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Subwoofer Box Installation

This installation article was prepared for by This box was installed in a 1998 Ford F-150 SuperCab truck ( Webmaster’s truck). For more details on the truck click here.

As you can see, everything you need comes included with the box:

I also ordered two 10” Cadence UltraDrive Z subwoofers from Andy at

Picture of everything received - subwoofer box, subwoofer, other parts

You’ll need a few basic tools to install the box. I needed Torx bits, a ratchet and extension, and some screwdrivers. Luckily, you don’t need any specialized, expensive tools for this install!

The first step is to remove the rear seat. That is done by removing 10 bolts. Two of the (bigger) bolts are at the back of the seat; there are three on each end of the seat, and two at the middle support brace. In the picture below, the bolts are circled in yellow. You don’t need to flip the seat down to remove the bolts, but it makes the job easier. When you put the seat lift kit and sub box in later, however, you will not be able to leave the seat flipped down to put the new bolts in.

Bolts that need to be removed are circled in yellow

Once the bolts are out, you should be able to remove the seat. Be sure to flip the seat back in the normal (locked) position before removing the seat from the truck, to make things easier.

Seat bottom unbolted, and ready to remove

The next step after removing the seat is to remove the center brace that supports the seat. Although you won’t need the brace anymore, don’t worry that this is being removed. There will still be plenty of support for the seat provided by the strong sub box.

Rear seat bottom & bracket removed

Once the seat is out, the truck is almost ready for the subwoofer box. I did a trial fit, and it looks good!

Trial fit of subwoofer box

The next thing I did was mount the two Cadence subwoofers I ordered from I used the crimp style connectors because I didn’t have my soldering iron handy. I would highly recommend soldering all connections. Once I had the sub wired to the speaker connections inside the box, I screwed the sub into the box using 1/4" wood screws.

Subwoofer ready to be screwed onto box

Here is a picture of the sub box with the subs installed, ready to go into the truck:

Subwoofers mounted in box, and ready to go in the truck

The next thing I did was run the speaker wiring through the truck. This part is totally up to you as to how you do it. My amp was located under my passenger seat, so I simply ran a few feet of wire. Your application may be different. Then, I put the sub box in the truck and hooked up the wires. I used gold plated connectors. You can see how the whole unit looks here:

Box in the truck

The next step is to put the box in its final place, and put the seat back in. This part is a little tricky because there are four spacers that are needed to raise the seat two inches. Two of the spacers are wooden blocks (one at each end of the seat), and two spacers (metal tubes) are used at the back of the seat (where the larger bolts are).

I started by putting in the back two bolts first. This is where I needed to use my ratchet, extension, and wobble socket to get behind the seat to get those bolts in. It’s a tight squeeze in there, but it works! Don’t forget to use the two longer bolts that come with the seat lift kit.

Putting in one of the larger bolts at the back

Once the back two bolts were in, I installed the two wooden spacer blocks, one on each end of the seat. I used the enclosed (longer) bolts to replace the factory bolts. You can see the two blocks below:

Passenger side seat lift bracket

Driver side seat lift bracket

The only thing left is to put a few screws in place where the old middle seat bracket was. The screws go right into the box, securing the seat and box together. The seat was already really snug, so I’m not ever sure it needed the screws, but I put them in anyway.

Here is the finished product. It looks good – the tan carpet on the box blends very well with the factory tan carpet. More importantly, it sounds good. The installation took about 3 hours for me. If I wasn’t taking pictures, it would have taken a bit less.

Finished product!