You are probably right about the 30 ohm resistor, but thats what I have been using in other non variable piezo x-os, and its just about right.Also, as asked further down, have you ever used the Eminence Gamma 12 in a PA box, I had great trouble getting a sensible box size, ended going fully sealed and fully stuff about 95 litres, hope it works. If it doesn't, I'll swap it out with a beta 12 and port that section of the box.