^ Based on your Measured results, your room appears to be eating frequencies (room Cancellation Dip) between 100 and 200Hz. This is probably why ARC has chosen such a low Room Gain value. (Typical values would be 2-4dB for Room Gain.)
It also means that your Center measures as having a Resonance Peak around 100 Hz -- i.e., as it comes sharply out of that dip. This is probably why ARC set its Crossover that high -- to help eliminate that excess energy. This is by no means ideal, as a Center Crossover above around 100Hz starts steering noticeable amounts of male dialog into the Subwoofer, which is not a good thing.
I suggest you use the Quick Measure feature in Tools -- shows realtime results for one speaker at one mic location -- and see if repositioning the speakers a bit further away from walls and corners helps smooth out the results between, say, 80 and 200 Hz. If your speakers have any adjustments for bass or low mid-range output (ports, for example, that can be open/closed, or response curve settings), check that these are set appropriately -- typically meaning to do nothing and let the speaker produce what it produces naturally.)
You can't specify the "Crossover" for the Sub. ARC needs the freedom to pick a Sub Crossover that works best with the Crossover frequency(s) selected for the other speakers.
You CAN specify the Cutoff for the Sub -- which is like a "MAX EQ" setting for the Subwoofer in that it tells ARC how far up in bass frequencies to assign correction resources to the Sub output. It is not unusual for your choice of Sub Cutoff, and the upload value for Sub Crossover to be different. A higher Cutoff than Crossover is still meaningful in terms of reproduction of the LFE channel (the .1 of 5.1 or 7.1), which can go up to about 120Hz although the bulk of its energy is usually between 50 and 80Hz. I.e., if ARC is allowed to correct the Sub higher in bass, then you get better results from the high frequency end of the LFE channel. But if doing that screws up the rest of the Sub correction then you are assigning to many correction resources up there and need to be more conservative.
Keep in mind that these things roll into effect over about one octave (factor of 2 in frequency). So for example if you set a Cutoff of 80Hz for the fronts, that means you should be looking for a good fit in the result (match of Calculated curve to Targets curve) down to 1/2 that, or 40Hz. I.e., the fronts should be able to produce quality output (after correction) down to 40Hz because that range from 80 to 40Hz is where they'll be sharing output responsibilities with the portion of bass that's steered to the Sub.
Often ARC will pick a higher Cutoff for a main speaker because it discovers it can't correct that speaker well all the way down to 1/2 some lower frequency. But in the case of your Center speaker, I think it has picked 110Hz because it is trying to use Crossover as another tool to tame that Resonance Peak at 100Hz.
Last edited by Bob Pariseau; 09-01-2017 at 12:57 PM.