Skip Navigation

MTX ThunderForm Unloaded Enclosure

Holds a single 10" sub — fits 2006-up Honda Ridgeline

4 Reviews

Find what fits your vehicle


Can't find your exact vehicle?

Item # 236HRB10U

This item is no longer available.

Shop all Custom Empty Subwoofer Boxes


Our take on the MTX ThunderForm Unloaded Enclosure

Crinkled french fries, discarded receipts, old gum wrappers — you probably have everything in the hidden corners of your vehicle except great bass. ThunderForm enclosures fill the nooks and crannies of your vehicle with low tones that stand out, but their factory look blends right in.

Crinkled french fries, discarded receipts, old gum wrappers — you probably have everything in the hidden corners of your vehicle except great bass. ThunderForm enclosures fill the nooks and crannies of your vehicle with low tones that stand out, but their factory look blends right in.

MTX engineers evaluate the "sonic signatures" of top-selling vehicles so they can design ThunderForms as custom acoustic matches. Each ThunderForm fits and blends inconspicuously into your vehicle, so you get great bass without losing any space. They're made of high-density polyethylene resin to curb resonances — they deliver bass that's tight, hard-hitting, and way down low. The airtight enclosure provides the correct internal volume to yield optimum bass response.

This black enclosure comes without a speaker — you install your favorite 10" subwoofer. For best results, MTX strongly recommends using a speaker designed for an enclosure with a volume of 0.92 cubic feet. The enclosure mounts under the rear passenger seat of select 2006-up Honda Ridgeline pickups.

Please check with us before purchasing by using the vehicle selector on our site, or calling an Advisor at 1-888-955-6000 to verify fit information.

Product Highlights:

  • custom-fit black subwoofer enclosure for 10" sub
  • mounts under rear passenger seat
  • fiberglass construction
  • volume: 0.92 cubic feet (sealed)
  • dimensions: 18-1/8"L x 9-1/4"H x 12-5/8"D
  • mounting depth: 6-1/5"
  • warranty: 2 years
  • Our 60-day money-back guarantee

What's in the Box:

  • Custom-fit unloaded 10" subwoofer enclosure
  • Installation instructions

MTX ThunderForm Unloaded Enclosure Reviews

Average Customer Review(s):

(4 Reviews)

Perfect fit !

Broadbandit from Forest Hill, MD on 6/12/2016

2014 Honda Ridgeline
Crutchfield Customer Review (What's this?)

I purchased this sub enclosure so it would fit under my rear passenger seat. I was concerned at price but after a lot of shopping I could not find a proper sub box that would fit under that seat. I like the idea this box looks like part of the factory truck. I was also worried after ready many reviews that my subwoofer speaker I purchased before the the sub box may not fit. Well my subwoofer is a dual coil very large 10" sub and it fits in the custom sub box like a glove. Very happy with box, price and fit. Great product. !

Pros: Looks great Custom fit Matches factory interior

Cons: Price but worth it.

Great fit

Phil from the Washington, DC Area on 2/8/2015

Crutchfield Customer Review (What's this?)

This box fits great under the rear seat. At first I didn't think it would and was upset. But once i set it in there and put the seat down, I was happy again. The amp fits right under the front seat so I did not lose anymore room in the back which I was afraid of happening. I purchased an Alpine Type S sub that fit perfect with no issues.

Pros: Perfect fit, great sound, great quality

Cons: Price, would be nice to have color options to match rest of interior but that's just being picky.

Excellent enclosure - but choose the right subwoofer

Tom G from Reno, NV on 5/29/2013

Crutchfield Customer Review (What's this?)

The MTX Thunderform fits perfectly under the rear passenger side seat of the Ridgeline. It is very well made, but it is 0.92 cubic feet and has a fairly low tolerance for sub cutout diameter and depth. I was hoping to install my Image Dynamics IDQ10 subwoofer into it, but the enclosures cutout is too small - needs about another quarter inch in diameter to accomodate the IDQ10. The big JL Audio subs (W6 and W7) won't fit in this enclosure because of their depth. Luckily, I found the perfect subwoofer to fit into this enclosure - and it's an outstanding sound quality (not sound pressure level) subwoofer. The Morel Ultimo SC 10" sub works well with enclosures as small as 0.55 cubic feet up through 1.1 cubic feet. After allowing the subwoofer to break in for about 20 hours or so, I am completely satisfied with the sound performance of the combination of the MTX Thunderform and the sub.

Pros: Fits perfectly under the rear passenger seat of the Ridgeline. Solid build quality. Perfect when combined with my subwoofer.

Cons: Due to the Ridgeline's space constraints, only a few high end subwoofers will actually fit.

Best for ridgeline

Brandon from Athens, GA on 12/8/2010

2006 Honda Ridgeline
Crutchfield Customer Review (What's this?)

It works, I love it, and I'm not having any problems (anymore). The mounting depth (which I had to find on the manufacturer's website) is wrong. There is a bar along the inside where the sub is supposed to be. The depth becomes a little under 6" I believe. I got an Alpine Type-R 10" for the enclosure and was very disappointed when it didn't fit. Luckily a 3/4" MDF spacer ring fixed my issue and still allowed the sub to hit. The sound is a bit more muffled being so close to the floor, but the sound is still awesome. I have an Infinity 600w rms running to the sub and it gets the job done. If you want something for the Ridgeline that sounds good, get this. If you want something that will give you a headache, skip this and get a custom box that fits three 8" subs. All in all I found this worth the price with no regrets.




Hands-on research

Product Research


Vehicle-Specific Custom Enclosure: The enclosure mounts under the rear passenger seat of 2006-2010 Honda Ridgelines.

Note: Please refer to the Crutchfield Vehicle Selector to confirm fit for your vehicle.

Construction: The sealed enclosure features fiberglass construction.

Tools For Installation:

  • Powered screwdriver

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 verify what’s in the box, 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.