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Subwoofer box for a Can-Am Defender, Maverick X3 or Commander

Updated October 14, 2026 · 4 min read · ENPTESRU

A side-by-side is not a car: the cab is open, the box gets wet and dusty, and the space under the seats is small. A sub box for a Can-Am Defender, Maverick X3, Commander or Maverick Sport is designed around those three facts.

Where the sub goes

• Under a seat. The most common spot, and the tidiest. On the Defender the bench seats flip up over storage space; on bucket-seat models like the Maverick X3 the space under the seat is smaller. Usually one 8″ or 10″ shallow-mount sub fits.
• Behind the seats or in the cargo bed. Much more room — enough for a 12″ or a ported box — but the box is exposed to weather and takes cargo space. Bolt it down; straps alone loosen on rough trails.
• Prefabricated enclosures. Aftermarket audio brands make under-seat and console enclosures for specific Can-Am models. If one fits your model and year, it is the fastest route; if not, a custom box can use the space better.

Model years, cab options and seat types differ, so the space must be measured on your machine. Make a cardboard mock-up and check that the seat still latches and that nothing rubs on the box over bumps.

Example: a box under the seat

Say the space under the seat is 24″ wide, 12″ deep and 8″ high. With ¾″ walls, the inside is 22.5 × 10.5 × 6.5″ — about 0.89 ft³ gross, or roughly 0.85 ft³ net after the sub itself. That is enough for many shallow-mount 10″ subs in a sealed box, but the inside height of 6.5″ limits the mounting depth: check the sub’s spec sheet. If the space is wedge-shaped, the calculator fits an angled box to it.

No cabin gain: what changes

In a closed car the cabin itself boosts the deep bass by 10 dB or more. An open UTV gets almost none of that, so the same sub sounds noticeably thinner below 50 Hz. To compensate:

• Use as much box volume and cone area as the space allows — two 8″ subs can beat one 10″ in a long, low space.
• If there is room for a port, a ported box tuned around 35–40 Hz gives more output where an open cab needs it.
• With a full cab enclosure (roof, doors, windshield and rear panel), a Defender behaves more like a truck cab and gains some low bass back.

In the calculator, choose “Top down or windows open” for cabin sealing to model an open UTV.

Water, dust and vibration

• Material. Marine plywood, HDPE (marine board) or fiberglass. MDF swells when wet; if you use it, seal it with resin or bedliner.
• Sub and grille. A marine-rated or coated-cone sub survives mud and spray much longer, and a grille protects the cone from boots and cargo.
• Sealed is easier to protect. A port is an open path for water and dust into the box.
• Hardware. Glue and screw every joint, use T-nuts or threaded inserts for the sub, threadlocker on bolts, and mount the box to the frame or seat base, not to thin plastic panels.

Power

A UTV charging system has less spare capacity than a car alternator, especially at idle. Size the amplifier to it, run fused power wire from the battery, and for a large system consider a second battery with an isolator. A sub box that plays loud on the trail but leaves a dead battery at camp is not a good build.

Design it for your Can-Am

Enter the measured space, pick a shallow-mount sub from the database or enter its parameters, choose sealed or ported and an open cabin, and the calculator shows the response, draws the box and gives you the cut list. For a ported box, the port calculator gives the port length on its own.

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