How do i find Port Length?

[Anonymous 10+ year member]

My boxes external measurements are 40.25"W x 34"L x 17"D. So internally the box is 38.75"W x 32.5"L x 15.5"D. I am trying to find my port length so i can figure my tuning freq. The box ends up to be 11.3 cubes before port displacement. My port is 6"W x 32.5"L x 16.25"D. When i say wide i mean from drivers side to passenger, length is from backseat to hatch, and depth is how far the port goes straight down in the box. Someone tell me how to find port length. So i can plug it in to BassBoxPro6 and hopefully find my freq.

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[PatFitz9 10+ year member]

not to sound like a douche, but the port length is the length of the port. inside the box that is.

 

[Anonymous 10+ year member]

So the port length would be 32.5"?

 

[Anonymous 10+ year member]

What you mean by inside the box? How would that be any different than the length in the cross sectional area?

 

[Ingleside 10+ year member]

cross setional area is the area of the port opening. if your port is 3 inches wide and 15 inches high then your port area is 45 square inches.

check out this diagram to figure everything else out. i'm not really following you.

don't know if it will be usefull but check out these links to help you calculate everything.

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

http://mobile.jlaudio.com/support_pages.php?page_id=165

 

[Ingleside 10+ year member]

it seems like your port is 6 inches wide and 16.5 inches high giving you 97.5 square inches of port.

 

[Anonymous 10+ year member]

Nah i know my area is 195 square inches because the cross sectional is 32.5 x 6 that is the port opening. How would i find effective port length that diagram does not help me, i am not good with pictures.

 

[Anonymous 10+ year member]

Can someone explain that diagram to me or give me a formula or tell me what I need to measure to find my effective port length? Please

 

[machburger]

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

Using this calc and your supplied info, I came up with about 35.5 hz

 

[PatFitz9 10+ year member]

Nah i know my area is 195 square inches because the cross sectional is 32.5 x 6 that is the port opening. How would i find effective port length that diagram does not help me, i am not good with pictures.

dude it is written in the picture... B: first port length and A: second port length as long as you can read, the picture should help you. your port shouldn't be just a cut in the wood. there should be walls going into the box. that view is from the top, with the top sheet removed. if you didn't build the box, you might not be able to measure the other wall length. outside dimentions don't help with this length.

 

[tRiGgEr 5,000+ posts]

How do i find Port Length?

My port is 6"W x 32.5"L x 16.25"D.

There ya go.

 

[Anonymous 10+ year member]

so it is 16.25"

 

[tRiGgEr 5,000+ posts]

so it is 16.25"

Yes sir captain obvious.

Playing

 

[Anonymous 10+ year member]

man that can't be right i use that as my port length and it says my box is tuned in the mid 50's. Which i know is wrong because my subs would already be blown if it was tuned that high.

 

[Ingleside 10+ year member]

sorry.. just got to make sure that you're getting this to eliminate any confusion.

this is port length:

this is port area, L x W = area