ok so i really dont trust most of the box calcs. online so i've been researching formulas and anything i need to know about designing on my own. so anyone with advice please put in your two cents.....

tell me if i got this much figured out:

1). to come up with the ft^3 of the box you multiply length x width x height using the inner dimensions. then take the total of that and divide by 1728 which is the in^3 of 1 cubic ft.

2). then to factor in port, bracing, and driver displacement you use the L x W x H on each item and subtract it from the ft^3

3). for box's with a slanted front. for example the top is 5" and the bottom is 15" you find the average of them by adding them 5+15=20. then divide by 2 20/2=10. use the volume formula with 10 and there's your cubic feet.

now for some questions

1). whats the formula to determine the tuning freq./port length on slot ported and round ports?

2). doin 45's in corners. when im factoring that in would i use the angled box formula to determine overall volume after displacement?

any info i can get would be great and much appreciated also if u know great links tor tips and tutorials please post up. once i get the tuning figured out ill make vids/tutorials on everything including kerfing.

so anyone with advice please put in your two cents.....

You tell us what is your subwoofer, we tell you what the box should be(dimensions, tuning, etc), you cut the wood pieces and glue it. I think that is one good option in front of you.> Advice from someone that already have done a box for the same woofer and is happy.

yeah well i wanna learn the art of box building not just a box for my sub. you know so i can build other boxes for friends and shit. but i've got a fosgate power hx2 15 if u can do me a design 4ft^3 kerfed port tuned at 33hz witth 45'd corners and double baffle that would be great......most people wont do a design like that free

Well I am on the same boat as you. What I can share with you is :

PORT Size Calculations and Formulas for WOOFER and Subwoofer BOXES

Subwoofer Vent Equations Formulas Calculator - Length Port

JL Audio - Car Audio Systems

1) The formula for tuning a box with a slot port is the same as with round ports. All that matters is the port area, not the shape. There are various places to find formulas, I think the end has pointed you to some.

2) To factor in displacement of the 45s in the corners, all that you need to do is subtract the volume of the pieces of wood that you put in from the gross volume of the box. Remember that the area of a triangle is just half of the area of the square/rectangle that its dimensions would give, so you just need to do width x length / 2, then multiply by the height of the piece. You don't need the angled box formula.