ESSES suck… They’re all over the place on your vocals… They have to be audible to understand a vocal… but if you don’t control the sibilance, it can be distracting. A de-esser is a frequency dependent compressor- it only wordk on a certain frequency range… Understanding how to use one it an essential element of the mix process. First …know where they occur… male esses around 4.5k and above.. women 5.5k and above. There are lots of de-essers out there… and it’s easy to dial them in quickly. Now set the threshold just like on any compressor.. Determine when the deesser starts kicking in by adjusting while looping a section of audio... lower the threshold until it starts fixing the SSES, and preventing your from wincing while listening. Be CAREFUL… if you can hear the compressor working hard, you’ve gone too far. Don’t make the singer have a lisp… keep it sounding natural. Watch your meters too- take off a few DB, but it’s more important to listen. Some De-essers allow you to listen just to the affected signal to hear what you’re taking away. The de-esser should be last on your insert chain… always after any EQ boost because EQ affects how hard the De-esser has to work. On most de-essers you can choose the maximum amount of reduction, just like on a gate. Just like with other compressors, don’t kill your signal all at once…try stages of moderate de-essing… always on your source vocal track…. And then on your background vocal subgroups if you need more control. Mastering engineers use them too- and they’ll thank you for controlling SSES during the mix so they don’t have to work so hard. Now go slap on a DESSER for a SSSSSSSuper SSSSSLICK MIX.