Thanks for the replies everyone.

My take-aways are:

- Get a real sub (I bought my son a Hsu; he goes to college in a few months. It'll never fit in his dorm. Heh.
- I'm not hurting any of the Axioms with the 60 Hz crossover. but may be losing audio quality.
- I *can't* read a graph. (So that switch from Nuclear Engineering to Computer Science all those years ago was best for all concerned.)