View Full Version : Check my numbers

11-15-2005, 07:43 AM
Well Ive already cut all the pieces, but these numbers should be right.

Here we go.......

This is a ported box for my SX 15.

As RE says, make it 3.5cuft @ 32hz

I got these measurments 34"x13x18" and that gave me 3.56cuft net.

I then calculated port disp. -
Port is 32hz
Take the length and subtract .75 and then multiply by the height and then multiply by the width+.75 and then divide by 1728

Which is 1.07cuft for the port disp.

Sub Disp is 0.18cuft.

Now, I have my net volume, and my displacements, now I need my gross volume and I get that by adding up the net and displacements.
Which is

So my gross volume is 4.81 cuft.

Now I adjusted my measurments to compensate for this.
Which is now
35.5"x13"x18" = 4.807, and when you do significant figures it comes out to be 4.81cuft.

Now, all I do is build to those measurements and that will give me 3.56 net in the box when I add port and sub, correct?

11-15-2005, 12:19 PM
If those are external dimensions then the box will only have a gross volume of 3.73 ft^3

Didn't check the port, but you should focus on the right size first. If they are internal dimensions then you're okay if I assume the port calculations were correct.