This is why I challenged you to test your audiblity skills in the last part because you may be able to hear how well they implemented the DSP processing and band limit filters by toggling ARC on and OFF with no EQ file uploaded. It isn't bad sounding but it does change the character of sound slightly. These minute differences happen with all AVR's and HT processors as it has to do with the nyquist theorm and dependency on the DAC, ADC and DSP circuits to apply correction. It makes it very difficult to compare a HT procesor or AVR to a 2 channel DAC or ADC that does signifigantly less processing. Much of this is not documented or shown in the measurements. While the measurements did appear to reflect a poor measurment perfomance, Anthem does have a good sounding implementation of their room correction and continues to improve upon it.
I finally did a randomized ABX test with my wife as subject. A was the input with ARC on but with no ARC settings uploaded and B was ARC off - both inputs were level matched. As there is no ARC settings, one would expect both inputs to sound the same. Out of eight tracks, she could correctly guess only twice if X was A or B. My son did the same test in parallel with also only three out of eight correct guesses (different ones than my wife though). In this setup (CD quality only, no high-res), I would say that ARC on/off are not really distinguishable by us - even though, I've still a feeling they sound differently... Maybe with a high-res source it would be different...