VO Studio Acoustics: Seeking Sibilance Solutions

Every voice actor encounters sibilance somewhere in their recording career. Solving sibilance in the VO studio and dealing with harsh “S” sounds can be a tricky proposition. Here are some practical approaches to solving the sizzle.

There’s nothing as annoying as hearing a glorious performance interrupted by bursts of static-like sibilance every time we form an “S” sound. I’ve spoken about solving sibilance before, but it’s really a slippery subject. Ok, sorry, I’ll desist with the sounds of essing…

Sibilance is an overwhelmingly hissy or sizzling “S” sound in your recordings.

As a listener, it can be very off-putting. Sibilance can also be intensified by various dynamic effects such as Compression or Limiting, so it’s a good practice to pay attention to the results at the end of your processing chain, even if your raw audio sounds clean.

Dealing with the Sibilance: Step 1 – Identify the sound

First, you have to hear it clearly to begin with. Sometimes we don’t. Those upper frequencies where the harshest parts of sibilance live are also where most hearing loss begins to occur. If you aren’t hearing those higher registers as well as you used to, having a second set of ears (not literally – I mean sending things to a trusted VO partner), or getting better at understanding Spectral Rendering of your audio can be a valuable backup.

If you don’t have either of those, using a Frequency Analyzer (such as Blue Cat’s Frequency Analyzer or the SIR Spectrum Analyzer) can also help to identify sibilance buildup (as well as expose the lower frequency rumble I wrote about last week).

As with any acoustic issue in our voiceover recording studios, solving sibilance is a challenge best addressed at the source.

Solving Sibilance Starts With Us

When solving sibilance in the studio, there’s a cold truth: some of us are simply more sibilant prone than others. Curiously, those who speak with a bit more precision can find it to be a problem. If you draw your lips and jaw tightly when forming that sound, it tends to produce more sibilance. Also, the more you form the sound by pressing your tongue towards the inside of the front teeth, the sharper the “S” becomes. The converse of this is totally relaxing the jaw and lips, and forcing the tongue down when you create the phoneme. It will sound awful, by the way, but going too far will let you understand the biomechanics.

Aren’t sure if you have sibilance? Try recording this sentence:
“Seven silly simians silently sipped sassafras teas”

Even a slight softening at the source can be beneficial in solving sibilance. While working on that, take another look at the distance to your microphone. We do tend to sneak up on the mic a bit, and that can often intensify sibilance. You’ll often read recommendations to move the mic to the side or rotate it off-axis, however I would avoid making a drastic change in your mic placement. I’ve worked with voice actors who had moved their mic so far off to the side or rotated it so significantly that it drastically changed their tone. Both of those can contribute to less harsh “S” sounds, but should be done in very small increments. I find that in most cases, increasing the distance and angling the mic down from above often helps.

Hardware and Software Approaches to Fixing Sibilance

Just as some of us are more prone to produce sibilance than others, some microphones are simply better at capturing it. Some mics either have a pronounced upper frequency response or are just more susceptible to picking up that part of the audio range. This can crop up with a new (and sometimes more expensive) mic. In many cases, it’s just that awkward-getting-to-know-you phase where you are learning how to use your new instrument. Again, placement/position will make a difference. If it doesn’t become less prominent, that might be a reason to try another mic

Sibilance Quick Simple Fix: EQ

There are some good software tools to take the edge off your S’s. One simple fix could be to take a narrow EQ notch out of the upper frequencies where the worst of your sibilance lives. Highlighting a particularly prominent “S” in your recording and using one of the frequency analysis tools should show where the harshest part exists. A 30 band graphic EQ often lines up with that frequency, or something like the TDR NOVA parametric EQ can be placed in a specific frequency and narrowed appropriately. Since not much else in your vocal range lives in that 5kHz to 10kHz range, a narrow cut can work.

Specialty Sibilance Tools: DeEssers

There are a variety of third-party tools built to provide help in solving sibilance issues in the studio. I often set up clients with the Waves Sibilance tool, mostly because it has one of the more refined user interfaces. It also visually shows you what it’s removing in the waveform, which lets you see what the settings do in real time. Many of the DeEssing tools are unnecessarily cryptic, and it’s sometimes hard to tell exactly what you are adjusting.

The native DeEsser in Adobe Audition is nicely understandable. I also like the controls in Izotope’s Nectar DeEsser (shown above). Unfortunately, you have to get the Standard/Plus version of Nectar to access this – the Elements version is controlled by the software – a very indirect approach).

If you have Izotope RX, the DeEsser is quite good but the controls are a bit less intuitive, so it can take a bit of tweaking to maximize the performance. I’m surprised that they haven’t updated the tool with the interface from Nectar.

An “S” Too Far?

DeEssers are essentially very narrow band Compressors. As with any dynamics processor, things can go bad fast. When you get the settings wrong, you notice it immediately. The result is that your “S’s” turn into “TH’s” – the dreaded “Thylvethter Thyndrome” (in honor of Mel Blanc’s Sylvester the Cat character). Any time you hear that happen, back off your settings until it goes away.

When solving sibilance in the studio, addressing sibilance first at the source, then through mic choice and placement, will reduce the heavy lifting by the software tool. A lighter use of the tool will reduce the tendency toward over processing. Use as light a touch as possible for the best results.

Hot Tip: Tokyo Dawn Records NOVA EQ Makes a Great DeEsser

I’ve been a huge fan of Tokyo Dawn Records NOVA EQ for a long time. Though it calls itself an “EQ” there are quite a few other features under the hood. By using the Threshold control, you can configure it to work as a very effective active DeEsser. It uses the dynamics of your performance to increase or decrease a frequency reduction.

Links to Resources in this article
Blue Cat Frequency Analyzer –
https://www.bluecataudio.com/Products/Product_FreqAnalyst/
SIR Spectrum Analyzer –
https://www.siraudiotools.com/Spectrum-Analyzer.php
Waves Sibilance –
https://www.waves.com/plugins/sibilance
Izotope Nectar Plus –
https://www.izotope.com/en/products/nectar/features/de-esser.html
Izotope RX –
https://www.izotope.com/en/products/rx.html

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