I searched and google doesn't even know. So maybe someone has had some experience with this: I have only the stock Infinity system. The 6x9's are not blown out, but, in the bass low's I get an airy pitch instead of a solid punch. It's hard to explain in writing, but I can hear it more than feel it...if you get that. I don't know the exact freq, but I'm gonna guess and say its in the Hz range. Can anyone help?