Subwoofer box for a Ford F-150 or F-250
The F-150 is the best-selling truck in the US, and its cab dictates the box: in a SuperCrew the sub hides under the rear seat, in a regular cab it squeezes in behind the seat. The truck cab is small, so a modest box sounds bigger than it would at home.
Where the sub goes, by cab
- SuperCrew (four full doors). The rear seat cushion flips up. Underneath there is room for a long, low box — usually two shallow 10″ subs, or one 12″. On some years and trims the space has a fold-out load floor or storage bins: measure what is actually there.
- SuperCab (small rear doors). Same idea, but the space under the rear seat is shorter and lower. One shallow 10″ or two 8″ is typical.
- Regular cab. Behind the seat there are only a few inches. It takes a thin box with shallow subs, angled to follow the seat back.
- F-250 / F-350 Super Duty. The same layouts: under the rear seat in a crew cab, behind the seat in a regular cab. Brackets and storage differ, so measure your own truck.
Some trims come with a premium audio system that already has a subwoofer. Check before you plan the space — an aftermarket box usually replaces it.
Pick a sub for this spaceThe calculator opens with the vehicle and the space from this guide and lists the subs that fit there, each with its box. Then adjust the size to your own vehicle.
Example: two 10″ under a SuperCrew seat
Say the space under the rear seat is 50″ wide, 12″ front to back and 9″ high. With ¾″ walls the inside is 48.5 × 10.5 × 7.5″ — about 2.2 ft³ gross. Two shallow 10″ subs need about 0.6–0.8 ft³ each sealed, so they fit with room for the subs themselves. A single 12″ ported box would need 1.5–2.5 ft³ net plus a port — possible only at the small end and with a shallow sub. The 7.5″ inside height is the real limit: check the sub’s mounting depth before you buy it.
Cab gain: why small boxes work
A truck cab is a small, fairly sealed space. Below roughly 60–70 Hz it raises the bass by several dB per octave, so a sealed box that sounds lean in a room sounds deep in a cab. The buttons in “Pick a sub for this space” above open the calculator with this already set: the vehicle, where the box goes and the size of the space.
Build tips for trucks
- Down-firing subs under a seat need at least the sub’s recommended clearance to the floor; a raised baffle or feet fix that.
- Bolt the box to the seat brackets or the floor. A loose box is dangerous in a crash.
- Run the power wire through an existing firewall grommet and fuse it close to the battery.
Design it for your truck
Enter the measured space, set the box as an angled wedge if the seat back leans in, pick your sub from the database and compare sealed and ported. The calculator draws the box, checks that the subs and the port fit, and gives you the cut list and DXF. More on fitting boxes into cabs: under-seat and truck boxes.
Model it for your own subResponse in your car, cone excursion and port air speed — free, no signup.Open the calculator →FAQ
Where does a subwoofer go in an F-150?
In a SuperCrew, under the rear seat: the cushion flips up and a long, low box with one or two shallow subs fits underneath. In a SuperCab the space is shorter and lower. In a regular cab there is only a few inches behind the seat, so it takes a thin box with shallow subs.
What size sub fits under the rear seat of an F-150 SuperCrew?
Usually two shallow 10″ subs in a sealed box, or one 12″ in a shallow box. Measure the width between the seat brackets, the height to the folded cushion and the depth to the floor hump — those three decide it.
Sealed or ported in a truck cab?
A truck cab is small, so it lifts the deep bass a lot: a sealed box sounds deep in a cab and takes less room. A ported box needs more volume and a port, which is hard to fit under a seat.
Does an F-250 take the same box as an F-150?
The layout is the same idea — under the rear seat in a crew cab, behind the seat in a regular cab — but the brackets, floor and storage differ by year and trim. Measure the truck you have instead of copying a box from another one.