Do you have an artist who's S's or Esses are really pronounced? Everytime the artist has an S in his or her sylibols there is a very pronounced S that occours occasionally. At Elmwood Audio we use Logicc Pro X as a D.A.W. and there is most defineitly a De-Esser plug in stock, but sometimes that isnt enough. Also cutting it out with EQ will effect the singers dynamic. Rubberbanding a pencil (yes rubberbanding a pencil) to the microphone is the best way to deal with this problem! Of course you want to couple that with a pop filter (or two).
Make sure the pencil is sitting stright up and in front of the diaphram. This breaks up the air and sound pressure hitting the diaphram that creates the undesired Esses. Try it! If this helps I would actually love to hear about it, send me a message. I used this technique to help my friend Katie, whos album is currently in production here. It worked wonders! But you do have to check up and make sure the pencil is still sitting where it needs to be.
I'm busy working on my blog posts. Watch this space!