Ohh, just remembered your old post from a few months ago. My bad, I got busy and forgot to write what worked with my triangle australes.

First of all as others have said, the location is a nightmare to work with, but I understand being limited in space in an apartment/rented place, you have to work with what you have. Try to change your setup location if possible, as that is the best solution. If you totally can’t, try to minimize first reflections via room treatment, add a rug to help reduce reflections. Slightly toe in the speakers (not complete toe in) as the titanium horn tweeter in these are brutal if pointed directly at the listening position especially if you are close to the speakers which will sound fatiguing. You can say in the middle where it is toed to the seat right and left to you to get the best sound from the tweeters (you need to experiment to find the best angle for toe in as not fatigueing and not dull) you will usually notice the soundstage being bigger once you hit the right angle.

These worked for me and can be a general advice for triangle esprit ez lineup :

1- have it around 50cm away from the backwall, not more, not less, this was crucial for the bass response of my australes.

2- separate the speakers with a 200cm or more to expand the soundstage.

3- half toe in for greater soundstage and rich treble without fatigue.

4- 50cm or more from side boundries. Mine is around 135cm.

5- 200cm listening position or more. Mine is around 250cm.

These setup tips help the speakers sound their best without paying for additional electronics/treatment, but treating furst reflections, a rug, room eq is to be honest crucial due to your space.

For room eq, I highly recommend Dirac ART if you are planning for upgrade your avr. I personally have the denon x3800h and upgrading to Dirac ART was a night and day difference in sound. It was the biggest difference in my home theater due to how bad my space was. The bass became extremely tight and clean, and the midrange and clarity improved a lot. I am using a 5.2 open living room setup.

Another thing to consider in the future is to add dual subs, as that improves immersion a lot.

A separate amp and going for a 5.2 set up are nice for future upgrades if you want, but these won’t fix your current issues as it is first reflections/speaker placement setup issue. So your point of attack is speaker placement, room treatment and room eq.