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Terminator Series 8" compact powered under-seat subwoofer enclosure

Item # 236TN8MS

When you need lots of boom but only have a little room, this TN8MS sub gives you the sound you want in a compact...

When you need lots of boom but only have a little room, this TN8MS sub gives you the sound you want in a compact...

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Temporarily out of stock

Ship date unknown


Other options

About the MTX TN8MS

Small enclosure, impressive bass

When space inside your vehicle is limited, it can be difficult to find room for a subwoofer. MTX has solved this problem by creating a shallow-mount powered sub that fits in cramped confines to give you impressive bass without taking up a whole lot of space.

Small enclosure, impressive bass

When space inside your vehicle is limited, it can be difficult to find room for a subwoofer. MTX has solved this problem by creating a shallow-mount powered sub that fits in cramped confines to give you impressive bass without taking up a whole lot of space.

So easy to fit

MTX designed their TN8MS powered subwoofer to deliver high-quality bass response in an enclosure small enough to fit your vehicle's nooks and crannies. At only 3" high, this sub will fit under most seats and behind many truck seats. With a built-in amp that delivers 135 watts RMS to the low-profile 8" sub, you'll get the rich, full bass you need in a simple, easy-to-fit package.

Tune it to your tastes

You'll also get a full control set to tune your low end to your music and your tastes. A variable low-pass crossover lets you set the frequency anywhere from 50 Hz to 150 Hz so you can adjust the sound to best complement your speakers. The bass boost control gives you up to +12 dB of boost at 45 Hz, and the phase switch allows additional adjustment to dial in your system. A wired remote control connects to the sub via a 3.5mm cable, letting you adjust the bass response from the driver's seat. 

Secure and connected

The TN8MS features speaker-level and line-level inputs so you can run the sub directly from your car stereo, or get a signal from your speaker wiring. The high-density aluminum enclosure keeps the sub and amp safe from thumps and bumps, and the metal grille protects the speaker.

When you need lots of boom but only have a little room, the TN8MS gives you the sound you want in a compact package with easy installation and great sound.


Product highlights:

  • powered subwoofer with high-density aluminum enclosure and metal grille
  • 8" shallow-profile woofer
  • Class A/B amplifier: 135 watts RMS (200 watts peak)
  • low-pass crossover variable from 50-150 Hz
  • includes wired remote bass level control
  • speaker and line-level inputs
More information:
  • bass boost (0 to +12 dB at 45 Hz)
  • phase switch (0°, 180°)
  • frequency response: 20-200 Hz
  • sensitivity: 91 dB
  • requires 8-gauge wiring kit with 15-amp fuse (sold separately)
  • dimensions: 13-15/16"W x 3-1/4"H x 9-5/8"D
  • warranty: 2 years
  • Our 60-day money-back guarantee
  • MFR # TN8MS

What's in the box:

  • Amplified enclosure with one 8" subwoofer installed
  • 10" Speaker level input harness
  • 15-amp ATO fuse (installed)
  • Remote level control with 13' cable attached (3.5mm mini-plug on the end)
  • Adhesive mounting pad (to mount the remote)
  • 4 Mounting brackets
  • Four 3/4" Pan head screws
  • Eight M3x6mm Machine screws
  • Owner's manual (English/ Spanish/ Portuguese/ French)

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Crutchfield response

<< >>

More details on the MTX TN8MS

Pat M.

Features & specs

Enclosure Type Sealed
Finish Material Aluminum
Grille Steel
Connector Type RCA, Harness
Bi-amp Inputs No
Woofer Size (inches) 8
Woofer Material
Passive Radiator ---
Width 9-11/16"
Height 3-1/4"
Depth 14"
Second Depth N/A
Parts Warranty 2 Years
Labor Warranty 2 Years
Frequency Response 20-200
Amplifier Power (RMS) 135 watts
Maximum Wattage 200 watts
Sensitivity 91 dB
Impedance ---
Second Voice Coil Impedance ---
Crossover Point 50-150 Hz

Product Research


CTA-2006 Compliant: CTA-2006 is a system of testing and measurement for mobile audio amplifiers. This voluntary standard advocates a uniform method for measuring an amplifier's RMS power output and signal-to-noise ratio. The criteria for measuring amplifier power uses a DC input voltage of 14.4 volts and the RMS power output is measured over a frequency range of 20 Hz to 20 kHz (for full range amplifiers), 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. CTA-2006 standards allow consumers to compare car amplifiers and receivers under the same conditions (apples to apples).

CTA-2006 Specifications:

  • Power Output: 135 watts RMS x 1
  • Signal to Noise Ratio: 91 dBA

Auto Turn-on: If using the speaker level input, an automatic circuit turns the amplifier on when it senses an input signal. When using the line level inputs you must also use a remote turn on lead.

Speaker Level Input: A 10" speaker level input harness is included, making it easier to add the amplifier to a factory radio or to a receiver with no preamp outputs.

Wired Remote: Using the included wired remote you can easily adjust the output level from the driver's seat (or wherever you mount the remote).


  • Gain: rotary control; variable from 400mV-5 volts
  • Bass Boost: rotary control; variable from 0 to +12 dB; boost centered at 45 Hz
  • Low Pass X-Over: rotary control; variable from 50-150 Hz
  • Phase: two position switch; 0° or 180°


  • Power:
    • +12 volts: set screw terminal; accepts up to 8-gauge wire; 8-gauge minimum is recommended
    • Ground: set screw terminal; accepts up to 8-gauge wire
    • Remote Turn-on: set screw terminal; accepts up to 8-gauge wire
  • RCA: left and right line level inputs
  • High Input: speaker level input; 10" harness included
  • Remote: 3.5mm mini-jack for use with the included wired remote

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Customer Q&A

Crutchfield asked: Why did you buy this?
Quality product, great price. [ David  May 04, 2020 ]
it was the best option for my given situation(small car that I will not have forever, but did not want to upgrade for permanency until I get my permanent car. [ Jt  Feb 29, 2020 ]
will fit perfectly in my 1990 ZR1 corvette [ George  Feb 23, 2020 ]
It is the perfect addition to my sons system and as always Crutchfield had what I needed [ Jason  Dec 01, 2019 ]
Video and brand rep [ Samantha  Sep 20, 2019 ]

4 questions already asked

Will this fit in a Lotus Elise?
[ Juhee  May 10, 2020 ]
1 answer
We have not received any answers from other customers on your question. I would recommend reaching out to an Advisor by phone (1-800-324-9695) or online chat. They should be able to help answer your question.
[ Calvin  May 27, 2020 ]  Staff
Can you install 2?
[ John  Feb 25, 2020 ]
2 answers
Possibly - I would be concerned primarily with power requirements of 2, then secondarily, about phase. If you install 2, (presumably under your two from seats), one would likely need to be out of (audio) phase with the other. I'm not an expert on this, but I'm 90% certain that an expert would advise that 2 subs in parallel proximity be wired (or switched) to opposite phase. Two will not fit under one seat. In fact, in my honda accord, only the front passenger seat will accommodate the sub.
[ David  Feb 25, 2020 ]
Yes run in series
[ Jason  Feb 25, 2020 ]
Bought this product for my son at Christmas for his Hyundai Veloster, but he thinks it won't be "loud" enough. His trunk (hatchback) is almost always full due to sports equipment so I thought this narrow style would be perfect and out of the way. If it doesn't produce the sound he'd like, can we add to it?
[ Tricia  Jan 09, 2020 ]
5 answers
For a 60 year old audiofile it filled a gap in my truck just fine. It is a nice piece. Not sure it will fill your sons needs. It is a powered sub so you can't add to it
[ Timothy  Jan 10, 2020 ]
It hits really hard for its size. I mounted mine directly to the bottom of my driver seat in a 2002 Lancer and I love the sound and the feel. I would recommend mounting it that way if you can. The vibrations from the box transfer through the seat and you can feel each bass note that way. I'm going to be buying another one for my other car to replace a two 12" mtx sub box I have in trunk. I think it makes the bass sound cleaner and I definitely feel the bass more with the under seat setup.
[ Brian  Jan 09, 2020 ]
This subwoofer is small but powerful really would work best in the interior space like under a seat
[ Thomas  Jan 09, 2020 ]
Not enough punch for me. Classic rock and heavy metal is how I roll......... I'm used to two 10 inch subwoofers and 75 watt MTX amp in my Honda trunk. This compact dosn't suck but I need more. Limited space in my new truck is the only reason I have this.
[ CRAIG C  Jan 09, 2020 ]
It might depend on how you're providing the audio signal. If you're using the Coax (low level) input then you should be able to another sub (all the appropriate power cabling) and run the 2 together.
[ MICHAEL  Jan 09, 2020 ]
How does a powered sub wire into the factory stereo?
[ Brian  Sep 21, 2019 ]
1 answer
Many of our powered subs offer both line level and speaker level inputs - such as the MTX TN8MS. You can either tap into the speaker wire to get signal or use a line output converter to convert the factory speaker level output to line level. If you have questions about which option is best for you, you can connect with one of our friendly product advisors here:
[ Cosmo  Oct 02, 2019 ]  Staff

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