100 Watts × 4 Channels at 2Ω Compact 4-Channel Amplifier for Front/Rear Systems and Front Stage with Rear Subwoofer.

Product Overview

The Rockford Fosgate Power T400-4 is a 4-channel amplifier delivering 100W into each of its four channels at 2Ω confirmed by Rockford Fosgate making it suitable for a full 4-way front and rear speaker system or a front stage and rear subwoofer configuration. The compact chassis with Dynamic Thermal Management is specifically designed for under-seat or space-constrained installation locations that full-size 4-channel amplifiers cannot accommodate.

Unlike the Class-AD T400X4AD which prioritises ultra-compactness for hybrid vehicles and UTVs the T400-4 is a full-featured conventional design with a MOSFET power supply and output stage, 4-gauge power and ground connectors, a 24dB/octave crossover, and a 2/4 channel input switch for flexible headunit integration. It is the choice when confirmed 100W per channel at 2Ω output is the primary specification requirement, and when the installation allows 4-gauge wiring for maximum power delivery.

Key Specifications

• Power output: 100W × 4 channels @ 2Ω (confirmed)
• Power output @ 4Ω: Not specified
• Bridged output: Not specified
• Configuration: 4-channel
• MOSFET power supply: Yes
• MOSFET output stage: Yes
• Crossover: 24dB/octave
• 2/4 channel input switch: Yes
• Power/ground connectors: 4 gauge
• Speaker connections: Audiophile grade
• Thermal management: Dynamic Thermal Management
• Chassis: Compact — under-seat installation capable
• Amplifier class: Not specified
• Signal-to-noise ratio: Not specified
• THD: Not specified
• Frequency response: Not specified
• Dimensions: Not specified
• Weight: Not specified
• Warranty: Not specified 

Features & Benefits

• 100W × 4 Channels at 2Ω — Confirmed Power Specification — Unlike many amplifier listings where per-channel power at a specific impedance is absent, Rockford Fosgate confirms 100W per channel into 2Ω on the T400-4. This gives the system designer a concrete figure to work with when matching the amplifier to 2Ω speaker loads. Power at 4Ω and bridged mono output should be confirmed from the official Rockford Fosgate datasheet.
• Front/Rear Fading or Front Stage Plus Rear Sub Configurations — The T400-4 is designed for two typical 4-channel setups: a full 4-way front and rear full-range speaker system, or a front stage component system with rear subwoofers driven from the rear channels. The 24dB/octave crossover and 2/4 channel input switch support both configurations without external signal processing.
• Dynamic Thermal Management for Compact Installation — Rather than a fixed protection shutdown at a temperature threshold, Dynamic Thermal Management actively manages the amplifier's output in response to temperature — reducing output as needed to prevent overheating in confined spaces. This allows the T400-4 to be installed under front seats, in centre consoles, or in other space-constrained locations where heat dissipation is limited.
• MOSFET Power Supply and Output Stage — MOSFET-based design in both the power supply and output stage provides clean, efficient power delivery and responsive switching — the same proven technology used across the Rockford Fosgate Power series.
• 24dB/Octave Crossover — Steep crossover slope for precise frequency band separation — enabling high-pass filtering on front stage speakers and low-pass filtering on rear subwoofers, or full-range pass-through for a standard 4-way system.
• 2/4 Channel Input Switch — In 2-channel mode, a stereo input is internally distributed to all four output channels — allowing connection to head units with only a 2-channel RCA preamp output. In 4-channel mode, discrete front and rear RCA inputs allow independent level control.
• 4 Gauge Power and Ground Connectors — Appropriate wiring infrastructure for a 400W 4-channel amplifier, ensuring the power delivery path matches the amplifier's output capability.
• Audiophile Grade Speaker Connections — High-quality output terminals for a solid, low-resistance connection to speaker voice coils across all four channels.

Technical Specs

Compatible With / Goes Well With

Suitable system configurations:

• Full 4-way front and rear speaker system (full-range crossover setting)
• Front stage component speakers (high-pass) + rear subwoofers (low-pass via crossover)
• Under-seat, centre console, or space-constrained installations where Dynamic Thermal Management allows reliable operation

Comparing T400-4 vs T400X4AD:

• T400-4: Confirmed 100W×4 @ 2Ω, 4-gauge wiring, Dynamic Thermal Management, conventional design — suited to standard car audio builds with 4-gauge wiring infrastructure
• T400X4AD (Class-AD): Ultra-compact, 8 AWG wiring, high-level auto turn-on, C.L.E.A.N. clip detection, PLC2 remote — suited to hybrid/EV, UTV, motorcycle, and OEM integration builds

Pairs well with:

• Rockford Fosgate or aftermarket component front speakers (4Ω or 2Ω)
• Rear subwoofers or coaxial speakers for the rear channels
• 4-gauge amplifier wiring kits
• Rockford Fosgate or aftermarket 4-channel RCA cables

Frequently Asked Questions

What is the confirmed power output of the T400-4?

Rockford Fosgate confirms 100W per channel into 2Ω, for a total of 400W across four channels. Power output at 4Ω and the bridged mono output rating are not confirmed in the supplier data — pull the official T400-4 datasheet for the full power specification table.

What does Dynamic Thermal Management mean for installation flexibility?

Dynamic Thermal Management actively reduces amplifier output as temperature rises — rather than a hard shutdown — allowing the T400-4 to sustain operation in confined spaces like under front seats where heat dissipation is limited. The amplifier trades peak output for continuous operation in hot or restricted environments.

What is the difference between the T400-4 and the T400X4AD?

Both are Rockford Fosgate Power series 400W 4-channel amplifiers. The T400-4 is a conventional design with confirmed 100W×4 @ 2Ω, 4-gauge connectors, and Dynamic Thermal Management. The T400X4AD is the Class-AD ultra-compact variant with 8 AWG connectors, high-level auto turn-on, C.L.E.A.N. clip detection, and specific design for hybrid vehicles, UTVs, and motorcycles. The right choice depends on your installation environment and integration requirements.

Can the T400-4 run both front speakers and rear subwoofers simultaneously?

Yes. This is one of the T400-4's designed use cases — front channels in high-pass mode driving component speakers, rear channels in low-pass mode driving subwoofers. The built-in 24dB/octave crossover provides the frequency separation required for this configuration without external processing.

What gauge wiring does the T400-4 require?

The T400-4 uses 4-gauge power and ground connectors. A minimum of 4-gauge cable is recommended for the power and ground runs. Confirm the specific cable length and fuse requirements for your installation with Rockford Fosgate's wiring guide or your installer.