Using Dr. Griffin's white paper, I've been careful to watch the side of the speakers, their closeness, and the appropriate crossover frequency. Its not all that hard, even for a fella who has taken any math since 1965. Additionally, I'm of the belief that the critical mid range area of 300-3000 should remain as un bombed out by cross-overs as possible. This also figures into my "calculations".

My array crossed over to a sub woofer electronically at 24 db slope at about 80 hz.

What I appreciate with Dr. Griffin, is that he takes the time from his busy university schedule to explain things to non-technical people so we can build better speakers.
I enjoy this discussion, but I often wish that people would not autmatically assume that everyone here is an audio engineer.

thanks,

eric j.