If you're hunting for a 2013 f250 sub box, you've probably already realized that Ford didn't exactly leave us a ton of extra room to work with behind those rear seats. It's one of those weird ironies of owning a Super Duty—the truck is absolutely massive on the outside, but the moment you want to add a little bit of bass, the interior feels like a compact car. I've spent way too many hours measuring the gap behind the bench seat of a Crew Cab, and let me tell you, every fraction of an inch matters.
The stock sound system in the 2013 models is okay. It gets the job done for talk radio or catching the news, but if you actually like feeling your music, it's pretty lacking. Adding a dedicated subwoofer is the single best upgrade you can do, but the struggle is finding a box that fits without making your passengers sit with their knees tucked into their chests.
The Struggle of Space in a Super Duty
The biggest hurdle with a 2013 f250 sub box is the depth—or lack thereof. If you have a Crew Cab, you're looking at a very narrow wedge-shaped space behind the rear seat back. If you have a SuperCab, things are even tighter. Most people want to keep their under-seat storage because, let's be real, that's where the tow straps, tools, and random junk live. That leaves the back wall as the only viable spot.
When you start looking at boxes, you'll notice they are almost all "shallow mount" designs. You aren't going to fit a massive, full-sized 12-inch competition sub back there unless you're prepared to do some serious fabrication or move the entire seat forward. Most of us just want a clean install that looks factory and doesn't rattle the teeth out of our passengers.
Behind the Seat vs. Under the Seat
This is the age-old debate for F250 owners. If you go with a box that sits under the rear seat, you usually get more air volume. More air volume means you can use a wider variety of subwoofers and potentially get deeper bass. However, you lose your floor space. If you fold your seats up to put a dog back there or haul groceries, an under-seat box is constantly in the way.
That's why the behind-the-seat 2013 f250 sub box is so popular. It's tucked away, completely hidden from prying eyes, and doesn't sacrifice any utility. The downside? You are limited to shallow subs, and the box volume is usually pretty small, which means the bass will be punchy but maybe not "shake the neighbor's windows" loud. For most of us, that's a fair trade-off.
Choosing the Right Subwoofer for the Box
You can't just buy any 10 or 12-inch speaker and expect it to work. You need to look specifically for shallow-mount subwoofers. These are engineered to work in tiny enclosures. Brands like JL Audio, Rockford Fosgate, and Kicker make some great ones that are specifically designed for truck applications.
When you're picking a sub to go into your 2013 f250 sub box, pay close attention to the mounting depth. If your box has a mounting depth of 4 inches and your sub is 4.25 inches, you're going to be a very frustrated person on install day. Also, check the recommended air volume. A box that's too small will make the sub sound "choked" and tight, while a box that's too big (rare in this truck) can lead to the sub over-extending and blowing out.
Single vs. Dual Sub Setups
Do you want one 10-inch sub or two? In a 2013 F250, a single 10 or 12 is usually plenty to fill the cabin. Because the cab is relatively small compared to a massive SUV, the "cabin gain" helps boost those low frequencies. However, if you really want that heavy hit, some companies make dual 10-inch boxes that span the entire width of the back wall. Just keep in mind that with two subs, you're cutting into the space where your jack or power window motor might be located.
Installation Tips and Tricks
Installing a 2013 f250 sub box isn't exactly rocket science, but there are a few things that can trip you up. First off, you'll probably need to remove the carpet padding on the back wall of the cab. That extra half-inch of foam takes up valuable real estate. Scrape it off or cut it out where the box sits to get the enclosure as flush against the metal as possible.
Another common trick is the "seat spacer" move. If you find that the seat back is pressing too hard against the sub (which can damage the surround or the cone), you can buy or make small spacers to lift the seat brackets up and forward about half an inch. It doesn't sound like much, but it makes a world of difference for clearance.
Dealing with the Power Sliding Window
If your 2013 F250 has the power sliding rear window, you've got a motor assembly sitting right in the middle of the back wall. This is a huge pain for sub box design. Most pre-made boxes are notched out to fit around this motor. If you're building your own box or buying a generic one, make sure it accounts for that motor, otherwise, you'll be returning it before the sun goes down.
Material Matters: MDF vs. Fiberglass
Most of the 2013 f250 sub box options you'll find online are made of MDF (Medium Density Fiberboard). It's cheap, it's sturdy, and it sounds good. Just make sure it's well-sealed and preferably coated in bedliner or carpeted. Since it's going in a truck, it might get exposed to some moisture or temperature swings, so a durable finish is a plus.
If you're going for a high-end custom build, some guys use fiberglass. Fiberglass allows you to contour the box perfectly to the weird humps and bumps of the truck's floor and back wall, squeezing out every last cubic inch of air volume. It's way more expensive and time-consuming, but if you're a true audiophile, it's the way to go.
Why a Custom Fit Beats a Universal Box
I've seen people try to wedge a universal "truck box" from a big-box store into a 2013 F250, and it almost never looks right. They usually stick out too far, preventing the seat from latching, or they slide around every time you hit the brakes. A vehicle-specific 2013 f250 sub box is designed to use the factory bolts or fit snugly into the existing recesses. It stays put, it looks clean, and it actually lets you use your truck like a truck.
Plus, a lot of these vehicle-specific boxes come pre-loaded with a subwoofer and a matching amplifier. If you don't want to spend your whole weekend matching ohms and calculating wattage, a pre-loaded "loaded enclosure" is a lifesaver. You just run your power and signal wires, and you're basically done.
Final Thoughts on Upgrading Your Bass
At the end of the day, adding a 2013 f250 sub box is about making your time behind the wheel more enjoyable. Whether you're hauling a trailer across the state or just commuting to a job site, having a sound system that actually has some "thump" makes the drive go by a lot faster.
Just remember to measure twice, check your seat clearances, and don't be afraid to pull back that rear carpet to make things fit. It's a bit of a project, but once you hear that first bass drop without the speakers distorting, you'll know it was worth every bit of effort. These trucks were built to work hard, but there's no reason they can't sound good while doing it.