hi Paco and welcome. i have owned Thiel speakers since 1985 and have had four sets of the two series ending with the 2.7's. Now have the 3.7's. However for the past 20 years or so, regardless of speaker, i have been sitting in the same spot. you did not mention how far apart you have your speakers but i have mine about 3.5 feet from the back wall and they are roughly 9' apart from tweeter to tweeter, and about 7' from my ear. I believe in nearfield listening as it ameliorates a lot of the room issues. I still use room treatments but not a lot. Before you start trying all those room treatments, try moving into a different position as i think 9' is a long way to be from the speakers unless they are very far apart. Also make sure your ear is below the tweeter, not above. this is just a starting point for you. one suggestion: buy a spare mid/tweeter from Rob. Those drivers can be a bit touchy sometimes.