1.0% @ 4 ohms / <1.0% @ 2 ohms
• Crossover: Low-pass 50Hz–250Hz @ 12dB/octave Butterworth (on-board)
• Punch Bass EQ: 0dB to +12dB @ 45Hz
• Phase control: Variable 0° to 180°
• Signal input: High level (4-pin Molex) / Low level (1 x RCA pair)
• Signal output: 1 x RCA pass-through pair
• Remote control: Punch Level Control (PLC) — included
• Operating voltage: 9–16V DC
• Power wire gauge: 4 AWG
• Speaker wire gauge: 8 AWG
• Recommended fuse: 50A (not included)
• CEA-2006 compliant

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Features & Benefits

• Class-D Circuit Topology (89% Efficiency) — Class-D switching amplifiers are significantly more efficient than Class A/B designs. At 89% average efficiency, the R500X1D converts more input power into usable output, runs cooler, and places less load on the vehicle's electrical system — an important consideration in Australian summers where underbonnet and boot temperatures climb fast.
• 500W RMS in a Compact Chassis — At just 21.59 cm deep, the R500X1D is notably more compact than many Class A/B amplifiers producing similar power. Fitting into tighter enclosure locations is straightforward without sacrificing output — ideal for utes, wagons, and builds where space is limited.
• On-Board Punch Bass EQ (+12dB @ 45Hz) — Variable bass boost of up to +12dB centred at 45Hz allows precise low-frequency tuning directly from the amplifier. Dial in the right amount of punch to suit your enclosure type and listening preference — without an outboard equaliser.
• Variable Phase Control (0°–180°) — Unlike a fixed 0°/180° phase switch, the R500X1D offers continuous variable phase adjustment. This allows fine-tuned alignment between the subwoofer and main speakers across a range of installation positions — reducing bass cancellation caused by acoustic delay in larger vehicles.
• Remote Punch Level Control (PLC) — The included PLC mounts conveniently under the dash or in the centre console, linking directly to the gain control. Adjust subwoofer output on the fly without touching the amplifier — useful for road trips, different music genres, or passenger preferences.
• RCA Pass-Through Outputs — Signal can be chained to a second amplifier via the RCA pass-through, enabling clean two-amp builds without splitters or Y-adaptors. Designed for systems running a separate amplifier for mids and highs alongside the R500X1D for subwoofers.
• High-Level Inputs — Compatible with factory head units via a 4-pin Molex high-level input connector. No line output converter is required, making the R500X1D a straightforward upgrade path from factory audio.
• 12dB/Octave Butterworth Low-Pass Crossover (50Hz–250Hz) — Variable low-pass filtering ensures only bass frequencies reach the subwoofer. Adjustable between 50Hz and 250Hz to suit sealed, ported, or bandpass enclosure tuning.
• MOSFET Power Supply with Full Protection — Over-current and short-circuit protection, combined with a muted turn-on circuit, safeguard the amplifier and connected drivers. Real-time thermal sensing monitors both output stage and power supply temperatures and shuts down before damage can occur.
• CEA-2006 Compliant Power Ratings — The 500W RMS output is verified under the CEA-2006 measurement standard — a real-world, signal-referenced figure, not a burst or inflated peak specification.

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Technical Specs

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Compatible With / Goes Well With

The R500X1D is a dedicated mono subwoofer amplifier. Confirmed load configurations based on manufacturer specifications:

• Single 4-ohm SVC subwoofer (300W RMS rated output)
• Single 2-ohm SVC subwoofer (500W RMS rated output)
• Dual 4-ohm SVC subwoofers wired in parallel (presenting a 2-ohm load — 500W RMS)
• Dual 8-ohm SVC subwoofers wired in parallel (presenting a 4-ohm load — 300W RMS)
• Factory head units without RCA outputs (via high-level Molex input)

Goes well with:

• Rockford Fosgate Prime or Punch series full-range amplifier (for a complete two-amp system)
• Rockford Fosgate Prime or Punch series subwoofers (matched to 300W or 500W RMS ratings)
• Aftermarket head units with RCA preamp outputs
• Sealed or ported subwoofer enclosures tuned between 30Hz–60Hz

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Frequently Asked Questions

Why choose Class-D over Class A/B for a subwoofer amplifier?

Class-D runs at up to 89% efficiency, producing far less heat and drawing less current than a Class A/B amplifier of similar power. For subwoofer-only use in the 20Hz–250Hz range, Class-D is well-suited and the efficiency advantage is significant.

What subwoofers will the R500X1D run?

The R500X1D delivers 300W RMS into 4 ohms or 500W RMS into 2 ohms. Match your subwoofer's RMS power handling to the appropriate load configuration. Wiring dual 4-ohm SVC subwoofers in parallel presents a 2-ohm load for the full 500W output.

Is the R500X1D bridgeable?

No. The R500X1D is a single-channel mono amplifier and cannot be bridged. If higher output is required, consider a higher-rated mono amplifier from the Rockford Fosgate Punch or Power series.

Does it work with a factory head unit?

Yes. The R500X1D includes high-level inputs via a 4-pin Molex connector for direct connection to factory speaker wire outputs. No line output converter is needed for most standard factory installations.

What wiring do I need for installation?

The R500X1D requires 4 AWG power and ground cable, 8 AWG speaker wire, and a 50A fuse (not included). A Remote Punch Level Control is supplied. Professional installation is recommended to ensure correct earthing and fusing for a 500W amplifier.