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.
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
- 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.
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
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
front and rear channels. They are nickel-plated to resist signal degradation caused
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