Thanks for the follow up. Hey, I remember the rope wave demonstration from school (was that middle school?).

I've seen posts on that calculation several time, but it didn't occur to me apply it like that. I guess I'll be measuring some distances this weekend! But given the configuration of the room, I'm not so sure I'm going to identify where that 2.25 ft (or 1.125 ft) difference is.

Might adjusting the toe-in of the speakers help, or is that barking up the wrong tree? (or would I just be shifting the null to another frequency)

The crossover is definitely set @ 80Hz so that's not the issue. I had noted that there are some anomolies on the graph around the crossover point, but that looked like an issue I could address after fixing the bigger issues!

Thanks so much for your assistance. This has been a great learning experience.

Rich