Wilson Alexia 20x15 Room

Audioconnection,
That's an interesting observation and implies you're familiar with this system.If better quality cables resolve this problem it's certainly cheaper than replacing the speakers. Or perhaps the OP just simply wants new speakers.

The OP has been very clear, he wants big sound.

Well it seems according to JohnnyR big sound is possible with his suggested speaker cables.

Furthermore OP has absorption everywhere front wall,side walls and absorption at rear walls behind listening chair.

It should be Diffusion at least w/side walls for best performance or nothing is even better that absorption.

Test by removing all absorption front side and back remove out of the room insert AQ DBW and listen,and see how you like it.
Replacing absorption with diffusion will get the joy and magic back in the system.
With too much Absorption we are killing the music's leading edge attack,overtones,harmonics even/perception on Height.
This is why OP also found that band aiding the system with a ringy wire kinda helped.
Try the experiment of Absorption removal and In-cert AQ
add Diffusion
Best JohnnyR

Yes,
Excessive room absorption takes the life and natural vibrancy of music away. The resulting sound is dead and uninvolving.I'd give JohnnyR's suggestion a shot.