to much port area?

[bkolfo4]

Not sure. Never used it and have corrected designs for people from just about every popular calculator out there. Sometime the person enters the data wrong, sometimes the calculator is wrong. Most of the time the calculators are only wrong when a L port is involved.

Edit - as I see in this case, you did not add the # of ports

Always best to go back and check the design before you build.

Prety easy - If you have the calculator results:

1. Figure out the overall gross volume (L x W X H of the overall box using internal dimensions).

2. Determine the port volume displaced inside the box.

3. Subtract the port volume and the driver displacement from the gross volume to get the net volume.

Plug in the net volume and port size into something like this:

http://www.carstereo.com/help/Articles.cfm?id=31

Make sure the port length give by the calculator matches the required port length from the calculator above.

I took your box -

33.5 x 41.5 x 16.5 = 13.27 cuft gross

Looking at your ports, I assumed: 8.75 X 8.75 x 2.25 for the 2 outer ports and 8.75 x 9.5 x 2.25 for the center = .20 cuft

Just guess ~.25 for driver and bracing

Leaves ~12.8

Plugged that into the port length calculator until I found the ports needed to be 33" long, and at the length they are, you are tuned to 65 Hz.

[t-money]

the yellow area accounts for the 2 ports that are using 2 common port walls

[LoudNLow931]

It doesn't work like that... Like he said the ports are not just taking up space like bracing.

[t-money]

that only accounts for one port your box has 3

i know that. thats what the .54 in the bracing area is. the displacement of the other 2 ports

You realize air goes through those other two ports. They're not just taking up space in the box.

yes but if all the ports are the same size and length it takes up room in the box, so that changes your tuning a little but it also gives you more port area right

[LoudNLow931]

This is what it should be...(Except less bracing probably)

[MarioB]

This is what it should be...(Except less bracing probably)

^ this

[MrSkippyJ]

yes but if all the ports are the same size and length it takes up room in the box, so that changes your tuning a little but it also gives you more port area right

it changes your tuning by a bunch

[ChevyBoy95]

ok.... it is 3 ports, meaning 3 8in by 8in holes that are 3in deep (or 8x8x3). So to calculate tuning, it is 8in tall, and 24in wide (or 8in times 3 because there is 3 ports), and 3in deep. Put it in and you get a shitty tuning.

[t-money]

ok well how would you tune it low. like 30 to 32 range. say u can replace the entire port wall

[bkolfo4]

Can someone tell me how the calculator got the port volume? It says .30 cuft. An 8x8 port 3" long (2.25 internal which I see it knows) would be 9.5 x 8.75 x 2.25 = .108 cuft.

It throws off the net volume a little. Not a lot in this case, but like I said above I have seen several times where it gets off pretty good on L ports.