Q-Logic enclosures take the guesswork out of box-building, so you can enjoy great bass without the time-consuming process of constructing your own enclosure. The QLT-.8512SE accommodates one 12" subwoofer in a sturdy housing made entirely of non-resonant medium-density fiberboard. This box features reliable locking-joint construction, and is impeccably upholstered with durable gray carpet.

Since subwoofers' basket design and bolt patterns vary by brand, Q-Logic's ingenious QxE seal ring allows you to customize the box opening for virtually every woofer available. Plus, a cool-looking, one-piece grille works even with woofers that have large roll surrounds, so you get solid protection and sharp looks.

The box comes with a grille (with screws), a set of spring posts, polyester fiber stuffing, and speaker leads with quick-slides for easy connection to your woofer.

This box is designed to fit behind the seat in your pickup. Some truck boxes may not fit in a standard cab with the seat pushed all the way back, so please measure the planned installation area to ensure fit.

Key Specifications:
  • for one 12" subwoofer
  • 0.85 cubic feet internal volume
  • dimensions:
    • width: 22-1/2"
    • height: 15-3/4"
    • bottom depth: 8-3/8"
    • top depth: 5-3/16"
  • 1-year warranty

Why do I need an enclosure?

An enclosure is simply the box that houses your sub; sealed and ported enclosures are the most popular types. A sealed enclosure is usually smaller in size, sacrificing a little volume level to deliver more accurate bass. The ported enclosure features a vent which allows bass waves to escape from behind the mounted sub, augmenting the bass coming off the front of the sub. Ported boxes are louder, bigger, and a little less accurate. Every sub works best in the size and type of enclosure that's recommended by the manufacturer, so make sure you match your sub with the right box.

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Hands-on research

What's in the box?

Download owner's manual

  • Single truck-style enclosure
  • Plastic grille
  • Two 1-1/2" self-tapping screws (installed in grille)
  • QxE-Ring (installed)
  • 2' length of speaker wire (with 0.205" female quick slides on both ends)
  • Eight 1" self-tapping screws
  • Polyfill batting (22" x 13")
  • Instruction/Warranty sheet

Product Research


Materials: The box is constructed of 5/8" MDF (medium-density fiberboard), with a second MDF panel adhered to the back of the front panel to provide the mounting surface for the woofer. MDF resists flexing and has anti-resonant qualities.

Design: For strength, Q-Logic uses a full dado groove on the front, back, top, and bottom panels. The side panels are glued, then locked into these grooves. The edges of the front, back, top and bottom use mitered joints, so there's 50% more surface area for the special glue that bonds them. The side panels of the box are recessed 0.5". The enclosure is covered with durable gray carpet.

QxE-Ring: The QxE-Ring is a multi-diameter woofer mounting adapter which also seals the woofer into the enclosure. The QxE-Ring has a series of rings around the outside to help center the woofer, and hash marks to help align the woofer's mounting holes. If the mounting diameter of the woofer is 11-1/8" or less, the woofer can be installed without trimming. For woofers with a larger mounting diameter, a portion of the QxE-Ring can be trimmed off, allowing for an extra 1/4" in woofer mounting diameter.

Plastic Grille: The one-piece plastic grille fits into outer edges of the enclosure opening and is held in place with two self-tapping screws. The grille offers nearly an inch of "headroom" to accommodate woofers with large roll surrounds. Note: The grille adds approximately 3/4" to the overall depth of the enclosure when mounted.

External "Top Hat": Mounted to the rear of the enclosure, the External Top Hat is an oval-shaped plastic insert which extends the woofer mounting depth by nearly 3/4", allowing more woofers to fit into the enclosure. The cutout for the insert is 7-1/2" wide and 6" high. The external panel is 9-1/4" x 7-5/8" (oval), but protrudes less than 1/4" from the back panel.

Spring Posts: The spring posts, located on the rear of the enclosure, will accept bare wire, pin connectors, banana plugs, and dual banana plugs.

Brackets: Brackets (not included) are recommended for more secure mounting.

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.