# help with subwoofer



## Sirvint (Dec 1, 2011)

yes i have a morel uw-958 9" ultimate subwoofer (39.5 lt. vas ) and am pairing it with a css-pr12 i have the box configured with 1.38542 cubic feet that is about 39.23072617074 liters ? is this about correct? and will one 12pr be ok? or will i need 2? ( i had heard you need it to be just a little under the total volume of the sub for this to work) ( width-15.75" height-12" depth-17.50" thickness-.75" = 1.38542 cubic feet )


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## Mike P. (Apr 6, 2007)

Welcome to the forums! What amp will you use? Is the 1.38 cu.ft. the net internal volume after the deductions for driver, PR, and bracing have been made?


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## Sirvint (Dec 1, 2011)

hi my amp in the car is a pyle super power pla2988 a 6000 w bridged but for an 8 ohm speaker i probably will only 3000 or less that is ok the speaker is only rated at 500w 1500w peaks and i have heard i need about two to three times the power for dynamic head room. according to the moral specifications the eq. cas air load (liters) says vas- 39.5 lt. and no i have not calculated 1.5" total thickness of all 4 sides of sound rubber or the crossover or pr - will use corner brace brackets inside.not sure if i am going to put the crossover inside or mount it outside on the side of the box.


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## Mike P. (Apr 6, 2007)

Is this sub for your car?


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## Sirvint (Dec 1, 2011)

yes


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## Mike P. (Apr 6, 2007)

You need to figure out what the net volume of the box is going to be and see what tuning frequency would work best.


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## Sirvint (Dec 1, 2011)

question? for the css 12pr what is and/or about frequency for pr-12? 8hz-10hz? 10hz-20hz? 
when i test a 20hz signal then the pr12 by volume should creat a 10hz wave or somewhere there about?


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## Mike P. (Apr 6, 2007)

If you are asking what the resonant frequency of the PR is, it is 25 hz.


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## Sirvint (Dec 1, 2011)

thanks. i will get with the speaker builder of the box together we will find out the total volume of the box but will not see him this week. a week and half from now that is a week from next tuesday i will keep you up to date with the latest. thanks again


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