Sibilance is usually evident in an ultra detailed tweeter. Cause is a usually a bright source. Many recordings (vinyl or CD) are not the best, which can excite the tweeter. Cables can tone things down a bit, but if it's really a problem you might look at your amp and or source. A chain of ultra revealing components can get harsh on all but the best of recordings. One or the other, or both, may be the issue. Or maybe the tweeter in the Nola is just not to your liking.
Did you have this issue with your previous speakers?
Did you have this issue with your previous speakers?