What is De-essing? How to Clean Up Your Vocals

What is De-essing?

De-essing, as the name suggests, is a process used to reduce or eliminate excessive sibilance ('ess' sounds) in vocal recordings. Sibilance usually presents as high frequency sounds often found in vocals when words with 's', 'sh', 'z', or 'ch' sounds are pronounced. These sounds can become overly prominent and harsh in a recorded track, and that's where de-essing becomes invaluable.

In technical terms, a de-esser is a specialized type of compressor that acts predominantly on a specific frequency range. It's often described as a frequency-specific compressor because it only compresses the signal when certain frequencies - typically those associated with sibilance - exceed a particular threshold.

So, how does a de-esser work? When you apply de-essing, the tool essentially "listens" to the frequency spectrum of the audio signal. When it detects excessive sibilance, it momentarily reduces the level of those frequencies. It does this by compressing the signal, much like a standard audio compressor, but only for those specific problematic frequencies, and only when the level of those frequencies exceeds a certain threshold.

However, it's not as simple as just applying a de-esser and being done with it. De-essing requires careful calibration to be effective. Set the threshold too low, and the de-esser might cut out too much of the high frequencies, making the vocals sound muffled or dull. Set it too high, and it might not catch all instances of sibilance, leaving the harshness intact. Similarly, choosing which frequencies to act upon requires careful listening and adjustment. Too broad a frequency range, and you might affect parts of the signal that don't need de-essing. Too narrow, and you might miss certain instances of sibilance.

Overall, de-essing is a powerful tool in the arsenal of audio production techniques, helping to polish and refine vocal tracks. With careful use, it can significantly enhance the clarity and quality of your recordings, making for a more pleasant and professional listening experience.

How De-essing Works

A de-esser is a specialized form of a compressor that focuses on controlling the excessive sibilance or 'ess' sounds in vocals. But how exactly does it do that? It does so by isolating and compressing only the specific frequency range where the sibilance occurs.

Here's a more detailed step-by-step process:

Identify the Sibilant Frequencies: The first step in de-essing involves identifying the frequencies where sibilance is most prominent. Sibilant sounds usually occur in the higher frequency range, often between 5kHz and 10kHz. However, the exact frequency can vary depending on the specific voice and microphone used for recording.
Set the De-esser to the Target Frequencies: Once you've identified the problematic frequencies, you need to set your de-esser to target these. Most de-essers will have controls allowing you to select the specific range you want to focus on.
Detect and Compress: With the target frequencies set, the de-esser 'listens' to the signal and detects whenever the level in those frequencies exceeds a certain threshold. This threshold is adjustable, allowing you to decide how sensitive the de-esser is to sibilance. Whenever this threshold is exceeded, the de-esser kicks in and compresses the signal, reducing the level of the sibilant frequencies.
Adjust to Taste: From here, you can fine-tune the settings of the de-esser to achieve the desired results. You might adjust the threshold, the range of frequencies targeted, and the amount of reduction applied. Many de-essers also offer different modes of operation, such as wide-band and split-band de-essing, each with their own benefits and considerations.

It's worth noting that de-essing is not a 'set and forget' process. It requires careful listening and adjustment to ensure that it's effectively reducing sibilance without negatively impacting the overall quality of the vocals. Overuse of de-essing can result in vocals that sound dull or lackluster, so it's always a good idea to use this tool judiciously and in conjunction with other mixing techniques.

In essence, de-essing works by selectively compressing sibilant frequencies, helping to control and reduce harsh 'ess' sounds in vocal recordings. When used properly, it's a powerful tool that can greatly improve the clarity and quality of your mixes.

Software and Tools for De-essing

There are a wide variety of tools available for de-essing, ranging from simple, one-knob plugins to more advanced, multi-feature tools. These include both standalone de-esser plugins and broader audio editing software with built-in de-essing capabilities.

Did you know Synchro Arts offer de-essing capabilities in Revoice Pro and RePitch Standard? This is achieved through our advanced pitch analysis technology which detects ‘unvoiced’ notes – the sibilance that naturally comes from vocals. All you need to do is lower the dB of the unvoiced notes to clean your vocals. Watch it in action below:

When and Why You Should Use a De-esser

A de-esser is a specialized audio tool that plays a vital role in the post-production process of audio mixing, particularly in managing vocal tracks. Knowing when to apply it and understanding its significance can greatly enhance the quality of your mix.

When to Use a De-esser

The primary indication to use a de-esser is the presence of noticeable and distracting sibilance in your vocal tracks. If you hear an excessive 'ess' or 'sh' sound that seems to pierce through the mix during playback, that's a clear sign that de-essing may be necessary.

It's also worth noting that certain microphones tend to exaggerate sibilant frequencies, so if you're working with a particularly bright or sibilance-prone mic, you might find yourself needing a de-esser more often. The same applies to certain voices - some people naturally have more sibilance in their speech or singing than others.

Finally, the genre and style of the music can also play a role in determining when to use a de-esser. Vocal-heavy genres, or genres that favor a bright, clear vocal tone, often benefit from careful de-essing.

Why Use a De-esser

The main reason to use a de-esser is to enhance the quality of your vocal tracks and, by extension, the overall mix. Excessive sibilance can be distracting and unpleasant to listen to, and can make a mix sound amateurish if not properly controlled. By reducing these harsh, high-frequency sounds, a de-esser helps to smooth out the vocals and make them sit better in the mix.

In addition, effective de-essing can help prevent issues later in the signal chain. For example, sibilant sounds can trigger undue compression or limiting if you're using these tools on your master bus, leading to an unbalanced and potentially distorted mix.

In essence, using a de-esser when necessary is an integral part of achieving a professional-sounding mix. It can help to provide a more balanced, pleasant, and polished final product.

How to Use a De-esser Effectively

While the concept of a de-esser is relatively straightforward, using one effectively requires a good ear, a clear understanding of the issue you're trying to fix, and a careful approach. Here are some guidelines:

Identify the problematic frequencies: Before anything else, you need to know where the sibilance is happening. The specific frequencies can vary depending on the voice and microphone, but sibilance usually occurs somewhere between 5kHz and 10kHz. Listen to the vocal track carefully, and try to pinpoint where the 'ess' or 'sh' sounds are most prominent.
Set the threshold and frequency range: Once you know where the sibilance is occurring, set your de-esser to focus on those frequencies. The threshold control determines how sensitive the de-esser is - if the signal within the targeted frequency range exceeds this level, the de-esser will start to compress it. If you set the threshold too low, the de-esser may act too aggressively and make the vocals sound dull or muffled. If the threshold is too high, it might not catch all the sibilance. You'll need to adjust this carefully.
Adjust the amount of reduction: Most de-essers allow you to control how much the signal is reduced when sibilance is detected. Again, this needs to be balanced - too much reduction can lead to unnatural-sounding vocals, while too little might not adequately address the problem.
Listen in context: Always remember to listen to your adjustments in the context of the full mix, not just in isolation. The aim is to have the vocals sit nicely in the mix, and sometimes what sounds like too much sibilance on its own might not be an issue when the vocals are played with the rest of the track.
Avoid over-de-essing: Over-de-essing can make the vocals sound dull and can cause 'lisping' artifacts, where the 's' sounds are overly suppressed. If you find that you're needing to apply heavy de-essing, it might be worth looking at other elements of your mix - perhaps something else is making the sibilance more noticeable, or maybe the recording could be improved.
Use multiple de-essers if needed: Sometimes, you might find that there's sibilance happening at multiple frequencies, or that a particularly problematic 'ess' sound still sneaks through after the first round of de-essing. In this case, it's perfectly acceptable to use more than one de-esser, each one focusing on a different part of the frequency spectrum or a different aspect of the problem.

Using a de-esser effectively is a vital part of professional vocal mixing. By taking a careful and measured approach, you can smooth out your vocal tracks and help them shine in the mix.

Common De-essing Mistakes and How to Avoid Them

Over-de-essing: Perhaps the most common mistake is applying too much de-essing. When overdone, it can cause the vocals to lose their brightness and clarity, leading to a dull, muffled sound. It can also introduce lisping artifacts, which sound unnatural and distracting. To avoid this, use de-essing sparingly and always listen in context with the rest of the mix. Start with subtle settings and only increase the intensity of the de-essing if necessary.

De-essing in Isolation: De-essing should always be performed in the context of the full mix, not just in isolation. What might sound like excessive sibilance on a solo vocal track could be perfectly fine when the track is played with the rest of the mix. Always remember to check your de-essing adjustments with the full mix playing to ensure they're necessary and effective.

Ignoring the Recording Phase: Remember that de-essing is a remedial process—it's there to fix problems that couldn't be avoided during recording. If you find yourself consistently needing heavy de-essing, consider revisiting your recording setup. The choice of microphone, the microphone placement, and even the singer's technique can all impact the amount of sibilance captured in a recording.

Choosing the Wrong Frequencies: De-essers need to be correctly set to target the frequencies where sibilance is occurring. If these are set incorrectly, the de-esser might not do anything (if the frequencies are set too high) or it might affect the wrong parts of the signal (if they're set too low). Listen carefully to identify where the sibilance is happening and set your de-esser accordingly.

Using a Single De-esser to Solve All Issues: Sometimes, a single de-esser might not be enough to effectively control sibilance, especially if it's occurring at multiple frequency ranges. Don't be afraid to use multiple de-essers if needed, each one focusing on a different part of the frequency spectrum.

Setting and Forgetting: Like many audio processing tools, a de-esser isn't something you can simply set and forget. It requires careful adjustment and constant monitoring to ensure it's doing its job without negatively impacting the overall sound. Always revisit your de-esser settings as the mix progresses to make sure they're still appropriate.

By being aware of these common pitfalls and understanding how to avoid them, you can use de-essing effectively to enhance your vocal tracks and achieve a cleaner, more professional mix.

Conclusion

De-essing is an essential part of vocal production, providing a remedy for harsh sibilance that can distract from the listening experience. While it requires a careful approach and attention to detail, effective de-essing can significantly enhance the quality of your vocal tracks. Don't shy away from experimenting with different de-essing tools and techniques until you find what works best for your unique sound.