What Is Sibilance And How To Avoid Or Fix Its Effect When Recording Vocals

Ssssooo , what is sibilance ?

Sibilance is the worst. Nothing screams “unseated vocal” like a bunch of “s”s and “t”s that hop right out of the mix. The issue with taming sibilance is that it lives right in the presence and “shiny” range of the vocals – that nice top end down to about 2-3k.

Imagine recording the following phrases and you'll get an idea of how sibilance occurs.

• Six sizzling sausages
• Sing a Song of Sixpence
• She sells sea shells on the sea shore

This article will be about taming sibilance – and the pros and cons and trickery of each mechanism for doing so.

Avoiding sibilance at the source

Sibilance comes from an exaggeration of sound that projects from the roof of the mouth. Certain tongue shapes, space in the front teeth, shape of the palette, or just a learned way of speaking can produce overly sibilant delivery. Knowing this, there are a number of ways we can try to deal with problem before it hits the tape… err … computer (2012 right?).

Choose the right mic!
This almost goes without saying, but if the vocalist is overly bright, you might want a darker microphone. A ribbon mic, a softer dynamic mic (like an RE20), or a vintage sounding condenser (U67), might be a good grab. Something that has a rolled off, smooth top end, that will take well to EQ. There is no con to this approach.

Choose the correct mic position.
You may want to tip the mic a bit off axis, aiming it slightly left or right of the mouth, or perhaps somewhat down. Angling the mic will mostly change the way the treble range is picked up, as lower frequencies are somewhat less directional. The con is that the evenness of the frequency response will be somewhat disrupted by grabbing an off-axis response.

The bubble gum trick
If sound projecting from the upper palette is the problem…. eliminate the upper palette. Have the vocalist chew up some gum and stick it to the roof of his/her mouth. This will cut down the sibilance significantly. The big con here is that this can be awkward for a performer – if it throws off the performance or sense of pitch, it's not worth it. But it's an option.

Managing sibilance in the mix

The issue with sibilance is too fold. First – because of the way we hear, we are more sensitive to higher tones even at lower volumes. So even if the “s”s and “t”s are below the other vocal sounds, we're still gonna hear them clear as day. Second, sibilant sounds are very fast. So here's a few ways we can deal with sibilance effectively.

Manually ride the fader
Hear an “s”, turn it down. This is a transparent approach. The con is that this is time consuming.

Wideband De-Ess
Another basic approach, this is compression that is reacting only to the frequency range. This is much faster than fader riding, however, it tends to leave the leading edge of the “s” unaltered. It makes your sibilant sound less intrusive but spikey, and may be just as annoying. The other con is that you'll tend to catch some of the treble of non-sibilant words and pull down the overall “spark” of the vocal.

Frequency selective De-Ess
This is the same as wideband, except instead of turning the whole signal down, you're just turning down the treble range, as opposed to the whole of the signal when it triggers. This is good for evening out the tone, but has all the drawbacks of wideband, plus it induces eq artifacts (although they are fairly minimal).

So those are the basic 101 techniques. Here's some that can get better results, although they require a bit of trickery. I'll start with my favourite.

Pre-triggering the De-esser
This is a really cool technique. It's a major pain in the ass to set up in analogue mixing, but it's easy in digital. Make a copy of your vocal on a separate track. Move the copy ahead of the main vocal by 50ms. Put a De-Esser, or a multi-band compressor (like Waves C6) – something with an external sidechain – on your main vocal. Key it to the copy.

Through this setup, every time an “s” comes through on the copied signal, it will activate the de-esser on the main signal – but it will do it about 50ms earlier than when the actual “s” from the main signal would occur. This allows the de-esser to reach peak gain reduction BEFORE the “s”. If you set the release for about 100ms, you'll knock out that “s” sound without leaving any spikes on the leading edge. This is a very transparent way to do this.

Over De-Essing
Another way to get rid of “s”s is to go overboard with the de-esser, so that it's working even on parts of the vocal that aren't sibilant. If you then feed this into an EQ, you can boost your high end back up to regain your lost treble. The pro of this is that it has the added benefit of making the treble of the vocal very present without making the “s”s jump. The con is that the high end will almost assuredly become less smooth unless you are using a really good de-esser and treble boost. I use this technique on vocals that only become sibilant once I add a lot of high end to them – which is fairly common in Pop/Hip-Hop/Dance productions.

Smooshing your high end
This one takes a little guts. One of the beautiful properties of minimal phase EQ, is that if you use the exact same EQ and do the exact same amount of boost, followed by the exact same amount of cut, you will nullify your artifacts and come out with the same signal as when you started. Using this principal, you can add like 10-20db of treble gain to your vocals, compress the vocals, and then do the same amount of attenuation after the compressor and get a surprisingly transparent form of de-essing. It sounds weird because it's so extreme, but you get your normal compressor reacting more to the sibilance. Give it a try, you may be surprised. The major benefit to this is that it works well in the analogue realm, not just the digital.

How do you deal with sibilance ?

There are other techniques for easing out sibilance. These are the ones I've found most useful. I should also say that using a combination of these techniques will probably get you further with less artifacts. If you have your own techniques for approaching sibilance, please share in the comment section below!

This article is sponsored by Quiztones frequency ear training apps for Mac OS X & iOS. Quiztones is a frequency ear trainer for amateur and professional audio engineers, producers, and musicians. Quiztones is brought to you by Audiofile Engineering and is available as a mac app or mobile version for ipad or iphone via the App Store.