Vocal Chords: 6 Ways To Beat Common Sonic Gremlins

SIBILANCESingers can produce “s” and “sh” sounds (known as “sibilants”) in the range of 3kHz to 10kHz, and some vocalists produce more sibilance than others. So, if you’re recording a singer with a condenser mic that has a rising high-frequency response, you might hear annoying hisses. If you want to smooth out the “s” sounds, try one of these fixes.
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SIBILANCE
Singers can produce “s” and “sh” sounds (known as “sibilants”) in the range of 3kHz to 10kHz, and some vocalists produce more sibilance than others. So, if you’re recording a singer with a condenser mic that has a rising high-frequency response, you might hear annoying hisses. If you want to smooth out the “s” sounds, try one of these fixes:
• Use a de-esser or a multiband compressor set to compress from 3kHz to 10kHz, and with a short attack and release time (Figure 1). Or use a compressor with a side chain, and boost the side-chain signal at around 7kHz.
• Try a mic with a flatter frequency response, such as a Shure SM7, ElectroVoice RE-20, Neumann U87, Shure KSM32, or any ribbon mic.
• Bring in your favorite EQ, and turn down the highs around 7kHz to 10kHz.

“NATURAL” DISTORTION
I’ve recorded singers whose voices sounded like distortion. It wasn’t the mic or the preamp overloading—it was just their voice. If you don’t want that effect, try one of these solutions.
• In a multiband compressor, enable the filter from 2kHz and up. While the vocal track is playing, gradually turn down the threshold so that the compressor kicks in when the singer gets loud, and their voice gets edgy.
• Mic the vocal about 45 degrees to the side. Edgy-sounding high frequencies radiate from the mouth mostly straight ahead, so a mic placed away from the front will pick up less edginess and sibilance.

TOO BOOMY
Let’s look at the other end of the spectrum: lows. When a vocalist sings very close to a microphone, the sound becomes bassy. That’s due to the proximity effect—the rise in lowfrequency response of directional microphones at close-miking distances. The closer you get to a cardioid, supercardioid, or hypercardioid mic, the bassier the reproduced tone.
• To diminish proximity effect, sing at least eight inches from the mic. Place a hoop pop filter about four inches from the mic, and ask the singer to use his or her four fingers as a spacer between mouth and hoop before each take.
• If the singer must be close to the mic for isolation, turn down the lows in your mixer, plug-in, or engage the mic’s low cut filter if it has one. Proximity effect can extend all the way to 500Hz, so if you roll off around 100Hz, there may still be a 500Hz bump in the vocal signal that produces a puffy, “cupped hands” tone. Take down 500Hz a bit as well.
• Try an omnidirectional mic (or set the mic’s polar pattern to omni). Omnis have no proximity effect. You’ll hear more room acoustics when you use an omni pattern, however, so you may need to position your mic closer than usual.

PING-PONG DYNAMICS
Vocals tend to have a wider dynamic range than their instrumental backup. Sometimes, vocalists blast the listener, and, other times, they sing quietly and get buried in the mix. There are ways to deal with this.
• Back away from the mic on loud notes, and come in closer on quiet notes. Listen over headphones while doing this to judge the right distances.
• Use a compressor. A typical setting might be a 3:1 ratio, and 6dB of gain reduction with a soft knee. An extreme setting might be a 4:1 ratio and 10dB of gain reduction.
• Use mixer automation or track volume envelopes to turn down loud phrases. This approach tends to sound more natural than compression.

POPS
When a vocalist sings plosive sounds with the letters P, B, or T, a turbulent puff of air shoots out of the mouth and hits the mic diaphragm, causing a thump or small explosion. This is easy to fix. Simply place the mic out of the path of the rush of air by positioning it above or to the side of the singer’s mouth. You could also put a hoop pop filter between the mic and singer. This type of pop filter reduces high frequencies less than a foam windscreen, and is more effective.

PHASE CANCELLATION
When you record a singing guitarist, the vocal might sound filtered or hollow because of phase cancellation (the reduction in the volume of certain frequencies when two equal signals from different distances are “combined” by the mic) between the vocal mic and guitar mic. Try one of these solutions.
• Mic the voice and guitar very close. Roll off excess bass with your mixer EQ. Try miking the guitar three inches away, and about three inches to the right of the soundhole toward the neck.
• Use a pickup on the guitar instead of a mic.
• Place two bidirectional mics so the tops of their grilles touch. Aim the “dead” side of the vocal mic at the guitar, and the dead side of the guitar mic at the mouth.
• Place just one mic—or a stereo mic—midway between the mouth and guitar, and about one foot out front. Adjust the balance between voice and guitar by changing the mic’s height.
• Delay the vocal mic signal by about 1–3ms to help the two signals get in phase with each other.

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Fig. 1. A multiband compressor plug-in set up as a de-esser.