I really thing it’s mostly due to atmospheric pressure and humidity levels in the house . Open the glass slider , leave it open , maybe it gets worse or better .
Maybe don’t shower and earwax is not as liquidated.
It’s not the equipment, it’s external variables .
And internal ones; hungry, in a mood, happy, tired, annoyed, drunk…
Stoned…
From Ask Paul (McGowan): Why do stereos systems sound different?
On a serious note, I’ve found that sometimes I just start to listen at too high a volume. That in turn lets the room interact with the music too much and for some reason dropping the volume from then onwards just feels like you’re missing a bit of power in the music. Starting to play at a lower volume has mostly given me more satisfaction.
Here is something very simple to try to see whether an allergen could be the culprit with sound quality changes. After taking a shower leave the water running and give your nose a good hard blow. If you hear the sound of the water in the shower get instantly clearer than you know there is something going on. In my case, the sound of the water almost always gets clearer which could provide an explanation as to why higher frequencies sound more muffled prior to clearing my nasal passages. Hope this helps!
Good idea.