possible to get a hairtrick? maybe someone could help?

[Ben G.]

Well, there´s a very simple rule on port area, 12-16 SQ of port per each cubic feet, it´s very good if it´s a simple box, but there are subs that likes smaller, others bigger, for example, my DD´s LOVE at least 16 SQ of port per cubic feet; Also, depends on the power, if it´s a small power you don´t have enough for a big port and viceverse.

Said that, you find out how much internal space you want for the box, you get how many SQ of port you need, and the tuning just use the12volts.com or any other online calculator for the port depth, that´s pretty much it, of course, it´s way more complex than that if you are competing or something, but for a simple box, that´s the easiest way...

Wow, I've asked people before and they blow me off!...Thanks A Lot man! I appreciate this soooo much. I can do anything as long as someone explains it to me. So the formula i should use is: (12-16SQ "s X Cubic feet of inside measurments of the box = Port Area.)So if i had an: 8 cube box and whent with 14 SQ of port area. It would be 8 X 14= 112sq inches of port area? Is this correct? This was just a quick, off the top of my head.

[n8ball2013]

square are of port is length x height. a 10x10 port would net you 100 sq inches of port.

[fecupe2001]

Wow, I've asked people before and they blow me off!...Thanks A Lot man! I appreciate this soooo much. I can do anything as long as someone explains it to me. So the formula i should use is: (12-16SQ "s X Cubic feet of inside measurments of the box = Port Area.)So if i had an: 8 cube box and whent with 14 SQ of port area. It would be 8 X 14= 112sq inches of port area? Is this correct? This was just a quick, off the top of my head.

hehehe no worries dude, glad i can help you, i forgot to tell you something, this 12-16 SQ per cubic feet applies on the slot ports, aeroports are more efficient and need less area, something like 9-12 SQ per cubic feet. I´m gonna explain you with an example:

Let´s say you are building a box for 2 12´s and you want a daily box that sounds good with anything, the subs are kicker CVR´s and you have 1200 watts. I would want to use 4 cubic feet after displacements (port, subs, bracing, 45´s if you use them, etc). For that kind of power and daily box, i would use 40 hz tuning and around 14 SQ of port per cubic feet with a slot port; If i want the box to be 4 cubic feet i need to make it bigger so i can get 4 c/f after displacement, let´s say each sub has 0.12 c/f and i would get around 0.3 c/f of port, then í would need around 4.6 c/f BEFORE displacement.

Let´s say my measures are 14H x 33W x 22D , i´m gonna use them for my box, they are external dimensions

14 x 33 x 22 / 1728 = 5.88 c/f EXTERNAL

We have to take out the wood thickness so we can know the internal space, since it´s 3/4" MDF then we have to take out 1.5" to each measure so we can get the internal space

14-1.5 x 33-1.5 x 22-1.5 /1728 = 4.67 c/f INTERNAL

The subs are 0.24 c/f , so , 4.67 - 0.24 = 4.43 c/f

The port:

We said we want around 14 SQ per cubic feet, if we are calculating 4 c/f after displacement, 4 x 14 = 56 SQ of port it´s what we need.

We want a vertical port, the box internal high is 31.5" , that would be the port high, 56 / 31.5 = 1.77" wide would be the port, i would get 1.8 then.

Now i go to http://www.the12volt.com/caraudio/boxcalcs.asp and put in these measures, it says that, for 4 cubic feet internal and that port area, i need to get the port 17" depth for a 40 hz tuning, if you want a higher tuning then the port depth is shorter and viceverse.

Finally, we can know the port displacement would be like this:

31.5 x 1.8 x 17 /1728 = 0.5 c/f

4.43 - 0.5 = 3.93 cubic feet after all displacements with a 40 hz tuning and 14 SQ of port per cubic feet, i think that would be a kick ass box for daily pounding on 2 12´s and 1200 watts, i hope this can hellp you!!!