96 caprice bass cancellation

we have a 96 caprice we are working on and we are not transfering low bass into the cabin area, we have plenty of mid bass though. we have had several caprices lately come through not all have we installed, everyone we have heard is doing the same thing. our customer insited on 15's so here we go, turn the box every way you can in the trunk still the same thing, with the trunk open lots of bass with it shut no low bass. now from a long time ago i remember a rectangular box with a sub on each side in a impalla that i thought transfer bass pretty well, so i built one with four 15's and still the same results but we are hitting 140.8 at 70 hertz's, now i have been putting panels in to change standing waves in the trunk , anyone with any ideas please let me know, thanks ron.zargon ruler of estranorth

I agree with car tune man. My bother is ghetto & loves caprices. He has had 3 so far & always went with 3 12's sealed facing the trunk & they all hit hard. you might consider 3 15's instead of 4. 4 will take up the back section of the trunk & will seal off the bass from getting into the cabin.