Hy A.L.D regarding the Beta 15 only will live in very big boxes 20 to 30 f3 modeling with WinISD 34 F3 will give a fabolous response in the 24 hz in a box . After more modeling I found that a box of 36 x 24 x 18 internal measurements with a port of 6 x 2.75 will give a very acceptable tunning frecuency of 34 hz but still a very big box but here the Beta 15 can breath much more . just do it