I have 2 15" L7s in a sealed enclosure at about 8.5^3 and think it would sound better ported with the same air space. If it matters I have a hercules at .5ohms. Can someone do a diagram with the woofers firing toward the roof and port firing to the back? I would like it tuned to 34hz. Dimensions are 42x18Hx20D. Vehicle is a 98 Grand cherokee. Thanks in advance.