# 4th order / jl12w7 serious help.



## enerlevel (Jun 6, 2009)

i used winISD fo calculate ....... i am confused.
according to the software.

sealed chamber : 2.162cubicfoot
front/ported chamber : 1.122 

but isnt the front chamber suppose to be bigger then the sealed one???? 


for the vent it says 

1 round (port) 4" diameter and 16.75" LENGTH tuned to 39hz.


isnt this just to small ? on 4th orders , arnt u suppose to use big ports which fire through the rear deck or arm rest?


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## 8675309 (Jan 8, 2007)

This is all internal
Chamber 1 = 1.5
Chamber 2 = 1
Port = 4 round 17 long 

Depending on your power you may get port noise. 

Around 600 you should be okay


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## 8675309 (Jan 8, 2007)

Sorry I forgot to give the exact info,. The port needs to be in chamber 2


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## aznboi3644 (Jan 25, 2009)

ported chamber does not always have to be bigger....the volumes can be manipulated with tuning to get whatever response you want.

Also for the port I would use atleast a 6" round port if you are going to use round ports...if using slots I would go for more port area.


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