Sibilance

To address sibilance on a DiGiCo Sx1, once can use a dynamic EQ:

DiGiCo's S31 dynamic EQ: Here, the green band has the dynamic EQ turned on; here, around 5 kHz, the volume is currently being lowered. For the purpose of de-essing, the mode (top right) must be set to 'Over' so that when the level at 5 kHz exceeds the threshold, then the level of the 5 kHz band is reduced.

Steps to follow:

• Touch the "Show dyn EQ" button, and then switch one of the EQs to a dyanmic EQ
• The EQ must be in "Over mode", i.e. arrow on threshold pointing to right, i.e. when level is higher than threshold, the dynamic EQ has an effect
• Compression ratio of 2:1 to 3:1 has enough of an effect without influencing the sound too much
• The compressor must typically be quite fast, i.e. short times, to sound as natural as possible
• Centre frequency typically in the range 3 to 7 kHz
• Gain of compressor should be –10 to –20 dB
• Q typically 1 or higher

What exactly is sibilance?

Sometimes a vocal can sound very irritating—listen to 10 s of this (start at 4:01):

That “S” sound at the end of a word is called “sibilance”. It occurs typically in the 4 to 8 kHz range; that same range is needed to get clarity and presence in a vocal. Too much, almost like symbols, very quickly becomes very irritating. However, too little, and a person battle to hear what is being said.

From the clip: This is the 'wy' of 'wys' in 'Wil ek vir jou wys wat leer...': the frequencies shown at the bottom correspond to the yellow cursor at the top.

This is the 's' of 'wys' in 'Wil ek vir jou wys wat leer...'—note the portion that is significantly louder. The 5 kHz peaks at –50 dB, which was previously –63 dB—that’s a 13 dB difference, which represents more than four times the volume (6 dB is a doubling).

The process of removing sibiliance is called “de-essing” or “desibilising” (https://en.wikipedia.org/wiki/De-essing).

The first step in the process of improving sound is normally recording better quality sound at the sound, thus placing the microphone further away (which Marthinus already does), and aiming the microphone higher or lower (away from the mouth), as you can see in, for e.g. https://www.soundonsound.com/techniques/managing-sibilance or https://urm.academy/death-to-sibilance/.

If one already has the sound, you can process it via an EQ. The challenge with this is that taking away too much of the “s” sound results in losing clarity and presence. Thus one wants to only take away the problematic portions when they are excessive, but leave them the rest of the time, i.e. compress that which annoys, but only when necessary.

Reaper’s built-in 'De-esser'

Reaper’s “De-esser” is a single-band dynamic EQ.