Frequency Response Question

as far as i am concerned you should cut off at the -3db point or a bit higher. for those speakers 120hz-150hz is what i would try. but as always let your ears be your guide with your gear in your room.

What receiver do you have (and subwoofer for that matter), and does it have an auto calibration feature? If so, what does that feature want to pick?

Ideally your LF xover is above the -3 dB, to prevent dips in the system FR, but the room and placement will influence overall FR beyond what the anechoic numbers from Polk can tell us. In other words, the ideal crossover point may be different than what the specsheet would indicate.

With such small satellites, they're likely ideally crossed at some much higher frequency, but that may cause integration problems with the subwoofer.