Had a sub enclosure question 2006 Dodge Dakota

[the moose]

I trying to look at different options for the back seat of a dodge dakota crew cab besides a flat enclosure underneath the seats, they also still want use of back seats. I need .85 cu.ft. for a sealed or 1 cu.ft of airspace for a ported enclosure using single 10" sub. I was thinking of making a turned clockwise on it's side "L" shaped sub box / arm rest for the middle of the back seat area.

I was wondering if there is a calculator on the web somewhere for odd mdf boxes or will I have to resort to using packing peanuts to measure out the cu.ft ?

[the moose]

Ok, going to make it easier, I'm thinking of making this type of box. The seller of this enclosure does not post any useful dimensions to the public so it seems, they sell them for $160.00.

So I am measuring 6" ( front to back lower bottom / on the floor) 20.5" (front to rear) x 12" (wide) x ?" (high) for now need to make more measurements of the backseat of his truck to try and level it to the front storage box.
Plus has anyone ever made a sealed box that fires into a slotted port before?

there is also this slot port option that I just found (which sells for $189.00), Luckily it does have basic dimensions to it. I could probably build this one for about $25.00 MDF and carpet.

[the moose]

I figured it out okay, my enclosure came out to be 1.07 cu.ft. and I used a 3" round port roughly 10" long