As with all audio performance, assuming nothing is broken, 95% of the sound you hear is your speakers and your room.
Sibilance is in the 5-8000hz range which means it's in the tweeter.
Start by playing around with speaker placement, and also try changing where you are sitting. Moving a couple of inches can change things by 5-10db.
Next is to figure out what is going on with your room. Have you taken a thorough analysis of your room's acoustics? If not, time to look into room acoustics.
Alternatively, change your speakers back.
No cable change will fix your problem, (unless you have a broken cable)
Sibilance is in the 5-8000hz range which means it's in the tweeter.
Start by playing around with speaker placement, and also try changing where you are sitting. Moving a couple of inches can change things by 5-10db.
Next is to figure out what is going on with your room. Have you taken a thorough analysis of your room's acoustics? If not, time to look into room acoustics.
Alternatively, change your speakers back.
No cable change will fix your problem, (unless you have a broken cable)