Ok, I see some who say don't put too much faith in the theoretical results of software when it comes to building a sub. I guess I don't understand. Been using UniBox for a while, and have come up with an AV15 in a 260L (net) box using a 19.52cm diameter port tuned to 17hz and 700W of power. At around 24hz the frequency response shows that the driver touches Xmax. I'm thinking this is ok because that is probably representing a sine wave signal which is not real world for home theater so less chance of actually bottoming the drive. Is this right? Also based on this same theory (not counting room gain) it will probably never reach calculated SPL?