How do you calculate cubic feet? I want to make me a speaker box.

 

Let's say you want to make a box that's 31x12x14. Just multiply these together (LxWxH) and devide by 1728. This will give you cubic feet. So (31)(12)(14) equals 5208. Your box is 5208 cubic inches. 5208 devided by 1728 equals 3.01. Don't forget to take into account the thickness of the walls of the speaker box (only use internal measurements), any bracing materials, and the speaker basket itself. A lot of companies will give you the basket volume in square inches. Just subtract the square inches from the square inch total before dividing by 1728.

Tony

 

Internel measurement of Height x length x width= total cubic inches Divided by 1728 dividided by the number of drivers and minus any braces.

 

Thanks, that sounds easy enough. I appreciate it.

 

There's a nice little program that does all the calculations for you called WinISD. And heck its free. Only drawback is that you might have to put in all the Theil information for a newer sub (the Xmax, Vas, all those nice looking things that make no sense... well they do, but they can be pretty confusing). But the program will give you the optimum dimensions. You gotta check sometimes. I had a 12 inch sub, and it told me to make the width 13 inch or some junk like that. Hmmm, doens't seem very smart to do that! Anyway, it also gives you SPL output.

 

i use winisd sometimes also. but don't think that the spl gains, are what you'll be getting. it doesn't take into factor the vehicle and other factors.

 

True, but it'll be good if you want to compare two subs with the same amount of wattage and see which one will be louder.