For some time now I have been thinking about making a isobaric sub. And I was wondering if any one else had tried this on a sonasub. I am looking for deep resonating bass. I have not decided on a driver yet. But I will be using the 16" diameter sonatube. I figure I will make 2 tops. One will be sealed and the other will be ported. I will then experiment with port lenghts versus sealed to determine which one will suit me best. The woodwork is not a problem I have a friend who is a cabnet maker. So what considerations should I think about for this project?