This isn't a huge deal but I've found in the past with different guitar hardware simulators that if you overdrive a nice clean sound you get either/and a muddiness and a fizz.
This is also apparent in the Kemper but is fairly easy to fix unlike say, the Pod HD which could take me an hour to get the sound right.
It's a different problem than with a real amp somehow.
After playing electric guitar for 45 years I thought I may as well find out what others do to address this issue (if indeed it is an issue for other people)
Mike