We will be making TUBE boxes.
Main material is 3/4" MDF and Sonotube/concrete tube, both cheap and easily found at Home Depot. For around $20 you can get a 1/3 sheet of MDF, a tube, adhesive and screws.
Find a tube big enough for the sub
Doing a little math after finding the sealed space requirement for your subs you cut your tube to the right length. For me my space was .28 cubic foot, so the 8" tube minus space for the inserted MDF equates to around 11" of tube.
then we cut some insertable plugs. a sealed one for the end and a additional mounting brace for the sub. you want these TIGHT to fit in the tube, I put a slight bevel on the edge so they had to be tapped into place.
Rough up the inside of the tube with some sand paper to break the waxy coating and to give the adhesive some tooth.
Nice bead of adhesive
and tap the end caps and rings in place
Now for the true end caps there is many ways to skin this cat. you can just make end caps the same OD as the tube or whatever. Guys are even making down firing stands for home theater on the front, its all up to you.
For me I made my ends also my mounting stands. Both ends are the same just the front has the mounting hole. The rears are glued and screwed to the back plate (overkill) and the fronts are glues and clamped. You can never have too many clamps
The reason for the beefy end caps is that is getting the most impact of pressure. The tube should not flex in my setup but in a 12" you may have to make internal braces just to be safe. it would just be another plug but cut all gusset like and shit.
Well these have to dry and today when I get home I will cover and mostly finish them.