If you email me then I can briefly describe how using the virtual room treatments from Machina Dynamica may be just what you need. Great WAF because can be hidden in plain sight, or barely noticeable when in position.
I have listened to before-and-after results of true speaker builder-modifiers, and the results working outside the cabinets with Machina Dynamica can be as effective, sometimes even better, than what is heard after a great deal of hard work by the builder-modifiers.
Certainly recommendable for those listeners who are all thumbs.
Additionally, inexpensive Big Fat Black Dots (speaker footers) from Herbiesaudiolab.com enable many speakers to sound their best.
Finally, after years of DIY speaker building, at least one experienced speaker builder I have encountered feels "the magic is in the cross-over".