1-888-955-6000
crutchfield.com
Crutchfield

Rockford Fosgate M400-4D

4-channel marine amplifier — 75 watts x 4 channels

Zoom
  • Rockford Fosgate M400-4D

    Front

  • Rockford Fosgate M400-4D

  • Rockford Fosgate M400-4D

  • Rockford Fosgate M400-4D

 

Our take on the Rockford Fosgate M400-4D

by Ken Nail
Rockford Fosgate

High power from a compact amp

Rockford Fosgate M400-4D marine amplifier

Rockford Fosgate's compact marine amplifiers provide high-efficiency Class-D power for your marine audio system. They meet tough UV and Salt-Fog protection standards, so you can install them with confidence in your pleasure craft, whether you're blasting across inland waterways, or cruising out to your favorite salt-water fishing grounds.

Power your speakers or subs

The M400-D4 4-channel amp delivers the power you need to drive two pairs of full-range speakers in your boat, sending 75 watts continuous power to each speaker. If you want to power a pair of subs, you can bridge the amp to 2-channel mode, sending 200 watts to each subwoofer — plenty of kick if you want some bass on board.

The amp features variable frequency filters to adjust the amp's output to your system, whether you're running full-range speakers or subs. And the compact footprint makes it easy to mount the amp in a small storage locker or other tight spot.

M400-4D connection panel See more info on this item

Highlights:

  • 4-channel marine amplifier
  • 75 watts RMS x 4 at 4 ohms (100 watts RMS x 4 at 2 ohms)
  • 200 watts RMS x 2 in bridged mode (4-ohm stable in bridged mode)
  • conformal-coated circuit board and UV-resistant finish
  • variable high- and low-pass filters (50-500 Hz, 12 dB per octave)
  • variable bass boost (0-12 dB at 45 Hz)
  • three auto-turn on modes
  • CEA-2006 compliant
  • preamp-level inputs and outputs
  • 4-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 9-1/8"W x 2"H x 6-7/8"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

Hands-on research from the Crutchfield Labs (what are the Labs?)

Features and Specs
Performance
RMS Power Output (Watts x Channels)
Loading...
75 x 4
Frequency Response at Rated RMS Power
Loading...
20-20k Hz
THD at Rated RMS Power
Loading...
1%
Signal to Noise Ratio
Loading...
70 dB
Input Voltage
Loading...
14.4v
Peak Power Output (Watts x Channels)
Loading...
---
Power at 2 Ohms (Watts x Channels)
Loading...
100 x 4
Bridged Power (Watts x Channels)
Loading...
200 x 2
Minimum Impedance Bridged
Loading...
4
Minimum Impedance Unbridged
Loading...
2
Features
Amplifier Class
Loading...
D
Low-Pass Crossover Frequency
Loading...
50-250 Hz
Low-Pass Slope (dB/octave)
Loading...
12 dB/oct
High-Pass Crossover Frequency
Loading...
50-250 Hz
High-Pass Slope (dB/octave)
Loading...
12 dB/oct
Bass Boost
Loading...
0-18 dB
Bass Boost Frequency
Loading...
45 Hz
Fan Cooled
Loading...
No
Fuse Rating
Loading...
40
Speaker Level Inputs
Loading...
No
Preamp Outputs
Loading...
1 pair
Height (inches)
Loading...
2
Width (inches)
Loading...
9-1/8
Depth (inches)
Loading...
7-7/16
Parts Warranty
Loading...
1 Year
Labor Warranty
Loading...
1 Year
Product Research
What's in the box?

Download owner's manual

  • 4-Channel marine amplifier
  • 3mm Hex key
  • 4 Self-tapping screws (length=1-5/8")
  • Installation & Operation Manual
  • Amplifier Verification Certificate

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team — they open the box, verify contents, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Features
Controls
Connections

Features

Overview: The Rockford Fosgate Prime Marine M400-4D is a 4-channel full-range Class D marine amplifier. It is optimized to power a full-range front/rear speaker system. You can also bridge the front and/or rear channels to run a subwoofer or two. The Class D design is very efficient with a cast aluminum heatsink to keep it in a small footprint.

Marine Amplifier: The M400-4D is designed for the harsh marine environment. The amplifier features a conformal-coated PCB and UV-resistant finish, and conforms to UV and Salt-Fog protection standards.

CEA-2006 Compliant: CEA-2006 is a system of testing and measurement methods for mobile audio amplifiers. This voluntary standard advocates a uniform method for determining an amplifier's RMS power output and signal-to-noise ratio. The criteria for measuring power uses a DC input voltage of 14.4 volts and the RMS power output is measured into a 4-ohm load with 1% or less Total Harmonic Distortion plus noise (THD+N). Signal-to-Noise ratio is measured in weighted absolute decibels (dBA) at a reference of 1 watt into 4 ohms. CEA-2006 allows consumers to compare amplifiers and receivers on an equal basis. The CEA-2006-rated RMS power output is as follows (measured with a 14.4 volt input, <1% THD+N, 20 Hz-250 Hz):

  • 4-Ohm: 75 watts x 4
  • 2-Ohm: 100 watts x 4
  • Bridged (4-Ohm): 200 watts x 2

LED Indicator: The amplifier is equipped with a top-mounted LED indicator which illuminates blue when the unit is turned on. The LED illuminates red when a protection circuit engages (short circuit or too low an impedance is detected at the speaker connections). The amplifier automatically turns off if this occurs.

Mounting: The amplifier can be mounted vertically, horizontally, or inverted using the supplied mounting screws; horizontal mounting (right side up) will provide the best cooling.

Controls

Independent Controls: The M400-4D has independent, top-mounted controls for the front and rear channels. The controls include:

  • Gain Control: The amplifier has rotary gain controls (0 to 11) for front and rear channels.
  • Crossovers: The amplifier features independent Butterworth crossovers for the front and rear channels. Each crossover can be set for low-pass, high pass, or all-pass (full range). The crossover frequency is continuously variable from 50-250 Hz with a slope of 12 dB per octave.

Punch EQ: The rear channel has an independent Punch EQ (bass boost) control that works with the crossover switch. When the rear channel crossover is set to low-pass, the Punch EQ can add a bass boost, centered at 45 Hz, from 0 dB to +18 dB.

2/4 CH Switch: When the 2/4 CH switch is set to the 2 CH position, the inputs are switched to a 2-channel mode. The signal on the front input feeds all four output channels, however, you lose front to rear fading capability. In the 4 CH position, the amp uses both front and rear inputs and fading capability is restored.

Connections

Power Terminals: The power and ground terminals are nickel-plated set-screw terminals, and will accommodate up to 4-gauge wire. The set screws can be tightened/loosened with the supplied 3mm hex key.

Fuses: The amplifier does not have on-board fuses. A 40A fuse should be placed on the power wire within 18" of the battery.

Remote Turn-On Terminal: The remote turn-on terminal is a nickel-plated set-screw terminal that will accommodate up to 8-gauge wire. The set screws can be tightened/loosened with the supplied 3mm hex key.

Speaker Terminals: The speaker terminals are nickel-plated set-screw terminals that will accommodate up to 8-gauge wire. The set screws can be tightened/loosened with the supplied 3mm hex key.

RCA Input Jacks: There are two pairs of RCA input jacks for the front and rear channels. They are nickel-plated to resist signal degradation caused by corrosion.

RCA Pass-Thru Jacks: The nickel-plated RCA pass-thru jack provides a convenient source for daisy-chaining an additional amplifier without running an extra set of RCA cables from the front of the vehicle to the amplifier location.

 
Review this product
Great Gear Giveaway rewards card

Submit a review and then enter to win a $500 rewards card

Rockford Fosgate M400-4D Reviews

Average Customer Review:

3 people say:

Review this product:

Thanks for taking the time to share your experiences about this product. Please be sure to focus your comments on the product itself. Read our Review Guidelines for more information.

Your email won't be visible. Please use the email address that is associated with your order.
(e.g., JohnD) Your review will be signed using the display name and location
(e.g., Charlottesville, VA)

Click on a star to rate the overall product on a scale of 1-5
1500 characters left
Attach a YouTube Review
Crutchfield Video Review Guidelines
  • Only submit videos that you made or are authorized to use.
  • Do not submit videos that contain music, video or visuals that are copyrighted and belong to someone else.
  • Please see our Review Guidelines for more information.
500 characters left
500 characters left
Filter by rating:
5 out of 5

Fosgate Amp

Written By TEDIII, Nashville on Tuesday, May 21, 2013
Crutchfield Customer Review (What's this?)
 
Great amp. Easy install. Actually came certified it tested at 553 amps. Would buy again.
Pros:
Solid product, small footprint, easy to install
1 out of 1 people found this helpful
Was this review helpful?    Yes | No
 
5 out of 5

Rockford Fosgate M400-4D

Written By Nicholas L, Birmingham, AL on Saturday, May 11, 2013
Crutchfield Customer Review (What's this?)
 
Perfect match for the 4 JL Audio 6.5s it's working, amp is easily tuneable, doesn't get hot in my dry storage, can blast music all day and the amp never gives up.
Pros:
Compact, easily tuneable, and can't seem to overwork amp.
1 out of 1 people found this helpful
Was this review helpful?    Yes | No
 
5 out of 5

rf m400 4d

Written By bob, omaha ne on Friday, June 29, 2012
Crutchfield Customer Review (What's this?)
 
good sound and output, runs way cooler than the 2 amps next to this one.and smaller
1 out of 3 people found this helpful
Was this review helpful?    Yes | No
 

1 question already asked

Can i use this as a 3 channel amp, powering a set of JL 7.7s and a sub? please let me know thanks [ Brent  Aug 01, 2014 ]
4 answers
  • I bought this amp but unfortunately havent had the time to install it. I plan to use the same 3 channel setting. I think that as long as you keep the same ohms and avoid overheating, you should have no problem. [ ANTONIO   Aug 02, 2014 ]
  • Yes, just wire the 7.7s to the two front channels then wIre the subs to one of the rear channels and leave the other channel empty. Or you could try running double wires from the rear channels to the sub get more power. [ jeff st   Aug 01, 2014 ]
  • Yes I would say you could as long as the amp has enough power for what your speakers and sub are rated for. Just check to make sure the amp can produce enough power for what your running. [ CAREY R   Aug 01, 2014 ]
  • Thanks for your question. For information on selecting the best amp for your subs I would recommend reaching out to an Advisor by phone (1-800-324-9695) or online chat. They will be able to help determine the differences between the amp models and help you make the best choice for your system. [ Greg Staff  Aug 01, 2014 ]

Add accessories for the Rockford Fosgate M400-4D

Build your system for great sound, maximum durability, and safe operation on the water. See all categories & accessories

T-Spec Power/Ground Cable Available by the foot in pearl or gray — marine-certified (4-ga. Pearl)
3 people say
Your Price: $3.99
Add to Cart
JL Audio XM-WHTSC16 Speaker Wire 16-gauge marine speaker wire — priced per foot
14 people say
Your Price: $0.49
Add to Cart
JL Audio Marine Y-adapter Cables 18" long (1 female RCA to 2 male RCA)
Your Price: $9.99
Add to Cart
JL Audio Marine Y-adapter Cable 18" long (1 male RCA to 2 female RCA)
Your Price: $9.99
Add to Cart
Your Price: $69.95
Add to Cart

Why choose SquareTrade?

The #1-Rated Protection Plan

Thousands of people have reviewed SquareTrade Protection Plans — and made us #1.

5-Day Service Guarantee & Free Shipping

We'll repair or replace your item in five business days or less after we've received it, or your plan is free. And, as always, we pay for all shipping.

Protection from Normal, Everyday Use

Repairing your average mechanical or electrical failure can cost as much as buying a new device. With SquareTrade, you're covered — including parts and labor.

For a more in-depth review and enhanced detailed information on the Rockford Fosgate M400-4D, please visit the Crutchfield website product page (/ISEO-rccbcspd/p_575M4004D/Rockford-Fosgate-M400-4D.html ).