Fab explains what De-essers are and how to use them on vocals using 6 different plugins and hardware units.
De-essing is one of the biggest voodoo in the mixing world. Sometimes it works... and ssssssometimesssssss it does not. This is why you have so many plug-ins on the market that do just that. They all have different algorithms and work in their own special way.
This is why it helps to have a seasoned engineer show you how they work, show you pros and cons and most importantly point to you what to listen for during this risky exercise.