Looking For Speaker Help

My friend came to me with a 8" woofer, he wanted to step up from his stock system in his truck. I am in the midst of designing a basic 6th order box for his truck to go under or behind the seat. My problem came when i was working out the box diementions and realized i did not have the required volume the speaker needs. Through a couple hours of searching I have yet to come up with much and i was curious if any one knows what the required volume (in cu.ft.) for a Cerwin-Vega XL-8S 8" woofer would be, or where i can find an estimate. I was told that since it would be a ported enclosure ( this is if i couldnt find the correct volume) i could use a rough estimate round .5 cu.ft. , he said that should be close to what the specs might be.

                                                                                                                                                     Thanx for your help

                                                                                                                                                                        Corey

Well i would say .5 ft is more of a minimum volume for a sealed box.  More like .75 for a vented box with about an 8 1/2" port at 2" diameter.  Of course I could be wrong, this is just my guess based on my experience.

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