Yea, turn the OX point all the way down, 30-60. Set the gain to 12
Listen... Continue to raise the XO until you get the boom, then, lower it. until it goes away.
It’s a little to high, just like jjss49 said. Now to get a tad more punch, you could increase the gain, and you won’t get the boom...
Placement, to far from the mains with one Sub can be a little tricky. I would try center, forward (10-20") on the sub first. I push it back (away from the seated position) until the timing if off (muddy) then pull it towards your set until it blends MB to BASS. About an inch at a time. The low mids should be very clear. Phase shouldn’t be an issue with one bass unit, if you don’t get to far from the mains... A big room and a bookshelf can have issues to.. They can disappear to good sometimes..Best used in smaller rooms, and closer to the seated position..