need some help

Designing a completly custom box for a 97 cavalier z24............ Im putting 2 alpine type r 1241d's in it, with a 500s rockford amp..... i want a closed style box, i have some dimensions figured out, and i know what i want it to look like, im just in a jam as to what to do next, im not sure about proper acoustics of the box, and taking away from the quality of the speakers........ my box is simple, allthough using a piece of plexiglass on the back, so the magnets can be seen, and mirror stuff on the inside, with a neon lite....... i need advice as to some dimensions, i came up with 31 inches wide, and 16 inches tall, there is a slight slant on the front, i need to know the top depth, bottom depth, and the length of the slant piece.......... Thanx for any help...... Cavz24 R

I guess I am a little confused, but it sounds like you are saying you have a rectangular box - except when viewed from the side, it's more like a triangle on top of a rectangle. You never actually gave all the dimensions (that I could tell), but to figure volume .... do the rectangular part first - it's just HxDxW from the BOTTOM of the slant on the sides. Then add the top half, it's 1/2 x H x W x D. Remember to subtract the volume of the subs that are inside the box.

look at the recommended cubic in area that the speakers need to sound right, with that info you can design your box anyway as long as you have the right surface area.