1.5cft box =what in litres?

i have a 27h focal going into it what will be my port [img]graemlins/dunno.gif[/img]

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-
400 W
200 W
94 dB
35 Hz * - 1,5 kHz
* Depend on load
46,6 Hz
3,1 ohms
0,53
8,47
0,50
21 cm
64,7 g
0,7 mH
20 mm
8 mm
6 mm
346,4 cm2
30,4 l
10,5 N/A
233 mm
117,5 mm
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25 - 40 litres
i'm running a pg 500.2 to it

 

so if i do 2x 3"x 4 1/16" ports willi get 35 herts
is this right
did i do i ok

 

http://www.sciencemadesimple.com/conversions.html