[Mike P.]

Your graphs look good, they are comparable to what I've modelled for those 2 subs. As for the Infinity Kappa Perfect 12 sub, it models very close to the Adire Shiva Mark 3, which I have 2 in sonotubes. They have excellent output down to 20hz and lack in output below that. For sub-20 hz output you really need a long throw 15 inch or bigger subwoofer. An example would be the last graph you posted. There is a 10 db difference between the Kappa and Tempest-X at 18 hz.