2 Fi sp4 18 box help

[onebadmutt]

Building a box for my boss with 2 sp4 18's. The box 16.49cft. He wants a square port tuned to 30hz, and I can't come up with an efficient port with enough volume and keep it at 30hz. Any help would be awesome. Pulling my hair out. Math overload.

Thanks

[Joe X]

You better get that box right! LOL, you should post vehicle, max dims fo a box amp, electrical and else to get some help.