My treated room is small, 11 x 14. I have on REL S/510 with B&W 804s. The sub is invisible in my room. It’s tuned perfectly to integrate with my main speakers with Anthem’s Arc Genesis.
May I ask which connection method(s) you used for the REL S/510 along with your ARC-calibrated Anthem?
I just purchased a REL S/510 along with an Anthem MRX 1140 AV receiver, and I'm wondering if I really need to plug in the high-level connections as well as the LFE RCA. That is what REL recommends, however fishing that high-level cable through the walls/ceilings to the sub will not be possible for me, and as such I'm thinking of not using that connection and only using the LFE RCA.
My hope is that the Anthem MRX receiver + ARC calibration could (almost) just as well integrate the sub with the front left-right speakers by using the receiver's crossover settings and sending the bass signal through the RCA LFE connection, in effect having the sub support the front speakers and negating the need for the high-level connection. I would use the "Super Sub Fronts" setting on the Anthem MRX which sends the full range frequencies to the front speakers and duplicating the frequencies below the crossover by sending them to the sub.
I'm wondering what your experience is since you seem to have a similar setup to mine, at least with regards to the Anthem and sub!