The center is the Polk CS20, the sub is a 10" Lava and I have 4-TSI100s. The sound level meter is one of the things on my list, along with running the Audyssey. I have a Denon AVR591.
I just noticed an improvement when I went from 80Hz to 90 Hz to my untrained ears. I guess my question should have been more along the line of will these settings damage the TSI100s. This is a small system in an apartment, so I don't get close to reference. I am happy with the way it sounds now and look forward to check out the Audyssey Multi EQ.
I am not familiar with the free measurement software but will research that.