Looking at put a single 12" sub in my wife's 1992 firebird convertible. Does anybody have dimensions for a simple box to fit a single 12?

 

The convertible's well and sides will be the same dimensions as a hardtop. The dimensions or rather internal capacity that you will need to build to will vary based on the subwoofer's technical specs. I believe that it's the Qvas number that you are looking for. Some subs require 3 cu ft of air space while some of these low profile ones will only require 0.75 cu feet.

 

It's a small sub going in. Cheap walmart sub

 

Still need the Vas number. You use a sealed box that is too small and you risk blowing the sub or the box. Use a box that's too big and it has an effect of quieting it down.

 

Not much room back there.I tried to fit a single 12" sub, but decided it would take up too much space.Went this route instead.

 

What is that thing called? And how does it compare to a normal sub box?

 

Cerwin Vega VPAS12, there's also a VPAS12st.Doesnt thump like my old 12" CW subs, but combined with the 6x9s above it.The trunk works like a box of sorts.I dont crank it up like i used to, but the bass is more than enough

 

The trunks are the same size as the hard and T-tops. Here is a 1/2 width single sub box I made and here is the thread I made a few years back about it with the exact dimensions that you are looking for: https://www.thirdgen.org/forums/car-...ell-width.html
You really need to use the search feature for more

 

Yeah, half size.Try getting a full sub box with two 12" in there.Even the cargo lid with 2 subs is a pain.Let alone trying to use it.

 

You can find 10s and 12s now-a-days that have very similar box requirements and if you weren't able to you could just biuld the box a little taller or wider. With the performance of modern speakers a regular guy doesn't need a pair of 12's with a huge box to get a good thump.

 

Partly why i chose that vega thing.It does the job fine and i wasnt willing to loose what little trunk space a vert has.

 

I built a box so that my amp sits on the driver's side bottom of the trunk well and the speaker box sits on the passenger's side. The height of the box and width of the box gave me the internal box dimensions I needed for solid bass and I extended the box top piece over the rest of the well where the amp lives. It gave me a flat surface for the trunk bottom that now goes from inside the driver's side rear fender to the passenger's side map pocket (spare tire well). Simple and effective.