Fpooyandeh, can you tell us a little bit about the room and speaker positioning? I know you have a "room correction" equalizer, but it cannot correct the loudspeaker's radiation pattern, and that might be part of the problem.
Bass varies enormously from one room to another, so while it's unusual for the Maxx to come up short in this department it's possible. Perhaps a change of speaker or listening position would be beneficial.
I would think the Accuphase would be well suited to driving the Wilsons within its power limits, but the Airtight might be a questionable match.
The component that has the greatest effect on your overall sound is the loudspeaker system. I hate to say it, but if you are looking to make a major change in how your system sounds that might end up being the component to replace.
If you are willing to consider a complete system change, the best sounding system I have heard was by Sonicweld. It's not cheap, but it includes everything except the source component(s). www.sonicweld.com. Don't let the appearance put you off - this system is about ultrahigh sound quality, not eye candy.
Best of luck to you,
Duke
dealer/manufacturer