the tweeters on some speakers cause ear fatigue... and that is a tired-ness or slight discomfort in your ear drums from the tweeters...

if you have different speakers you can swap out with those.. try it for a few days with your set up... and see if you still get the same results.

my guess is that those tweeters are the cause of it.

good luck. it can really be a problem, that ear fatigue.