With premade boxes, make sure you have the mounting depth you need for the subwoofer you are thinking of using.
Here is a Savard 10 inch RAP series subwoofer and they have listed the necessary mounting depth along with many other pieces of information needed.
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You may find that you have to use a less powerful or a smaller woofer to fit you vehicle needs.
Here is a smaller 6.5 inch woofer that still needs 4-1/8" inside the box for mounting.
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Long ago in 1996 I had a 1982 GMC S-15.
My brother was into car stereo so by proxy, so was I.
I bought a set of PPI Art Series amplifiers and a set of Kicker 8 inch Solo-baric subs.
Being 6'2", my seat was all the way back when I drove my truck.
I had to build my boxes to be able to mount the sub as well as having the required internal space the sub called for.
Tall and narrow boxes for sure, but built like tanks from 3/4" particle board.
I only have some screen shots from a video my buddy took to show them, but you get the idea.
If you really want it to be done, you will figure a way.
The image shows when I was running an Alpine V12 amp before I was able to fully purchase the other PPI.
I still have all this stuff except for the sub boxes.
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