Rockford Fosgate R2-300X4 Prime 300 Watt 4-Channel Amplifier

Rockford Fosgate R2-300X4 Prime 300 Watt 4-Channel Class D Amplifier

When four speakers need real power without compromise, the R2-300X4 delivers 300 watts of clean, efficient Class D performance engineered by Rockford Fosgate.

Product Overview

The R2-300X4 is part of Rockford Fosgate's 3rd generation Prime Series, built for car audio enthusiasts who demand reliable, high-performance amplification at an accessible price. Operating as a full-range Class D 4-channel amplifier, it runs at 4 ohm or 2 ohm stereo and 4 ohm bridged/mono, giving it the flexibility to drive front and rear speaker pairs or reconfigure as a 3-channel or 2-channel setup. Class D topology maximises efficiency and reduces the electrical load on the vehicle's charging system, while MEHSA 4 (Maximum Efficiency Heat Sink Application) actively reduces MOSFET temperatures, lowers distortion, and prolongs output device lifespan. The top-mounted control panel provides independent front and rear controls within easy reach, and CTA-2006 compliant power ratings confirm that the 300W output is a real, tested figure. Designed and engineered in Tempe, Arizona, the R2-300X4 is built by fanatics, for fanatics.

Features & Benefits

C.L.E.A.N. Technology (Patent 8,712,066): Rockford Fosgate's patented Calibrated Level Eliminates Audible Noise circuit uses dedicated input and output clip LEDs (C.L.E.A.N. IN Red, C.L.E.A.N. OUT Blue/Red for both front and rear) to accurately match the source unit's output to the amplifier's input sensitivity, eliminating guesswork and reducing distortion at the source.

P.O.W.E.R. Supply: Onboard power supply design that continues to generate output above the rated RMS figure as vehicle voltage increases, so real-world performance scales beyond the spec sheet across the 9-16V operating range.

MEHSA 4 (Maximum Efficiency Heat Sink Application): An advanced thermal management system that reduces MOSFET operating temperatures, lowers distortion levels, increases overall durability, and extends the lifespan of output devices under sustained use.

NOMAD Protection: A real-time analogue computer that continuously monitors the amplifier's outputs and protects against shorting speaker wires and dangerously low speaker impedances, providing active fault management rather than passive fusing alone.

Balanced Differential Inputs: Differential input topology eliminates noise picked up by signal cables between the source unit and amplifier, delivering a cleaner signal into the amplifier stage.

Fully Adjustable Butterworth Crossovers: Independent front and rear 12 dB/octave High-Pass and Low-Pass crossovers, continuously variable from 50 to 250 Hz, with an All-Pass option per channel for full-range output when no filtering is needed.

High Level Input Capable: Accepts both low-level RCA (150mV-4V) and high-level speaker signals (450mV-12V) through a 2/4 Channel Input Selection Switch, making integration with factory head units straightforward.

Auto-Sense RAP Bypass: Auto-Sense bypass switch supports vehicles with Retained Accessory Power (RAP), allowing the amplifier to power on and off correctly using speaker-level signal detection without requiring a dedicated remote turn-on wire.

RCA Pass-Through Outputs: 2-channel RCA pass-through remains active with both RCA and high-level inputs, allowing downstream amplifiers to be added without splitting cables at the head unit.

CTA-2006 and CE Compliant: All power ratings verified at 14.4V with 1% or less THD to CTA-2006 industry standards, with no inflated peak figures used anywhere in the specifications.

Technical Specs

Goes Well With

The R2-300X4 pairs naturally with Rockford Fosgate Prime Series full-range speakers such as the R165X3, R168X2, R169X2, and R169X3 for a matched front and rear speaker setup. For systems requiring low-end support, the rear channels bridge cleanly to drive a single Prime R1 subwoofer such as the R1S410 or R1S412, with the rear crossover set to Low-Pass. A 4-gauge amplifier wiring kit is required for power and ground runs, and 8-gauge cable is needed for speaker outputs. A quality 4-channel RCA interconnect is recommended for clean signal transfer from the head unit.

Frequently Asked Questions

Can the R2-300X4 be used to power both speakers and a subwoofer in the same system?

Yes. The R2-300X4 supports 3-channel configuration, where the front channels power a pair of full-range speakers and the rear channels are bridged to drive a single subwoofer. Setting the rear crossover to Low-Pass rolls off high frequencies to the sub. The minimum impedance of any bridged channel is 4 ohms, so confirm subwoofer impedance before bridging.

Does the R2-300X4 require a remote turn-on wire?

When using RCA inputs, a remote turn-on wire must be connected to the head unit's remote output. When using high-level speaker inputs, the Auto-Sense bypass switch can be enabled to allow the amplifier to detect an incoming signal and power on automatically, making it compatible with factory head units and systems that lack a dedicated remote output, including those with Retained Accessory Power (RAP).

What does the NOMAD protection system do?

NOMAD is a real-time analogue computer built into the R2-300X4 that continuously monitors the amplifier's speaker outputs. It protects the amplifier from damage caused by shorted speaker wires and dangerously low speaker impedances, providing active, dynamic protection rather than relying solely on a fuse.

What gauge power, ground, and speaker wire does the R2-300X4 require?

Rockford Fosgate specifies 4 AWG for power and ground runs using the included compression terminal block connectors. Speaker output connections use 8 AWG wire. The recommended 60A fuse is not included in the box and must be sourced separately, installed as close to the battery as possible.

Can the R2-300X4 be bridged into a 2-ohm load for maximum power?

No. When bridging the R2-300X4, the minimum supported impedance per bridged output is 4 ohms. Running a bridged channel into a 2-ohm load is not supported and risks amplifier failure or NOMAD-triggered protection shutdown. In standard stereo mode, the minimum impedance per channel is 2 ohms.