So how this all ended up? I just received my 21SW152-4, and plan is to pair it with my two cubo18 loaded with RCF L18P400. Mostly for listening all kind of music at home but now and then weddings and other partys a bit louder. All I want that the 21" would do, is going ~35hz to down low as down as possible. There is that one drawing, but with slotted port calculator its tuned way too high? Or am I missing something? Wanna try something simple with one port this time tho.