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Sibilance by Waves is literally a DeEsser. Historically DeEssers are band compressors focused on frequencies between around 4kHz and 14khz, which is where problems with harsh sibilance in vocals usually are.
Because traditional DeEssers are really just band compressors, they can also be useful on other instruments or in mastering to tame harshness, this is NOT the case with Sibilance.
Waves’ Sibilance is specifically designed for harsh “S” and “Sh” sounds in vocal recording. The processing used to create “Sibilance” is something they call “Organic ReSynthesis”.
The manual states, “Organic ReSynthesis allows precise identification of unwanted S and Sh sounds, resulting in smooth, glitch-free, and effective DeEssing. Waves Sibilance reduces unwanted sounds flawlessly, while maintaining the timbre, duration, and natural resonance of the original sound.”
Followed by this IMPORTANT warning.
“Important: For superior results we recommend using Sibilance on single instruments or voices.”
If you view the demo embedded above you can hear Sibilance in action. It does it’s job well, actually DeEssing. You might not get what you want if you try to use it as you might use a standard DeEsser.
Sibilance is available https://www.waves.com/plugins/sibilance