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MTX TN8MS 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...

Find what Fits your vehicle


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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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24 questions - 37 answers

Item # 236TN8MS

In stock

About the MTX TN8MS

Bob Bihlmayer

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
  • 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
  • Four M3x6mm Machine screws
  • Owner's manual (English/ Spanish/ Portuguese/ French)

Customer reviews for MTX TN8MS

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4.5 out of 5 stars
126 reviews

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More details on the MTX TN8MS

Pat M.

Features & specs

Enclosure Type Sealed
Finish Material Aluminum
Grille Steel
Connector Type RCA, Harness
Quick-disconnect Plug No
Bi-amp Inputs No
Woofer Size (inches) 8
Woofer Material
Passive Radiator ---
Width 9-11/16"
Height 3-1/4"
Depth 14"
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

24 questions already asked

I would like to install this in a 2024 GMC 2500 Denali with a factory. What install kit would I need? Can I install it behind the rear seat?
allan  Feb 22, 2024
1 answer
Hey Allan, thanks for the question. So we still have not had the opportunity to research that Denali to the fullest yet, therefore I don't have a definite bit of information to let me know if something stands in the way of that installation such as an active noise cancellation system since those are the bane of a good aftermarket sound system or a factory amp. Assuming nothing stands in the way, you would only need an 8-gauge amp wiring, speaker wire, RCAs, and a good line output converter to help clean up any audio signal we would be getting by tapping into the existing speaker wire. As far as mounting it behind the rear seat, that location should be sufficient for that powered sub. If you want to explore some options, we have advisors who can be reached by calling 1-800-324-9695 that can help recommend the best connectors for your install.
red  Feb 22, 2024 (Staff)
What wiring kit do I need for a 2017 Chevy Colorado?
jc2lite  May 21, 2023
1 answer
Thanks for your question, James. This powered subwoofer calls for an 8-gauge amp wiring kit and a 15 amp fuse. I recommend reaching out to an Advisor either by phone 1-800-324-9695 or online chat, they'll be happy to put a cart together for you.
andrea  May 21, 2023 (Staff)
Can I hook this up to my factory 2014 ford f150 factory stereo? Do I need to purchase more connections to do?
adam  Apr 11, 2023
1 answer
This MTX TN8MS Terminator Series 8" powered sub is perfect for installing into factory systems, Adam. You will need some extra bits for a complete install if you are planning on tackling the job yourself. In addition to the TN8MS, grab these items in the links below. This EFX 8-gauge wiring kit is high quality and comes with the RCA cables included. The Kicker 46KISLOC2 K series 2-channel line out converter will provide a strong line-level signal and a 12-volt turn on lead. The Posi-Products Posi-taps in the link below are an excellent way to "tap-in" for the line output converter without cutting your existing speaker wires. With these three items plus the MTX Terminator sub, you have a recipe for success!
bo  Apr 11, 2023 (Staff)
Will this fit on the front of passenger underseat of toyota sedan?
otabs  Feb 08, 2023
1 answer
We will need more information about your vehicle in order to answer this. It is likely that you'll need to take measurements of the space you have in mind to confirm fit. The measurements of the TN8MS are 13-15/16"W x 3-1/4"H x 9-5/8"D.
zachary  Feb 09, 2023 (Staff)
Can I hook this up to my factory stereo in a 2013 Honda Civic LX?
sam  Dec 11, 2022
1 answer
Yes you can add that powered subwoofer to your stock system. It comes with a speaker wire input harness so you can tap into your existing wiring for convenience.
arielle  Dec 12, 2022 (Staff)
Can this subwoofer be plugged into an after market amplifier? I'm a complete noob with car audio.
matthew  Dec 07, 2022
1 answer
This sub is actually a powered sub meaning it has an amp already built in to power the sub in the enclsoure. This sub features a class A/B amplifier outputting 135 watts RMS. You would not be able to plug this into another amp.
allison  Dec 08, 2022 (Staff)
My Sony head unit has a mono rca sub output. Which sub input do I use on the amp? Left or right?
chris  Sep 25, 2022
1 answer
We recommend using an RCA Y adapter to split that output into 2 and feed audio into both inputs. Our Y adapters can be found here:|Y-adapter
jason  Sep 25, 2022 (Staff)
Do I need to connect the sub to the battery because it has the built-in amp, or will it connect straight to the radio? Then if it goes into the radio, If I use 2 of these, will I need separate sub connections to the radio or can I combine them somehow?
michael  Sep 20, 2022
1 answer
If you use 2 subwoofers then you will need to run power to the battery but you can run a single cable with a distribution and split that to the two subwoofers. You will have to connect them to the radio for signal but you can use a splitter to the inputs for the subwoofers so they work in tandem with each other. If you give us a call at 800.324.9695 one of our advisors can get everything together that you would need to get that set up going for you!
arielle  Sep 20, 2022 (Staff)
Do I need to connect the sub to the battery because it has the built-in amp, or will it connect straight to the radio?
michael  Sep 20, 2022
1 answer
You will need to run power to the battery because it has the built in amp. You will also connect the subwoofer to the radio but that will only be for signal.
arielle  Sep 20, 2022 (Staff)
Will this fit under the front passenger seat of a 2019 Honda HRV?
lloyd n.  Jul 25, 2022
1 answer
Greetings Lloyd, and thank you for your question. While the MTX TN8MS is designed to fit under most vehicles seats, it will not 100% of the time. Unfortunately we do not take under seat measurements on vehicles. I would take the MTX dimensions 13-15/16"W x 3-1/4"H x 9-5/8"D, then measure under your seat to see if it can fit.
hogan  Jul 25, 2022 (Staff)
Does it come with all the wiring needed, or do you have to buy that separately?
jammi m  Jul 04, 2022
1 answer
The MTX TN8MS requires 8-gauge wiring kit with 15-amp fuse which is sold separately. If you are connecting this to a stock radio it does come with a 10" speaker level input harness. If you are connecting this to an aftermarket radio you will need an RCA cable. This 8 gauge kit comes with an rca cable and this kit comes without the rca cable if using speaker level inputs
allison  Jul 05, 2022 (Staff)
Does it come with all the wiring needed, or do you have to buy that separately?
jammi m  Jul 04, 2022
1 answer
That's a good question Jammi. This MTX TN8MS will need some additional wiring to be installed. The first thing you will need is a power and ground wiring kit, the Crutchfield CK8 in the link below is a perfect match AND you get a little discount when paired together. If you are connecting to an aftermarket radio with RCA outputs, you'll also need this RCA cable in the second link below. If you are dropping this sweet MTX TN8MS into a factory radio'd vehicle, you'll need some extra speaker wire in the third link for the speaker inputs. You can always give is a call at 1-800-324-9695 and an Advisor can make sure you get all the gear you need too, we are here anytime!
bo  Jul 05, 2022 (Staff)
Will this sub fit under the front seat of a 2020 Mini Cooper Countryman and can it be connected to the Harmon Kardon system?
maurice radar  Jun 03, 2022
1 answer
Thank you for the questions Maurice. There is a way to connect a powered sub into any vehicle. In some cases you may need a line output converter, or one that has bass restoration as well. Newer cars factory radios have bass roll off. As you increase the volume you get less bass. I would be using the Audio Control LC2i line output converter. As far as will it fit under your Countryman seats, we do not take measurements under seats. The MTX TN8MS is 3.25 inches tall. If you measure under your seat and have that, of course it will fit.
hogan  Jun 03, 2022 (Staff)
Does this come with any mounting hardware, to be able to bolt it down?
brandon515  May 22, 2022
1 answer
Yes, small brackets come with it. But the sub I had vibrated off the brackets. I ended up going to Home Depot and buying ratchet straps to tie it down.
paul a  May 22, 2022
Do I need a separate amplifier for this Sub?
andre  Apr 29, 2022
6 answers
No. Sub has it's own amp.
donna  May 03, 2022
Hi, no you don't. It has power amp built in. It's great for adding that lower bottom end missing from most vehicles. Buy two if you really want that "THUMP"
m  Apr 29, 2022
No it's a powered sub amplifies bass quite well with adjustable control
roger l  Apr 29, 2022
Nope! Amp is included within this package, not separate amp is required for purchase.
benjamin  Apr 29, 2022
would not need an external amplifier it's already built into the enclosure Enter an answer to this question.
david  Apr 29, 2022
It has a built in amp
brian  Apr 29, 2022
Will it fit in a 95 Tacoma ext cab?
wyatt  Jul 29, 2021
3 answers
I am sorry, I don't know. I installed mine in a 2006 mazda3 hatchback. It just fit under the front seat.
m  Aug 02, 2021
I would think so. I put mine behind the passenger set in my bmw roadster
john  Aug 02, 2021
It's pretty thin. I Fit it in a gen 3 behind back seat, but maybe it could go under the seat if not
vance  Aug 01, 2021
I have a 2019 Ford Flex with the Sony package. Would this be an upgraded solution to replace the weak sound of the factory sub? I canâ??t comprise any space since we are a baseball family.
stephen  Sep 29, 2020
2 answers
Definitely an upgrade over any factory sub, it fits perfectly under the driver seat of my 2019 Honda CRV
thomas  Oct 01, 2020
If all your looking for is more bass to round out your sound its great. If your looking to have serious bass you might be disappointed.
patricia  Sep 30, 2020
Just installed it in my truck and it worked really good, intil he went cruzin and came back with it blown, whats the warranty on this item?
john  Sep 27, 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.
thomas  Oct 19, 2020 (Staff)
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.
thomas  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 r  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  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:
casey  Oct 02, 2019 (Staff)

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