XLR question for bass

So, is your question about whether other balanced interconnects can improve your bass quality?   And what are you hearing that you don't like?  What improvement(s) are you seeking in the bass range?

Ah, I re-read and yes, there are plenty of interconnects that can tighten up the bass range.  I have no experience with your interconnects but I have found that gold and some copper can sound loose or excessive.  I'm using mostly silver wire in my system with plugs (RCA, XLR, and male & female AC) being either rhodium, platinum or palladium plated.  Compared to gold or copper counterparts I've used my system is more detailed top to bottom, with better control, and more precise image focus.  It might be to detailed and not as full-bodied as some would like but you can certainly improve the bass range with other balanced interconnects.  The Moon Audio Silver Dragon works nicely in my system and is relatively affordable.  Otherwise, I'm using DIY cables.

Connectors will NOT affect the sound in any way... unless you have absolutely crappy ones to start with.

Much more importantly, the Luxman has a "loudness" control. Use it :-).  It will make a great difference in the bass frequencies when listening at lower volumes. Look up "Fletcher & Munson curves" for extra explanation.

1. Moving the subs around will offer the best solution, assuming that there is no veto vote.
2. A DSP is another solution with or without #1
3. The isolators can work.
4. The XLRs are about the last thing that has a chance of being noticed.

So I would stop before #4, and not start with #4
#3 can be cheap and easy.
#1 is also cheap and easy.

Like ghdprentice said:

"Your best bet is speaker placement. Moving the speakers back and forth from the wall, and your listening position"

You may be sitting in a null point where the bass is cancelling out.  Have you tried moving your listening position?  In my room I have two listening spots.  The first is in the sweet spot - almost equilateral triangle.  Bass is good - tight, punchy and faster.  The second is about 4 feet further back at my drawing table.  Still sounds good but the bass is just a little overbearing on some tracks.  Actually works out pretty well because I usually sit at my drawing table at night and listen while I work.  The additional bass oomph works well at lower nighttime volumes.  Like a built in loudness button!

Pulling the speakers any farther out into the room might lean them out a bit more.  But it might change the bass nodes also.  You have to experiment with positioning first - both the speakers and your seat.  Or, maybe you've done that already?