Need a double check on my port

[Alex K]

What you have drawn there looks way off. . .

1. a 3.5" opening inside the box is not correct if the outside opening is 4".

2. the program says you need a 22" port, you have drawn a 40+ in port.

3. from your commenst, you are mixing up port length and port area. . .

For the 31 x 25 x 16 dimensions you posted, you need to just get rid of the back port wall and make a port from the single 20.25" dimension (into the box so it is 4" from the back wall).

I would also double the baffle making it 1.5" thick.

The result is 4.5 cuft tuned to 32 Hz.

Brian

Explain to me some more. I get what you're saying but every little bit more helps. I think I am getting confused on port length... Ay help at all whether it be actualy dimensions or something like that I would love you forever.. No homo..

EDIT:

I think I finally get what you mean. So is this correct?

Edited May 4, 2010 by Alex K

[Alex K]

Lol, is that correct?

[bkolfo4]

You have to add the length through the center of the 90 degree bend too.

You have a 32.75" port there.

If you just put the 19.5" piece in there, and then add the length through the 90 degree bend, you have 25".

Any time you stop the port wall so the opening between the port wall and the back of the box is the same dimension as the port width, you add the length through the center of the bend.

[Alex K]

I really still don't understand... Could you maybe construct the port for me? Or maybe give me a little more detailed info?

[bkolfo4]

I really still don't understand... Could you maybe construct the port for me? Or maybe give me a little more detailed info?

I think I have already said several times that using the 19.5" piece results in a 25" port. . .

Does this help you see it?

[Alex K]

So that's all I need? Just a 20.25 inch piece? No L shape at all? How come I see some with an L shape? I thought most ported used that kind.

Final dimensions and etc. Do THESE finally look right?

[bkolfo4]

I do not want to offend anyone, but I have corrected a lot of boxes that this program has calculated. I have yet to see a perfect program for L-shaped ports.

I can check on the latest dimensions it gave for your box tomorrow.

Brian

[bkolfo4]

Just ran in here and checked the dimensions.

If you build the port as my picture shows above and use the overall dimensions of 13W x 16H x 25D, assuming .21 driver displacement and a double baffle, you end up with 4.5 cuft net volume tuned to 32.5 Hz.

If you want it tuned a little higher, knock 1" off that port wall length.

I woudl also roundover the edges on the inside end of the port wall before you install it, and then roundover the port opening on the outside of the box.

[Alex K]

Yes I was going off your picture you gave me. And yes I will round the edges. That won't throw off any tuning will it? And again that picture you gave me is with a 31w, 25 depth, and 16h correct? That should tune it to 34 hrtz, considering all the displacement of bracing, & double baffle

[bkolfo4]

Yes.

Depending on how much bracing and how much you round the port edges, you will be between 33-34 Hz tuning.

Brian