Alpine MRX-M240

X-Power Series mono subwoofer amplifier — 2,400 watts RMS x 1 at 2 ohms

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  • Alpine MRX-M240


  • Alpine MRX-M240

  • Alpine MRX-M240

  • Alpine MRX-M240

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Item #: 500MRXM240

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Our take on the Alpine MRX-M240

by Buck Pomerantz

My system has plenty of power. Who needs an amp?

You might think you don't need an amp because you have a 400-watt system in your car, or because your new stereo puts out 50 watts a channel. But those are peak wattage ratings, which may boil down to 15 or 20 watts per channel, using the more realistic RMS rating. An amp sends your speakers the power they need to deliver your music with clarity and impact, whether you're using factory speakers or high-performance components. And low-frequency reproduction requires lots of power, so an amp is an absolute must if you're adding a sub to your system.

Alpine Authorized Online Dealer

Digital technology that sounds perfect

Alpine's X-Power MRX-M240 mono amplifier uses the latest amp technology to play your music loud and clean without taking up much space. And this amp employs some of the same circuitry developed for Alpine's top-of-the-line PDX digital amps, so it'll bring exceptional sound to almost any ride.

Massive power for high-level systems

The MRX-M240 puts out up to an astonishing 2,400 watts RMS to your subwoofer system, perfect for competitors and true bassheads. And it'll operate safely with a 1-ohm load, making it useful in a variety of sub system installations. Onboard low-pass and subsonic filters let you get the best sound out of your setup, while a parametric bass boost helps to fatten up the sound at exactly the right notes, if you need it.

Looks cool too

A power management system optimizes the amp's performance and keeps the music playing, even when you're pushing it hot and hard for a long time. Speaker-level inputs with an automatic turn-on feature simplify system hook-up.

MRX-M240 control panel
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  • mono subwoofer car amplifier
  • 1,500 watts RMS x 1 at 4 ohms (2,400 watts RMS x 1 at 2 ohms)
  • 1,000 watts RMS x 1 at 1 ohm
  • CEA-2006 compliant
  • variable low-pass filter (50-400 Hz, 24 dB/octave)
  • variable bass boost (0-12 dB at 30-80 Hz)
  • variable subsonic filter (5-30 Hz, 24 dB/octave)
  • optional remote level control (RUX-KNOB)
  • Class D amp with MOSFET power supply
  • preamp and speaker-level inputs
  • preamp outputs
  • fuse rating: 175A x 1
  • 1/0-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 18-1/8"W x 2-5/16"H x 9-1/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

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

Features and Specs
RMS Power Output (Watts x Channels) 1500 x 1
Peak Power Output (Watts x Channels) 2400 x 1
Power at 2 Ohms (Watts x Channels) 2400 x 1
Bridged Power (Watts x Channels) ---
Minimum Impedance Bridged ---
Minimum Impedance Unbridged 1
Best Frequency Response 5-400 Hz
THD at Rated RMS Power 1%
Signal to Noise Ratio 82 dB
Input Voltage 14.4v
Amplifier Class D
Low-Pass Crossover Frequency 50-400 Hz
Low-Pass Slope (dB/octave) 24 dB/oct
High-Pass Crossover Frequency N/A
High-Pass Slope (dB/octave) N/A
Bass Boost 0-12 dB
Bass Boost Frequency 30-80 Hz
Fan Cooled No
Fuse Rating 175
Speaker Level Inputs Harness
Preamp Outputs 1 pair
Width (inches) 18-1/8
Height (inches) 2-5/16
Depth (inches) 9-1/16
Parts Warranty 1 Year
Labor Warranty 1 Year
Product Research
What's in the box?

Download owner's manual

  • Mono amplifier with a 175A Mega fuse installed
  • Left plastic terminal cover
  • Right plastic terminal cover
  • 4 Terminal cover screws (M3 x 10mm)
  • 4 Self-tapping screws (M4 x 20mm)
  • 2.5mm Allen wrench
  • 5mm Allen wrench
  • 7" Speaker-level input harness
  • Owner's Manual (Eng/ Fren/ Span)
  • Warranty sheet
  • Online registration card
  • Alpine 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.



MRX Amplifier Design: Class-D amplifiers boast higher efficiency, produce less heat, and draw less current than traditional Class-AB amps. The MRX series benefits from the technology trickledown from Alpine's more expensive PDX amps, including Direct FET final outputs, thermal management processor, 6-Layer Glass Epoxy PC Board; combining to create a high-end sound quality without the bulky heat sinks required by most amps in this power class.

STAR Topology: Alpine's unique STAR (Signal Transit for Accurate Response) Circuit PCB design provides a single common ground for all amp sub-blocks, preventing ground interference and minimizing internal noise.

Power Management Processor: The multi-stage Power Management Processor continuously monitors component temperatures throughout the amplifier and decreases power output if anything gets too hot. When playing music under heavy loads for long periods, the circuit automatically reduces power output slightly at first, and then further in a second stage if necessary. This two stage approach provides an interruption free listening experience.

CEA 2006 Compliant: The MRX-M240's power ratings are measured according to the Consumer Electronics Association CEA-2006 standards. These standards allow you to accurately compare the rated power output of all CEA 2006-compliant amplifiers, even different brands. Manufacturers who adhere to the standards can display the CEA 2006 logo on their products and packaging. The power output is measured from 20 Hz to 400 Hz using a 14.4 volt power supply with no more than 0.01% THD+N:

  • 4-ohm: 1500 watts
  • 2-ohm: 2400 watts
  • 1-ohm: 1000 watts

Signal-to-Noise: When measured under CEA-2006 conditions (reference 1 watt into a 4-ohm load) the signal to noise ratio is 82 dBA. Measured at the rated power output S/N is 108 dB.

Verification Certificate: The amplifier comes with a certificate that lists the RMS power output measured from that specific amplifier. It also lists the model number, serial number, test date, and the test conditions (voltage and impedance).

Auto Turn On: When using the speaker level inputs the X-Power amplifiers automatically turn on when voltage is detected on the signal inputs, making them an easy factory system upgrade.

Low Output Impedance: With low output impedance, the MRX-M240 outputs tightly controlled bass, with a damping Factor rated at greater than 1000.

LED: The top panel LED power indicator glows blue when the amplifier is turned on.


Gain: The MRX-M240's gain is set according to the level of the incoming signal. The line-level input gain setting is continuously variable from 100 mV to 4.0V; the speaker-level input gain setting is continuously variable from 250 mV to 10.0V.

Crossover: The low-pass crossover point is continuously variable from 50 to 400 Hz and the slope is 24 dB/oct; the crossover cannot be bypassed.

Subsonic Filter: The amp also has a 24 dB/oct subsonic filter, continuously variable from 5 to 30 Hz.

Bass EQ: Bass boost can be applied to the subwoofer output; it's variable from 0 to +12 dB with a variable center frequency of 30-80Hz.


Power/Ground/Remote: The MRX-M240 features set-screw terminals for the Power, Ground and Remote Turn-on inputs. The Power and Ground terminals will accommodate up to 1/0 gauge wire, and the Remote Turn-on terminal will accept up to 8 gauge wire.

Speaker Output: The speaker outputs terminal is also set-screw terminals and will accept up to 8 gauge wire.

Line Input/Output: Line level RCA is the preferred input connection. The full range stereo line output allows easily adding another amp without running a second set of cables.

Speaker Level Input: Use the included speaker level input harnesses if the connected radio has no preamp outputs.

Fuses: The amp is protected by a chassis-mounted 175-amp Mega fuse.

Remote Bass Control (optional): Alpine's RUXKNOB wired remote (sold separately), connects to the amp's RJ-25 Remote Bass Control jack, and offers control of the subwoofer output level from the front of your vehicle. The linear attenuation can be adjusted from 0 to -20dB.

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Alpine MRX-M240 Reviews

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5 out of 5


Written By ededdy55, St. Paul,MN on Thursday, September 25, 2014
Crutchfield Customer Review (What's this?)
I love it. It has a lot of power for being small and light.
As I wrote, small, powerful and light weight.
Was this review helpful?    Yes | No
5 out of 5

Alpine MRX-M240

Written By Kevin K, Madison, WI on Sunday, September 07, 2014
Crutchfield Customer Review (What's this?)
Honestly I think everyone knows that Alpine makes awesome amplifiers. I have a Cadillac STS with (2) Orion 12" HCCA Competition dual 4 ohm 2000 watt RMS 4000 watt peak subwoofers each with their own MRX-M240 running at 2 ohms at the moment. I also have had them pound many other different subs out there, but when you see these speakers with their 445 ounce magnets being easily powered by these amps I am sure it would make you a believer! One certificate rates the amp at 2760 watts at 2 ohms and the other amp's certificate tested in at 2956 watts at 2 ohms. I mean these speakers are literally almost 70lbs each and absolutely demand and need a ton of power to perform and these amps do it with ease. I have 100% confidence these amps can power any sub out there. So if you want real, serious power here you go....for a very good price. Honestly I can't imagine having any more power as I have yet to meet someone that can actually crank this system and actually endure it for more than a couple minutes because of the extreme pain in your ears- so do you really need any more power? I think that basically sums it up, this amp is POWERFUL and can do the job.
best of the best
1 out of 1 people found this helpful
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5 out of 5

Alpine MRX-M240

Written By Anonymous, South Bend, IN on Monday, May 26, 2014
Crutchfield Customer Review (What's this?)
Got a great deal on this not to mention a lot of power.
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5 out of 5

Alpine mrx m240

Written By Pacman, Wasilla ,Ak on Friday, August 09, 2013
This amp is a beast!!! I have it on 4 t1 12s @ 2 ohms and ?????? .... Getting 157.6 dbs
Tons of power & versatile ohm loads with 1 ohm being 1000 rms and 2 being 2400. My sheet rates mine @ 2606@ 2 ohm.
This thing is power hungry. Do not buy this amp if you don't have your big 3 and @ least 3 deep cell batteries with your h.o alternator
1 out of 1 people found this helpful
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5 out of 5

best ive ever had

Written By mrboombastic, ventura California on Saturday, September 29, 2012
I have the alpine mrx m240 paired with two alpine type X's that 3000 watts each ...if your looking for something that handle any subs you throw at it ..this is the amp there is so much power that i fear to turn it up all the way it makes you feel like your in a tornado it really gets your blood pumping if you have the money spend it you won't be disappointed
Can handle any subs you throw at it
Requires alot of power and tends to make your headlights flicker
3 out of 4 people found this helpful
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1 question already asked

Is the mrx-m240 amp two big for the 12 in l7s DVC 2ohms? [ t  May 02, 2014 ]
1 answer
  • For details on fit or installation please contact an Advisor by phone (1-800-324-9695) or online chat. They will be able to pull up your vehicle and give you the details on if this will fit and what you will need for an installation in your vehicle. [ Greg Staff  May 02, 2014 ]

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For a more in-depth review and enhanced detailed information on the Alpine MRX-M240, please visit the Crutchfield website product page (/ISEO-rccbcspd/p_500MRXM240/Alpine-MRX-M240.html ).