why is port diameter important?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=119646
Printed Date: April 27, 2024 at 12:51 PM
Topic: why is port diameter important?
Posted By: rfhvhtoo
Subject: why is port diameter important?
Date Posted: January 26, 2010 at 1:36 AM
Why do people suggest larger port diameters? when you can get the same tuning with shorter length at smaller diameters and less displacement?
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Replies:
Posted By: Steven Kephart
Date Posted: January 26, 2010 at 2:54 AM
Because a smaller port diameter will have higher air speeds to allow for the same amount of air to flow. Higher air speeds in the center along with friction along the walls of the port and the resultant slower air speed in that area cause a chuffing sound. That is also known as port noise.
Posted By: kanarrjl
Date Posted: January 26, 2010 at 9:04 AM
also because up to a point (depending on your application) it will increase your spl numbers.
Posted By: incognyto
Date Posted: January 26, 2010 at 9:12 AM
Now knowing this is it possible to make a box specificly for spl but make it easy to convert it to sq??? Swap tube ports legnths??
Posted By: kanarrjl
Date Posted: January 26, 2010 at 9:16 AM
incognyto wrote:
Now knowing this is it possible to make a box specificly for spl but make it easy to convert it to sq??? Swap tube ports legnths??
generally a spl setup is about 16square inches of port face area to every square foot of box space and is tuned high (50-70hz) and a sq setup is around 10square inches of port and tuned low (25-35hz)
Posted By: incognyto
Date Posted: January 26, 2010 at 9:21 AM
So with that I can build a box for spl with a large port and Maybe have a divider in thAt port so part of it could be split off and sealed making the port area smaller?? Or would the lenth have to change also???
Posted By: kanarrjl
Date Posted: January 26, 2010 at 9:56 AM
to some extent that may work it depends on your aplication give me some numbers then i could help you out
Posted By: incognyto
Date Posted: January 26, 2010 at 12:20 PM
I have the PDF at home for the ts
parameters but it's fir the 15" alpine type r
Swr-1542d
I have 2 of them And I put them in my box that I made fir my jl audio 12's to jl specs I'll post those dimentions too bit apparently it's 3.5 cubic feet total when I measure the box I get 5.5 without takin the ports out of the measurement
Posted By: rfhvhtoo
Date Posted: January 27, 2010 at 1:59 AM
im getting the calculation on carstero.com that I should not have a port Diam less than 7.69inches. done this mean that 2 4inch Diameter ports give me 8 inches in Diamter of port?
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Posted By: kanarrjl
Date Posted: January 27, 2010 at 8:27 AM
rfhvhtoo wrote:
im getting the calculation on carstero.com that I should not have a port Diam less than 7.69inches. done this mean that 2 4inch Diameter ports give me 8 inches in Diamter of port?
No. 1-4" port is 12.56 square inches. Then take that x2 and it gives you what 2 of them would be 12.56x2=25.12 where as 1-8" port is 50.26 square inches. Basically you would need 4-4" ports.
Posted By: rfhvhtoo
Date Posted: January 27, 2010 at 11:57 AM
kanarrjl wrote:
No. 1-4" port is 12.56 square inches. Then take that x2 and it gives you what 2 of them would be 12.56x2=25.12 where as 1-8" port is 50.26 square inches. Basically you would need 4-4" ports.
Does 4, 4" ports sound reasonable for 3 ten inch subs though? ------------- I can't hear you!
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