From a minor recommendation standpoint, you should level match your two front subs so the combined output matches the output of the rear. For Audyssey's purpose, that would would be ~73dB. ;)\n\nBeyond that, I am surprised by the fact only the single Sub is being treated differently by Audyssey. I suspect there is a reason that may well have to do with the dual fronts on a single channel. Unfortunately, I am not certain what is causing it.\n\nConsidering you are possibly deep diving into the world of REW, it may be advisable to consider adding the MiniDSP 2x4 to the party.\nIt is an added expense, and up to you to decide whether to go for it. I think the HD version is generally the way to go, if you choose to.\nIn general, I wouldn't recommend this lightly, but without seeing more of your room, I have a feeling (just based on what I've read) that you need the help this will give in properly integrating all three subs.