Thanks for the response. The room null I am have right now is above the xo point anywhere around 90 to 120hz. Most likely is due the position of the speakers and the in room response. The node is at around 60hz so I have corrected most of the issue with a inline 12db/slope 70hz crossover for the speakers and the sub setting at around 50hz. Theoretically this would be a 6 db less at the xo point. On the contrary, the null that I have is probably more complex to fix. Honestly, this is a bad room dimension but it is the only room in the house I can relax.
As far as the position of the Hsu sub, yes it is in a near null position by not quite. That is why it is off centered to compensate the difference. I have the tools to do measurements so finding the best place for the sub is not a problem.