WOOFER SPECIFIC OR UNIVERSAL

Subwoofer Box

Sealed, ported, wedge and down-fire boxes from 6.5 to 15 inch. CNC cut in Tullahoma. Made in the USA.

Car subwoofer enclosure with American flag design on a gray background

WOOFER SPECIFIC OR UNIVERSAL

A subwoofer box is not an accessory to the driver, it is half the driver's output. The same 12 inch sub in two different boxes measures differently, plays a different low end, and takes a different amount of power to get there. Which is why Audio Intensity cuts enclosures on its own CNC rather than reselling a universal box that has to fit everything.

Start with the size you are running. Then decide how much of your subwoofer's capability you actually want back.

6.5 to 15 inch · sealed, ported, wedge, down fire · $94 to $1,899.99 · cut in Tullahoma

Made in the USA. Cut from American MDF on American machines in Tullahoma, Tennessee, then assembled and finished to your order and shipped in 2 to 3 business days. Full manufacturer warranty. Expert SQ-judge support.

Designed and cut by Scott Welch, founder of Audio Intensity, IASCA National and MECA World Champion and an IASCA Finals judge since 2019.

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What a Universal Box Costs You

A universal 12 inch box is designed to be acceptable with every 12 inch subwoofer ever made. That is a real engineering constraint and it has a real cost: the internal volume has to sit in the middle of the range, the port has to be tuned to a frequency that offends nobody, and the bracing has to assume a driver that may or may not need it.

Your subwoofer has a published set of Thiele-Small parameters. Its Vas tells you what air volume it wants to see. Its Fs and Qts tell you what alignment suits it and where the rolloff lands. A box cut to those numbers is not a marketing claim, it is arithmetic, and the difference between a matched box and a nominal one shows up as low-end extension, power handling and cone control.

Accurate volume is the easy part. What separates a Proline X enclosure from an imported box is that every seam has mechanical purchase instead of relying on glue and staples across a butt joint. Performance, Performance Optimized and Professional use dado and V-groove joints cut on the same pass as the panels. Micro and Vehicle Specific are stack-fab, MDF layers bonded under pressure with dowel reinforcement. A butt-jointed box works loose. A box built either way does not.

Audio Intensity can tell you where the wood comes from. Every enclosure is cut from Langboard Elite MDF, pressed from 100% Southern Yellow Pine in Willacoochee, Georgia, on ShopSabre routers engineered and built in Lakeville, Minnesota, in a shop in Tullahoma, Tennessee. Qpower and Atrend import their enclosures from China. Ask either of them what board is in the box and see what answer comes back.

How to Choose a Subwoofer Box

Four questions decide it, and only the first is about size.

What size subwoofer are you running?

Audio Intensity cuts enclosures for 6.5, 8, 10, 12, 13 and 15 inch drivers, in single, dual, triple and quad configurations. Size is the first filter because it is non-negotiable: a 12 inch driver does not go in a 10 inch box. Everything after this is a genuine choice.

Sealed or ported?

Sealed boxes are smaller, roll off gently below tuning, and give the tightest transient response, which is why sound quality builds usually run sealed. Ported boxes are larger and louder at and above the tuning frequency, trading some control for output. If you compete on SQ, or your music has real low-end detail, sealed. If you want maximum output for the power, ported.

Do you know which subwoofer is going in it?

This is the question that changes what you should buy. If you already own the driver, a Performance Optimized or Micro Series enclosure cut to that specific subwoofer will outperform a universal box of the same external size. If you have not chosen a driver yet, or you swap subs often, a P-series universal box is the right answer and costs less.

How much space can you actually give up?

Measure before you order. Down-fire and wedge enclosures fit under seats and against rear walls where a standard box will not go. Vehicle-specific enclosures for the F-150, F-250, Bronco and Tacoma use factory dead space and cost no usable cargo room at all.

Measuring Before You Order

Three numbers decide whether a box fits, and only one of them is the box's external dimensions.

Measure the opening first. A trunk pass-through, a rear seat gap or a truck cab opening will stop a box that would otherwise sit fine once inside. Measure the mounting depth of the subwoofer itself, from the mounting surface to the back of the magnet, and confirm it clears the rear panel of the enclosure. Then measure the space with the seat in its rearmost position and the cargo cover fitted, not with everything removed.

For behind-seat truck enclosures the constraint is usually seat travel rather than the box. The Audio Intensity F-150 behind-seat enclosures are cut to the cab profile of a specific model year range, so a 2015 to 2023 box will not fit a 2024 truck.

If you are unsure, send the vehicle and the subwoofer through the contact page before ordering. Fitment questions are faster to answer than returns are to process.

Four Ways to Buy a Subwoofer Box

Audio Intensity cuts four kinds of enclosure, and the right one depends less on your budget than on how much you already know about your build. Find yourself below and the shortlist narrows to a handful.

Universal

You have a sub and want a solid box

Any driver, right size·$94 to $279.99

The P-series covers sealed, ported, wedge and down-fire in every size from 6.5 to 15 inch. Cut from the same MDF and braced the same way as everything else here, sized to suit the broad middle of each driver class. The right answer if you swap subwoofers often or have not chosen one yet.

Driver Matched

You want the most performance from your sub

The bulk of the range·$199.99 to $1,750

Performance Optimized, Micro, Professional and X Series enclosures are cut to a named subwoofer's published parameters rather than to a nominal diameter. Built for Arc Audio, JL Audio, Image Dynamics, ResoNix, Wavtech, Morel, Hertz, Rockford Fosgate, Alpine, Kicker, Prodigy and more.

Loaded

You want it done in one order

Driver fitted·$249.99 to $1,899.99

The enclosure with the subwoofer already installed and wired to a terminal cup. Matched, tested and finished before it ships, so the install is a mounting job and a wire run rather than an afternoon of measuring.

Vehicle Specific

You have no space to give up

Named vehicles·$329.99 to $1,499.99

Cut to the factory dead space in a specific model year range. F-150 and F-250 behind-seat, Bronco and Tacoma. These cost no usable cargo room, which is why they exist.

Fitment is model-year specific. A 2015 to 2023 box will not fit a 2024 truck.

Every enclosure is cut before it is listed, so the count shown on each product is a real rack count rather than a build estimate.

Frequently Asked Subwoofer Box Questions

What is a sub box?

A sub box is the sealed or ported enclosure a car audio subwoofer mounts into. It is not a housing, it is an acoustic component: the internal volume, the port tuning and the panel stiffness together determine how low the system plays, how loud it gets and how much power the driver can take. The same subwoofer in two different boxes measures differently.

Is it cheaper to build a sub box?

In raw material, yes. A sheet of MDF and a router bit costs less than a finished enclosure. In practice the gap closes fast: you need accurate volume calculation for your specific driver, a way to cut square panels repeatably, mechanical joinery rather than butt joints, bracing, sealing, and a finish that survives a car. Audio Intensity cuts on a CNC to the driver's published parameters, which is the part that is hard to reproduce with a circular saw.

How much does a sub box cost?

Audio Intensity enclosures run from $94 for a single 8 inch sealed box to $1,799.99 for a loaded dual 12 inch system with the subwoofers installed. A universal P-series box in the most common sizes sits between $129.99 and $269.99. Enclosures cut to a specific driver start around $199.99.

Is a sealed or ported sub box better?

Neither, they do different jobs. Sealed boxes are smaller, roll off gently, and give the tightest transient response, which is why sound quality builds run sealed. Ported boxes are larger and produce more output at and above the tuning frequency, trading some control for volume. Choose sealed for accuracy and ported for output.

What subwoofer box hits the hardest?

A ported enclosure tuned near the driver's resonance will produce the highest output for a given amount of power, which is what most people mean by hitting hard. That output comes with a steeper rolloff below tuning and less control on transients. A larger ported box tuned lower will play deeper but feel less aggressive in the midbass.

Do I need a box cut for my specific subwoofer?

Not always. If you swap subwoofers often, or have not chosen one yet, a universal P-series box is the right answer. If you already own the driver and want everything it is capable of, an enclosure cut to its published parameters will outperform a nominal box of the same external size on extension, power handling and cone control.

Last updated August 23, 2026