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MTX ThunderForm Unloaded Enclosure

Holds a single 10" sub — fits 2007-up Chevy Silverado 1500 and 2500 Extended Cab (Black)

2 Reviews

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Item #: 23615EX10U

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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 1.0 cubic foot. The enclosure mounts under the rear seat of select 2007-up Chevy Silverado 1500 and 2500 Extended Cab 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.

What's in the Box:

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

Product Highlights:

  • custom-fit black subwoofer enclosure for 10" sub
  • mounts under rear seat on the driver's side
  • fiberglass construction
  • volume: 1 cubic foot (sealed)
  • dimensions: 36-1/5"L x 8"H x 16-2/5"D
  • mounting depth: 5-5/8"
  • warranty: 2 years
  • Our 60-day money-back guarantee

MTX ThunderForm Unloaded Enclosure Reviews

Average Customer Review:

2 Reviews

Worth it

Eric from Bismarck, ND on 4/18/2016

2010 Chevrolet Silverado
Crutchfield Customer Review (What's this?)

I have to admit I was a little hesitant to spend this much money on a sub box, but you know how much space is limited in a truck so I decided to do it (I have no room behind seat for a slim regular box). After install, I have to say it fits like a glove under the bench seat and looks OEM. Sounds great too (paired with a 10" Kicker Comp S). Plus since it's fiberglass, doesn't add any weight, so that's nice. Also, nice solid spring-loaded speaker wire connectors. My only complaints are: 1) I don't know why all these vehicle-custom box manufacturers insist on making these for under the driver's side's a truck! Now I need to go around to the passenger side to get the tools and straps under my backseat. Maybe there is a sound reason for it, but I think I would take a small decrease in perfect sound wave reflection for the sake of vehicle usability. But I looked at three different manufacturers, and they all put it under the driver's side. 2) The mounting brackets they sent aren't tall enough to use the mount point on the box (had to bend the brackets to make it work, but hey, in the end it worked fine). 3) Not really a complaint, but on this specific box with my truck, make sure to get your speaker wire connected first before mounting the box. The connection is in a strange place, and you can't get to it again without un-mounting the box again. But, all in all, great product. Would definitely recommend. So far, really liking it.



More reviews would help...

Tater from Virginia Beach on 6/28/2011

Perfectly fits under the rear seat behind the driver in my 2011 silverado 1500 extended cab, didn't even need to use the screws to keep it to the floor, just some double-sided sticky tape along the bottom to adhere to the carpet. I had some trouble picking the right sub enclosure because of a lack of reviews, and for the price, this single-enclosed box for a 10" sub (I used a Sony Xplode woofer) gives some tight, clean bass inside the cab. Perfect for rolling through your neighborhood at 2am on the way home after a long shift, because the acoustics stay INSIDE the cab of your truck. After talking with a crutchfield rep about the specs, he even sent me a more detailed picture of the box (installation guide) before I made the purchase. We shall call him "Bill" for the moment, since unfortunately I cannot remember his name. Thank you VERY much Bill, I would not have the sound system that I wanted if you had not helped me. I would have bought something much more expensive that would have been twice as difficult to install and configure, you saved me time and mucho dinero. If you've got a silverado, don't spend $500 on a sub box that doesn't fit. This one is worth it.




Hands-on research

Product Research


Vehicle-Specific Custom Enclosure: The enclosure mounts under rear seat in select 2007 and later Chevrolet/GMC Extended Cab trucks.

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
  • #2 Phillips head bit
  • 6" Bit holder extension
  • 10mm socket
  • Socket Wrench

Our Product Research Team

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