What Is A De-Esser and How Does It Work?
In this article, I aim to demystify the de-esser and help explain how to use one in your mixes.
Example of a de-esser plugin. Waves Renaissance DeEsser displayed.
What is de-essing?
De-essing is a technique intended to reduce or eliminate excessive sibilance around consonants such as “s”, “z”, “ch”, “j” “ts” and “sh” within recordings of the human voice.
What is a de-esser?
A de-esser is a specific tool that audio engineers use to reduce sibilance within a recording. Specifically, a de-esser is a form of multiband compression, where a sibilant frequency range (usually between 2-10khz) of a source is isolated and compressed every time it becomes too overpowering in a mix.
What parameters are commonly found on a de-esser?
Most de-essers commonly have a few parameters, as defined below:
Threshold – Correlates to the volume of the material and is the point at which the de-esser begins to work. Once your signal exceeds the threshold, the de-esser kicks in to reduce the volume
Range – Limits the amount of gain reduction that can take place on the sibilant parts. If a de-esser is set to reduce the sibilance by 10db, but the range is set to 3db, the most gain reduction that will take place on the track is 3db as that is the maximum range of the de-esser.
Release –Determines how soon the compressor stops working once the signal dips below the threshold. In other words, how soon the de-esser plugin will “let go” of the signal after compressing it.
Frequency – This usually spans over a range of frequencies and helps control exactly what ones will be reduced during the sibilant moments of the track.
FabFilter Pro DS – another example of a popular deessing plugin
Should I De-Ess Before or After Compression?
There is no definitive answer to this question as mixing, like creating music itself, is subjective. From my vantage point, it is situational and depends on 3 main factors:
1) The state of the source material – how does it sound naturally?
2) What processing is being applied to it? (EQ, Compression, etc)
3) How does the processing affect the source material and it’s sibilance?
Based on your answer to the above in sequence, you can effectively prioritize where to place your de-esser.
It can be very effective to de-ess early in the chain before compression as compression can often bring out sibilance in a track. By reducing it beforehand, when applying compression and other processing, the sibilance should not stand out as much or create problems.
However, sometimes that is not the case and de-essing can suck the life out of a recording by taming the high-end too much. In such a situation, de-essing after compression may work best. Compress the source material first to even out the dynamics, including the sibilance, and if it still stands out too much, apply a de-esser afterwards to reduce those specific harsh frequencies.
Another strategy is to use multiple de-essers in series (back-to-back) in order to reduce the sibilant frequencies more moderately and in stages, which will lead to a cleaner and more transparent sound.
Should I De-Ess Before or After EQ?
Similar to the last question, the answer is situational.
Often I will de-ess at the start of my mixing process if sibilance is an immediate issue and dress the vocal from there. I frequently incorporate a shelf EQ to boost the high-end later in my vocal chain. With problematic vocals, boosting the high-end often increases the presence of sibilance, and can lead to harsh resonances that are painful to hear.
In such a situation, de-essing after EQ may prove to be more helpful in preserving the high-shelf EQ boost, while reducing specific problematic frequencies within the sibilant frequency range when they occur as a result of the EQ.
The Best Form of De-Essing
In my opinion, de-essing is best done manually with strategic volume and clip gain automation first since using an actual de-esser can come off as aggressive and noticeably change the sound of the source material. Focusing on manually adjusting the sibilance within a mix will put you in a position to transparently tame the harshness in your mix, and contribute to a better end product overall.
Once you’ve implemented manual de-essing into your mix, you can explore additional treatment options such as using a de-esser if it is still needed.
Alternative Use Cases
While a de-esser is a great tool for treating sibilance in vocals, they are incredibly effective at processing specific frequency ranges for in other sources. A common alternative way that I use a de-esser, is I will put it on metallic hihats and cymbals to tame brightness, or on a guitar-style sound to tame specific harsh frequencies. I’ve heard of people also using a de-esser to compress the boxy frequency of a kick drum in order to help it sit better in the mix. Just because its called a de-esser doesn’t mean it has to be used specifically for treating sibilance. Its an all-around useful tool when applied correctly.
More Learning
Get a better understanding of how to use a de-esser in your mix by booking a Mixing & Mastering Lesson with 5PiECE.