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View Full Version : How do you measure......?

tooshort_128
01-30-2009, 01:45 PM
How would I determine how many square inches of port I have if I'm using a round port? For example, a 4" port that is 13.15 inches long.......

dman4486
01-30-2009, 01:46 PM
area of a circle:fyi:

http://www.geocities.com/kevinbisesser/AreaOfCircle.html

snb778
01-30-2009, 01:47 PM

James Bang
01-30-2009, 01:47 PM
pirsquared

IDSkoT
01-30-2009, 01:48 PM
But, you need a considerably less amount of space when using a round port as apposed to a square port.

dman4486
01-30-2009, 01:50 PM
read post 2, 3 and 5 as if one post and there you have it:laugh:

tooshort_128
01-30-2009, 02:01 PM
thanks guys! seems like I won't have enough port area......

tooshort_128
01-30-2009, 02:11 PM
hold up....I'm confused. I got the whole area of a circle thing but it's actually a tube....

terra
01-30-2009, 02:13 PM
Area and volume are seperate..

tooshort_128
01-30-2009, 02:17 PM
this is true.....If I need about 32 square inches of port and I have a port that is 4"x13.15" long, how many square inches is the port? Pi x radius^2 would give me 12.56 correct?

mlstrass
01-30-2009, 02:27 PM
pirsquared

Sorry JB, but pie r round, cornbread are square :D

mlstrass
01-30-2009, 02:28 PM
yes a 4" port is 12.56^2 of port area. Generally if using aero ports you can get by with about 1/2 of the port area of a normal slot port...

Buck
01-30-2009, 02:30 PM
yes a 4" port is 12.56^2 of port area. Generally if using aero ports you can get by with about 1/2 of the port area of a normal slot port...

Why is this?

tooshort_128
01-30-2009, 03:09 PM
yes a 4" port is 12.56^2 of port area. Generally if using aero ports you can get by with about 1/2 of the port area of a normal slot port...

Oh I see, so in this case I still need a little more port correct?

budahbuddy803
01-30-2009, 03:15 PM
yes a 4" port is 12.56^2 of port area. Generally if using aero ports you can get by with about 1/2 of the port area of a normal slot port...

wouldnt it be (pi)(r^2)(height) when looking for volume at least? so 12.56x13.5=168.75...???

BlkColly
01-30-2009, 03:26 PM
2 ports @ 4-1/2" diameter will give you as close to 32 in^2 as you're gunna get

tooshort_128
01-30-2009, 03:30 PM
yeah, but they'll be hella long...

rumblebee2
01-31-2009, 12:36 AM
yes a 4" port is 12.56^2 of port area. Generally if using aero ports you can get by with about 1/2 of the port area of a normal slot port...

yes mlstrass why would that be? not saying you are wrong just wondering.

tooshort_128
02-10-2009, 11:18 AM
So if I can get away with half the required square inches of a slot port then I could do about 6^2in. per cube. If the box is 2.34 after displacement then I'd need 14.04in^2. One 4" at 14.15 inches would give me 12.56. Is this close enough?

snfsh79077
02-10-2009, 01:05 PM
I am wondering the same thing about aero ports. If it is true that you can get away with half as much area then I would think for 2-2.5 cuft boxes 1 4-4.5" aero port would be sufficient for one driver.

tooshort_128
02-10-2009, 01:44 PM
Well, snfsh79077 agrees with me. Anyone else think this is okay?

snfsh79077
02-10-2009, 01:50 PM
Well, snfsh79077 agrees with me. Anyone else think this is okay?

Im just going off hear say lol but I was just recommend by someone 8-12" per cubic foot.

shaneb
02-10-2009, 01:51 PM
Just take a saw and cut some holes in the box then it's ported. None of this other crap matters...

SSS 18734
02-10-2009, 01:53 PM
Port noise is a result of the friction between the port walls and the air flowing through the port. Round ports generally need less port area because they minimize this surface area.

snfsh79077
02-10-2009, 01:53 PM
Just take a saw and cut some holes in the box then it's ported. None of this other crap matters...

haha will do

roarzorz
02-10-2009, 01:57 PM
8-12" per ft of net volume is a general rule for round ports. For a single 12" in 2-2.5ft net volume I recommend two 4" ports.