# What is sibilance?

The harsh, hissing edge on S, SH and T sounds. It sits around 5–8 kHz, and once you notice it in a pair of headphones it is hard to stop noticing — it makes a voice tiring to listen to long before it sounds obviously wrong.

![A frequency chart of a voice with the 5 to 8 kilohertz band highlighted, showing the sibilant peak that a de-esser reduces while leaving the rest of the voice alone.](https://mubert.com/tools/cast/docs-media/diagrams/what-is-sibilance.svg)

Sibilance is not a mistake you made; it is the shape of your voice meeting the shape of your microphone. Bright condenser mics and close positioning both push it, and any EQ that adds "air" or "presence" pushes it further.

It gets worse after processing. Noise removal and enhancement lift high frequencies along with everything else, so a recording that was merely crisp can come back spiky.

A de-esser is the tool for it: a compressor that only reacts to that narrow band, so the S is tamed and the rest of the voice is untouched. Cast has one in the lane's Track effects, and it has an intensity control precisely because the right amount is a matter of taste.

**Tame harsh S sounds:** The de-esser sits in the lane's Track effects with an intensity control, so you decide how much of the edge comes off. https://mubert.com/tools/cast/upload

## Related

- [What is a de-esser, and what is sibilance?](https://mubert.com/tools/cast/docs/what-is-de-esser)
- [What is a plosive?](https://mubert.com/tools/cast/docs/what-is-plosive)
- [The AI cleanup made my voice sound robotic — how do I fix it?](https://mubert.com/tools/cast/docs/sounds-robotic)

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Source: https://mubert.com/tools/cast/docs/what-is-sibilance · Cast docs
Last updated: 2026-09-14