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Port calculator w*h

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Old 07-29-2010, 02:29 PM
  #21  
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In your drawing, the virtual port line would extend from the end of the inner wall up and to the left to the outer wall at a 45deg angle.

If you need a vent that is 20" long, and the vent is 6.2" wide, then cut the inner wall 3.1" shorter, ie 16.9" long.

If you leave the inner wall at 20" long, then the vent will, theoretically, behave like it is 23.1" long.
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Old 07-29-2010, 03:12 PM
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Does the 12volt calculator calculate for half the port width? Meaning, should I calculate it as 20" long, then make it shorter for what it calculated and expect the same tune? I want it at an actual 34.9 HZ.



I change one thing and everything else changes >.<

Last edited by Lord Huggington; 07-29-2010 at 03:42 PM.
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Old 07-29-2010, 03:47 PM
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Originally Posted by rbgnwa45
I change one thing and everything else changes >.<
awww, the joys of enclosure design... There's a lot more to it than people think.
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Old 07-29-2010, 03:55 PM
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LEFT, not right. Sorry about that - my bad..

Calculate it as 20, then shorten it when you build the box. Bear in mind though that nothing you do with a calculator or computer program will get that box tuned to 34.9hz. There are simply too many variables. The only way to tune to a *specific* frequency is to test it and re-tune after the fact.
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Old 07-29-2010, 04:41 PM
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Is 12.21 square inches per cubic foot okay?



F'in magical .

Last edited by Lord Huggington; 07-29-2010 at 08:19 PM.
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Old 07-30-2010, 03:01 PM
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Only if you have over 200watts per armrest..
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Old 07-30-2010, 07:17 PM
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Just seems low.
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Old 07-31-2010, 11:05 AM
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Try using this vent area calculator and see what it says: VENT AREA
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Old 07-31-2010, 01:29 PM
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Good observation - that calculator calculated for the port angle:

17" long = 33.87 HZ

The 12volt's doesn't.
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Old 07-31-2010, 02:19 PM
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What did it say about port area?
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