De-Essing

Definition

De-Essing (noun): In audio production, de-essing is the process of reducing or removing harsh sibilant sounds in spoken audio, which are often caused by the letter ‘s’ and similar consonants.

Detailed Explanation

De-essing is an important audio processing technique used to improve the clarity and listenability of spoken content, particularly in podcasting. Sibilance refers to the hissing sound produced by certain consonants, notably ‘s,’ ‘sh,’ ‘z,’ and ‘ch.’ These sounds can become overly pronounced, harsh, and distracting, especially when recorded with sensitive microphones or in less-than-optimal acoustic environments.

How De-Essing Works

1. Identification: The first step in de-essing is identifying the specific frequency range where sibilance occurs. This is typically between 4 and 10 kHz.
2. Detection: De-essers use detection mechanisms to pinpoint the instances of excessive sibilance in the audio track.
3. Reduction: Once identified, the de-esser reduces the volume of these sibilant sounds. This is often done using a dynamic processor that selectively compresses the frequency range where the sibilance is most pronounced.
4. Adjustment: The amount of reduction can be adjusted to ensure that the sibilance is reduced to an acceptable level without adversely affecting the overall vocal quality.

Types of De-Essers

• Broadband De-Essers: These reduce sibilance by applying compression to the entire audio signal when sibilance is detected. While effective, they can sometimes undesirably affect non-sibilant parts of the audio.
• Split-Band De-Essers: These apply compression only to the sibilant frequency range, leaving the rest of the audio unaffected. This type is more precise and often yields better results.

Practical Considerations

• Threshold Settings: Setting the correct threshold is crucial. Too high, and some sibilance may remain; too low, and normal speech patterns may be affected.
• Frequency Range: Identify the accurate frequency range for sibilance in your specific recording. This can vary based on the speaker’s voice and microphone characteristics.
• Balance: Ensure a balance where sibilance is controlled but the natural quality of the voice is maintained. Over-aggressive de-essing can make speech sound unnatural or lispy.
• Monitoring: Always monitor de-essed audio with good-quality headphones to accurately hear the changes made and fine-tune as needed.

Example

Imagine you are editing a podcast episode and notice that the host’s ‘s’ sounds are particularly sharp and piercing. Using a de-esser plugin in your Digital Audio Workstation (DAW), you first analyze the audio to determine the frequency range where the sibilance is most pronounced. You set the de-esser to target these frequencies and adjust the threshold and reduction settings to effectively minimize the harshness of the sibilant sounds without negatively impacting the overall clarity and naturalness of the host’s voice. The result is a smoother and more pleasant listening experience for your audience.

Benefits of De-Essing

• Improved Clarity: Reduces the harshness of sibilant sounds, making the spoken content clearer and easier to listen to.
• Professional Sound Quality: Contributes to a more polished and professional audio production.
• Listener Comfort: Enhances listener comfort by eliminating distracting high-frequency sounds that can be grating to the ears.