Double checking my numbers

[ebrunn 10+ year member]

I am trying to design a box for a friend that has 2 15" Power Acoustik Fubar's. The specs on them are that it needs a ported box at around 3 cu.ft and I was going to tune it for around 34hz. I read the tutorial on the top on this section about doing it with WinISD and so thats what I did.

For net volume I used: 6.0 cu.ft

Port area: 3 inches wide by 15 inches high

Tunning:34hz

My max dimensions were: 40 inches wide and 16.5 inches high

Product of remaining two sides:660

Using WinISD I got a Port Length of: 10.55 inches

I used that to figure out my port displacement:

((3+.75)*15*10.55) / 1728 = 0.34

Then I came up with my gross volume:

Net Volume(6.0)+Port Displacement(0.34)+Sub Displacement(.123)=6.157

Then I solved for my remaining side:

S= (6.157 * 1728) / 660 =16.120 inches

So we got:

Internal Dimensions:

40 inches wide x 16.120 deep x 16.5 inches high

Net Volume:

6.0

Port Area:

3 inches x15 inches

Port Length:

10.55

Am I doing good so far?

This is my first time using this way to do it. I usally use the calculator on Subwoofertools.com.

Thanks in advance for any help.

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[Trixter 10+ year member]

using the formula in my sig i came up with....

if using 6.0cu' net, port area of 45sq" and tuning of 34hz....port length is 12" add the end correction factor (if port shares a wall with the box) of 1.5" (1/2 the port's width) to get a 13.5" long port.

the displacement of the port would be.....

12.75 L (don't count the 3/4" for the face of the box since we're already using int. dims.) x 3.75 W (also the same with the port wall that shares a box side) x 15 H = 717.18 / 1728 = .42cu'

so we're at 6.42cu for total net volume....add you sub disp. which you said was .123 now we have 6.54cu' box.

using you max dims., now play with the numbers to get 6.54.

 

[ebrunn 10+ year member]

thanks alot for the help