What went wrong, 21" DP ported/4th order box Just made a new box for my 21" dp (the amp I will be running is a sundown 3500, I have (2) 1750 strapped right now, about 3000 watts) in a 2000 Ford Taurus. (8.3 cu ft/32hertz) The sub is facing up, with a top on it to direct wave more in the car and stop trunk rattle. The port is firing in the car. (I guess its sort of a 4th order/ported box combo) During the build I wanted to make sure since the port would be firing in the car and the sub facing up with a top on it, to completely seal the front wave from the rear trunk. After the installation, it was loud but noticeably louder with the trunk open. Ok I must have missed sealing something..... I noticed I missed a few spots and filled them with great stuff. At night in complete darkness i ran a light across the entire box to check for any leaks, (having light inside car while looking in from trunk) I also took the woofer out and check the entire box for leaks, maybe the top was leaking back in the trunk. Everything looked good. No leaks! Next morning I tested again, not only was the bass not as loud, but I also still had the same situation when opening the trunk??? I took all the great stuff off, open the back deck up now it loud as hell and no difference with the trunk open or closed????. Whats wrong here?
i think part of you problem is your making it more less a band pass by constricting the amount of air movment produced from the front of the sub. im not really sure thats just my best guess. NOTE- this is only if you leave your seat up
If you leave your seat down try sealing off the front of the box from the trunk like a wall but I seen crazy things like that on cars usually with to much sub in the trunk without being able to fold the seat down
