Maybe I didn't notice it because around 60 hz is where most of the punch is at. Above that its more of a buzz instead of a rumble and I don't enjoy my sub playing that anyways.
I guess its a preference thing, but I hate the way my sub sounds crossed at 80hz compared to 63hz where I have it set now with a steep slope. It still does what its supposed to do, hit the lows and punch like a mother...