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Rockford Fosgate M400-4D

400W RMS 4-Channel Full Range Class D Marine Amplifier

In Stock. Only 2 Left!
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List price $299.95

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$199.95

with warranty

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General Features:

  • 4-Channel Full Range Class D Marine Amplifier
  • RMS Power Rating:
    • 4 ohms: 75 watts x 4 chan.
    • 2 ohms: 100 watts x 4 chan.
    • Bridged, 4 ohms: 200 watts x 2 chan.
  • UV resistant and Salt-fog marine protection
  • Pulse Width Modulated MOSFET power supply
  • LED power (green) and protect (red) indicators
  • Variable Bass Boost (0 to +18 dB bass boost at 50 Hz)
  • Soft start turn-on
  • 4/3/2 channel operation
  • Preamp RCA output to daisy chain multiple amps
  • 3-way protection circuitry (thermal, overload, and speaker short protection)
  • High-density split-dome convection heat-sink for extreme heat dissipation
  • Nickel-plated RCA level inputs
  • Nickel-plated screw terminals
  • Input sensitivity:
    • Low level: 125mV-5V
    • High level: 250mV-10V
  • Variable high-pass filter (50-500 Hz, 24 dB/octave)
  • Variable low-pass filter (50-500 Hz, 24 dB/octave)
  • CEA-2006 compliant amplifier
  • Frequency response: 20-20000 Hz
  • 4 gauge power and ground wiring is required for installation. Contact us for information regarding a discount on select amplifier kits from our website when purchased together with this amplifier.
  • Dimensions: 6-7/10"W x 9-1/10"L x 2"H
  • 1-year SonicElectronix.com Warranty

Power Specifications - Full Range Channels

RMS Power @ 4 ohms

The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. It is the most accurate depiction of real, continuous power that the industry has so far.

If the final impedance of your speakers or subwoofers equals 4 ohms, this is how much power this amplifier will supply at that ohm level. The higher the RMS wattage, the more clean and loud your music will sound.

75 watts x 4 channels
RMS Power @ 2 ohms

The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. It is the most accurate depiction of real, continuous power that the industry has so far.

If the final impedance of your speakers or subwoofers equals 2 ohms, this is how much power this amplifier will supply at that ohm level. The higher the RMS wattage, the more clean and loud your music will sound.

100 watts x 4 channels
Bridged RMS Power

Bridging refers to combining two channels on an amplifier to create one channel with double the voltage and an increased power output. A 2-channel amplifier will bridge down to 1-channel and a 4-channel amplifier can bridge to create 2-channels. An amplifier is most commonly bridged to drive a subwoofer.

Remember, once you bridge two channels down to one its final impedance will be 4 ohms unless otherwise specified. This rating lists the RMS power created once an amplifier is bridged.

200 watts x 2 channels

Amplifier Specifications

Marine Certified
Marine certified means that the unit has been designed and manufactured with a marine use in mind. It will withstand the harsh conditions that come from marine use. Generally, they are treated against UV rays and treated with special protective coatings.
Yes
Amplifier Class

An amplifier increases the power of the signal being fed to it by taking energy from its power supply and matching the signal but increasing its amplitude. Amplifiers use many different methods for converting these electrical signals and have been categorized into classes.

Class A/B: Greater than 50% of the input signal is amplified while the other percentage is “off”. These amplifiers have a small amount of current flowing through the output transistors all the time which almost eliminates crossover distortion. Class A/B has great sound quality but is not as efficient as class D. These amps are most commonly used to drive speakers.

Class D: Also known as switching amplifiers, class D amps have output transistors that are completely turned “on” or “off”. This means that when the transistors are on, there is almost no voltage across them but when they are off there is significant voltage but no current flowing through it which makes these amplifiers very efficient at the cost of sound quality. These amps are most commonly used to drive subwoofers.

Other Classes: You may see classes such as GH, bD, X, FD, etc. by some manufactures. These amplifiers tend to be either class A/B, D or a hybrid of the two but with improvements to their designs that can make them more efficient or offer better sound quality.

D
Number of Channels
Each channel on an amplifier will power one speaker using a positive and negative cable. There are various types of amplifiers, each designed to power a certain number of speakers. Monoblock amplifiers, also known as single channel, are designed to power one or more subwoofers. These amplifiers often have very high power ratings. On the other hand, multi-channel amplifiers power multiple speakers, usually at lower power ratings. 2-Channel and 4-Channel amplifiers can power car speakers or low powered subwoofers. Occasionally you might see a 5 or 6-channel amplifier that can power speakers and subwoofers at the same time. The most common setup is a monoblock amp to run subwoofers and a 4-channel amp to run door speakers. Check out our Knowledge Base for more information.
4
Total RMS Power Output
Total RMS power is measured by multiplying RMS power per channel by the number of channels, and is calculated at the lowest level of operating impedance.

RMS power is the amount of continuous power, measured in watts, that an amplifier produces is called RMS power. The higher the RMS figure, the louder and cleaner your music sounds.

The RMS output figure is much more accurate than the peak rating when comparing products.

400 watts
Maximum Input Gauge Size
This is the largest gauge wire that will fit into the power and ground terminals of this device. The lower the gauge number, the thicker the wire is. For example, a 4 gauge wire is thicker than an 8 gauge wire and thus has higher current carrying capacity. Always do your best to get this size wire to reduce the risk of damage to your components.
4 AWG
Minimum Impedance Unbridged
The lowest impedance the amplifier will handle when it is not bridged.
2 ohms
Minimum Impedance Bridged
The lowest impedance the amplifier will handle when it is bridged.
4 ohms
Speaker Level Inputs
Speaker level inputs are commonly referred to as high-level inputs and vice versa. This input type allows you to get your audio signal directly from the speaker wire in your vehicle, instead of using RCA cables. The advantage of this is factory integration, as most stock radios do not have RCA outputs to run amplifiers.
No
Preamp Outputs
Many amplifiers are equipped with RCA preamp outputs which pass the original music signal from the source to additional amplifiers. This is known as daisy chaining because the source connects to the first amp, and the first amp connects to the second amp, etc. The advantage to daisy chaining is you only need one 2-channel RCA cable to transfer the signal from the head-unit to the amplifier, and then one additional cable for each amp being daisy chained.
1 pair
Built-in Crossover

A crossover is a type of filtering system that permits only certain frequencies to play. A Low-Pass (LP) crossover allows only frequencies below its setting to get through which is good in the case of some subwoofers. A High-Pass(HP) filter allows frequencies above its setting to pass through, this is normally used on speakers.

When a crossover is set to FULL it means no filtering is added and the full frequency spectrum is allowed through the amplifier. Filtering is important because feeding a speaker frequencies it cannot reproduce effectively creates distortion.

Low-pass (LP)
High-pass (HP)
High-Pass Crossover Frequency
The high-pass crossover frequency can be a fixed crossover point or a variable crossover range. A variable high-pass crossover allows you to select a specific crossover point which allows frequencies above the set crossover point to pass, while making frequencies below the set point gently or harshly roll-off, depending on the steepness of the slope.

The steepness of the roll-off slope is measured in dB/octave and refers to the rate of attenuation (lowering of volume) outside their pass bands.

50 - 200 Hz
Low-Pass Crossover Frequency
The low-pass crossover frequency is typically used for subwoofers. It can be a fixed crossover point or a variable crossover range. A variable low-pass crossover allows you to select a specific crossover point which allows frequencies below the set crossover point to pass, while making frequencies above the set point gently or harshly roll-off, depending on the steepness of the slope.

The steepness of the roll-off slope is measured in dB/octave and refers to the rate of attenuation (lowering of volume) outside their pass bands.

50 - 200 Hz
Bass Boost
The objective of the bass boost is to get more kick out of your subwoofer. It is a circuit that emphasizes the lower frequencies at a given point. The bass boost should always be set first before setting the gain. This feature is known for destroying subwoofers and is commonly used incorrectly, so be cautious.
0 - 18 dB
Bass/Gain Remote
If the amp comes with a bass/gain remote you will be able to control the level of your bass from your dashboard. Typically bass remotes also include a 16-20 ft. wire for installation.
No
Fan Cooled
A great feature to have if an amp generates a large amount of heat. Cooling fans can help regulate the temperature to prevent the amp from overheating (burning).
No
CEA-2006 Compliant
Amplifiers that have been tested to meet specific standards. When a car amplifier meets these standards, you can be sure that it will be able to produce the amount of power specified by the official CEA-2006 rating. Usually, these rating consist of the following items:
  • RMS Power
  • Signal-to-Noise Ratio

This rating applies to both external car amplifiers, as well as the amplifiers inside of in-dash stereos.

Yes

Specials with this Item

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Warranty and Return Policy

Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider
Sonic Electronix

Summary of Customer Ratings & Reviews

Rating Distribution

5 Star
100%
4 Star
0%
3 Star
0%
2 Star
0%
1 Star
0%

Average Attribution Rating

Durability
4.4
Value
4.8
Features
4.6
Design
4.6
Usability
4.8
Jacob

Louisville, KY

Overall
Durability
Value
Features
Design
Usability
Compact but Powerful

March 17, 2014

I bought this amp to put in a bass boat and I was very surprised when I opened the box. It's a very small amp and I had no problem mounting it where I wanted. It runs cool and powers my speakers with ease. My birth sheet said 507 watts.

0 of 0 found this helpful

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Ole school

Illinois

Overall
Durability
Value
Features
Design
Usability
Ole school

September 19, 2013

The ease of use and install, the look and design are awesome, the output is consistent and clear. I matched it with the rest of my Rockford Fosgate stereo. I am happy with it

0 of 0 found this helpful

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Randy

Fort Lauderdale, FL

Overall
Durability
Value
Features
Design
Usability
AWESOME!

September 12, 2013

This amp is AWESOME! Sounds great! Comes with a certification saying my serial unit was tested to 536 RMS. Would highly recommend.

0 of 0 found this helpful

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Gro

Thib, LA

Overall
Durability
Value
Features
Design
Usability
Good sound, small package

May 31, 2013

I have this amp pushing a pair of RF 262s and a pair of RF 282s. Much better sound than my previous MB Quart amp (and that one didn't sound bad either). Time will tell how it holds out - only 3 stars on durability because I have only had it for a few week no, but 0 issues.

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JayBee

Canada

Overall
Durability
Value
Features
Design
Usability
Real Good Amp

October 31, 2012

It's my first marine amplifier. I used it whole summer. Can drive it at max without over heating. The longer period I used it is about three hours at maximum volume and the battery is still good for start the motor. Use it bridge with two eight inches Rockford Fosgate M282.

I Really think it's a quality amp and would buy it again.

0 of 0 found this helpful

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Accessory Tools and Products

Accessories added

NVX XKIT42

Complete 4 Gauge Amp Wiring Kit with RCA Interconnect Cables and Speaker Wire!

Your Price $69.99

The InstallBay AK4 by Metra

4 Gauge Amplifier Installation Kit with RCA Interconnect Cable

Your Price $24.99

StreetWires ZN1K-04

4 Gauge (AWG) ZN1 Series Single Amplifier Installation Kit for Systems up to 1000 Watts

Your Price $49.95

Kicker Q-Series RCA Interconnect Cable

19 ft. of 4-Channel Q-Series RCA Cable with dual twisted-pair conductors, hyper-flex technology, and gold-plated k-cut collars for excellent signal transfer.

Your Price $59.95

Kicker 4-Channel RCA Audio Interconnect Cable

4 Meters (13 ft.) 4-Channel K-Series RCA Audio Interconnect Cable

Your Price $19.95

StreetWires ZN9 Series Interconnect Cable

16.4 ft. of 4-Channel RCA Cable with Rhodium-plated contacts and ZeroNoise construction for clear signal transfer!

Your Price $99.95

Monster Cable XLN 16 AWG Speaker Wire

16 Gauge Wire - 50 ft. of Dual Twist Speaker Cable with 4 Pairs of Speaker Terminals.

Your Price $29.95

StreetWires SCP1215BL - 12 AWG Speaker Wire

12 Gauge Wire - 15 ft. of Speaker Cable with Twisted Construction

Your Price $24.95

StreetWires FB4

4 AWG / 4 Gauge Firewall Bushing

Your Price $6.95

Car/Marine Audio Installation Kit

Includes Test Light, Crimp/Splice Tool, Multi-bit Screwdriver and more.

Your Price $14.99

Browse 1 question and 1 answer
Hide answersShow all answers | Sort by
will this amp work well with 2 polk audio mm521 and, 2 polk mm651 um on 20 ft. boat with possible sub in future if needed?
A shopper on Oct 20, 2014
Best Answer: Hello,

Yes, this amp will be a great match for the Polk Audio MM651 & Polk Audio MM521. Obviously being Four Speakers total, you will NOT be able to integrate a subwoofer, because the Four Channels on the amplifier will already be occupied.
Reply · Report · Customer SStaff on Oct 21, 2014
· Add Answer · I Have This Question Too (0)

Product Summary

Manufacturer

Model Number

M400-4D

UPC

780687340803

Weight

5.50lbs

Internal SKU

m4004d

Internal Product ID

43378

Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: Rockford Fosgate M400-4D