It's amazing what just a few inches will do! I had my left speaker 2 feet from my left wall (wall to the edge of the speaker). Clayton has an owners' manual now and he advocates no less than 18 inches from the sidewall to the edge of the speaker. So I tried it. Back and forth between 24 inches and 18 inches. Of course, I had to keep shifting the right speaker so it was symmetrical. I played large orchestral music (using the stereo, 2.0, channel versions). At 24 inches, the center sounded congested. At 18 inches, the center sounded thin. After about three moves, I decided, 'what the heck' and split the difference to 21 inches. Whoa! Huge difference. The center sounds wonderful and the full orchestra, choir, and soloists are all spread out behind the speakers correctly. Today, with the speakers still at the 21 inch mark, I played a variety of music and again, it all sounds wonderful. Remember, my speakers are 5 feet from the front wall.
Also today, I played a jazz track I know very well. Deep bass, piano and drums. I was interested in decay, smearing, and boominess. All three instruments were crisp and sounded great. No issues that I could hear. I do have room treatments, which I am sure helped. The album is "McCoy Tyner with Stanley Clarke & Al Foster." I have the SACD 2.0 version. Original release date is 2,000. Stream it. The specific track that will "rock" you and your system is the last track: "I Want to Tell You 'Bout That". There are two versions of the same track. I like the last one the best.
I am sooooo enjoying the X3s.
Marcus