What is Sibilance?
Also called: esses
Sibilance is the hissing energy of consonants like s, sh, z and ch in a vocal. When it is too strong, those sounds become sharp and piercing and draw attention away from the words.
Sibilance sits in the upper frequencies, typically somewhere between about 4 and 10 kHz depending on the voice and the microphone. Bright microphones, heavy compression and high EQ boosts all make it more pronounced.
The usual tool is a de-esser, a compressor that only reacts to that frequency band, so it turns down the harsh consonants without dulling the rest of the vocal. Small manual volume dips on individual words also work well.
Removing too much sibilance makes a singer sound like they have a lisp and can make lyrics harder to understand, so the goal is control, not removal.
Put it to work
Analyze how clear and intelligible your vocal is, including harsh consonants.
Analyze Vocal Clarity