I have the same system as you except with the Onk 818 and an EP600 v2. I don't have an external amp. I'm in a 4200 ft^3, under-damped room.
I listened to your track on Spotify with the highest SQ possible, PLII processing with panorama mode turned off. I had no problem hearing the train circling around my 7.1 system. In fact, I can also hear the circling in stereo but not as distinctly.
It's well known that continuous listening to pieces with heavy mid-range spectral content can be fatiguing. Maybe you are listening to music for longer periods now than before?
Having said that, there is a clarity, realism, transparency and presence to the upper mid-range on the v2 that unfortunately lends itself to sounding fatiguing at higher SPLs even when amplifier limits aren't being exceeded. Perhaps this was taken care of on the v4.
I was over at my buddy's last night listening to his KEFs. They were easy-sounding but at the expense of reduced transparency and "resolution". I find them good for movies but can't listen to music on them because it sounds like there's a veil over the sound source.
