View Full Version : Help Box Guru's

Blaze98

01-08-2004, 03:48 PM

I have been checking out this board for a couple of days and you guys seem to know your stuff so I am here to ask for your help. I recently built my first sealed enclosure and I think I did a pretty good job, but I am not getting the deep bass extention that I did when I had a ported box. I have never designed a ported box before so this is all new to me, I put some specs together and I would appreciate it if someone would check my math to see if I am on the right track. The dimensions are:

H-17.5 in.

W-32 in.

D-14 in.

Port-2 in. wide x 16 in. high x 24 in. long

I am looking for tuning around 30 hz. The port will be opening on the side of the box as this gives me the best chance to construct a straight port. The box is 3.5 cubic in. before displacement of the subs and port wall for a total of 3.3 cubes total, 1.6 cubes per sub. This is going by the manufacturer's recommendations.

Any help would be greatly appreciated, Thanks in advance.

tommyk90

01-08-2004, 03:56 PM

I think you gotta calculate displacement of the port area as well. A box 2.75x16x24 is .61 cubes, so i think you will have to make the box bigger to get enough cubic feet for the subs.

So make a box that is 3.91 cubes after sub displacement(i don't know what the disp. is). When you do that the port will displace .61 cubes, which will make the box volume 3.3 cubes. Also, that will give you a tuning of ~30 hz, give or take a few tenths

(sorry to interupt your thread)

any idea on where i can find the equations for all this?

i know how to find the volume and that stuff, but where can i find out the port sizes needed to have a certain tuning with a certain size box?

tommyk90

01-08-2004, 04:35 PM

(sorry to interupt your thread)

any idea on where i can find the equations for all this?

i know how to find the volume and that stuff, but where can i find out the port sizes needed to have a certain tuning with a certain size box?

I believe its at www.linearteam.org. Download WinIsd Pro

LoneRanger

01-08-2004, 04:47 PM

win isd ***** for port calculations in most instances

you'll have better results with the eatel amptech site....i'ma put that freakin link in my signature...i hand out more links to his site than google!!

Blaze98

01-08-2004, 04:52 PM

win isd ***** for port calculations in most instances

you'll have better results with the eatel amptech site....i'ma put that freakin link in my signature...i hand out more links to his site than google!!

That is the site I used to calculate my port length, it is a very useful site.

Blaze98

01-08-2004, 05:03 PM

I think you gotta calculate displacement of the port area as well. A box 2.75x16x24 is .61 cubes, so i think you will have to make the box bigger to get enough cubic feet for the subs.

So make a box that is 3.91 cubes after sub displacement(i don't know what the disp. is). When you do that the port will displace .61 cubes, which will make the box volume 3.3 cubes. Also, that will give you a tuning of ~30 hz, give or take a few tenths

Just curious why you multiplied the equation times 2, I am only using one board and the wall to create the port. Should I include the wall of the enclosure into the calculation for the port?

tommyk90

01-08-2004, 05:08 PM

Just curious why you multiplied the equation times 2, I am only using one board and the wall to create the port. Should I include the wall of the enclosure into the calculation for the port?

I didn't multiply anything by 2. since the port is 2x16x24 and the wall of the port .75 inches thick, you have to take all of that into consideration for displacement.

tommyk90

01-08-2004, 05:10 PM

win isd ***** for port calculations in most instances

you'll have better results with the eatel amptech site....i'ma put that freakin link in my signature...i hand out more links to his site than google!!

I use both of them in conjunction. I couldn't use bcae.com for my box for some reason. So i use winisd to see what the port has to be and plug it in bcae to find out displacement and stuff.

I always use bcae to find out box sizes though.

Blaze98

01-08-2004, 05:19 PM

I didn't multiply anything by 2. since the port is 2x16x24 and the wall of the port .75 inches thick, you have to take all of that into consideration for displacement.

Okay, I see where I screwed up, I didn't include the 2 inches of port area into the equation when I calculated the displacement, thanks for pointing that out. You guys are very helpful.