I worked intensively for 3 months to dial them in. When I thought we reached that point the sub was virtually volumeless.
I assume you were trying to reach a bit deeper by adding a sub, but that the net result was a step backwards rather than a step forwards.
Obviously I've never heard your system nor been to your room, and even if I had I wouldn't begin to know them as well as you, so this will be sheer speculation on my part.
Long long ago, in a galaxy far far away, speaker designers tried to bring balance to the force by perceptually matching the top-end extension to the bottom-end extension. So if a speaker went down to 25 Hz, it should go up to 20 kHz (if I recall correctly... this was, after all, long long ago). But if a speaker only went down to 50 Hz, then it should only go up to 10 kHz, so that it would still sound balanced.
Then along came the Spec Wars and greater top end extension equaled more sales. So speaker designers invented the Upper Bass Hump, which kinda sorta restored balance to the force.
Fast-forward to Steve's room and system, by all ears-on accounts a masterpiece within a masterpiece, wherein balance has been created... such that adding a sub loud enough to be audible degrades this precious balance, which (according to the ancient wisdom) matters more than any improvements in low-end extension.
So, here's a radical possible solution: Add a bit more top-end energy to restore balance by perceptually matching the additional bottom-end extension of the sub. But do this with a rear-firing or up-firing tweeter, not a forward-firing one, because we don't want to do anything that would mess with the first-arrival sound. The specifics matter and I won't get into them here and now, just tossing this out as a highly unorthodox idea... whose roots arguably trace back to a time long long ago...
Imo this proposal is not entirely theoretical. I have used rear-firing tweeters when adding subwoofers to balanced-on-their-own fullrange driver speakers, such that once everything was dialed in, balance had been restored but with nearly two octaves added to the bottom end.
It took George Lucas and friends six episodes, some of them epically cring-worthy, to restore balance to the force, and I'm not sure they ever really did. So this may not be as simple as I have made it out to be. And I understand that the subwoofer ship has already sailed from Steve's room, so this is all just hypothetical anyway... unless it has only sailed fifteen or twenty feet down the hall, into the next room...