If you are an avid fan of live music performances, you may have noticed how some singers' mouths will regularly touch their respective vocal microphones. Some artists have picked up the habit by observing their peers, while others do so for specific performance-enhancing purposes.
Why do singers put their mouths on the microphone? The primary reason singers put their mouths directly on microphones is for an improved signal-to-noise ratio. By keeping the mic at the mouth, the microphone will effectively pick up more of the voice and less of the background instruments/noise, thereby improving vocal intelligibility.
This article will go over 5 reasons why singers benefit from holding their microphones up to their mouths. We'll also consider the situations where this proximity may not be the best method of capturing vocals.
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• Top 11 Best Online Resources To Learn How To Sing
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Improved Signal-To-Noise Ratio
As discussed in the opening paragraphs, the primary reason a singer will hold the microphone to their mouth is to improve the signal-to-noise ratio.
The signal-to-noise ratio (or simply SNR) is the ratio of the power of the intended signal level to the power of the noise level. Here, “signal level” refers to the intended sound source (the singer's voice), while the “noise level” refers to everything else.
Noise level refers to a part of an electric signal that includes any miscellaneous sounds, such as other instruments and crowd noise. To get some separation between your voice and other sounds, you need to raise the amount of “good” signal in the mic's output versus the “bad” signal.
For the singer, this often means putting the mic as close to the lips as possible without overloading the mic and causing distortion.
The average rock concert generates 120-129 decibels of noise. Crowd noise, coupled with the music, makes it very difficult for the singer to hear his voice. A singer can increase their volume to match the crowd's noise by putting their mouth on the microphone.
Note that microphones also inherently have a signal-to-noise ratio specification (before any environmental noise is taken into consideration). To learn more about this mic spec, check out my article What Is A Good Signal-To-Noise Ratio For A Microphone?
Reducing The Chance Of Microphone Feedback
By improving the signal-to-noise ratio, the overall level gain of the microphone signal chain can be lowered. Having the microphone closer to the mouth will cause the microphone to output a stronger signal, which may overload the mic and cause distortion, so it's a good idea to bring the level down anyway.
By reducing the gain and the overall capture of background noise, the microphone will be much less likely to cause a feedback loop with the loudspeakers/public address system.
A feedback loop happens when the microphone picks up the sound of the loudspeakers, which is then amplified back into the loudspeakers in a positive feedback loop. The result is the screeching/squealing noise we're likely all familiar with.
Holding the microphone to the mouth and keeping it away from the loudspeakers will help tremendously in the fight against feedback.
To learn more about microphone feedback and how to eliminate it, check out my article 12 Methods To Prevent & Eliminate Microphone/Audio Feedback.
Live performers are paid to entertain. For some singers, this means pacing around the stage, interacting with the audience and being as animated as possible.
It's not easy to keep a mic steady while you are constantly on the move. Keeping the mic on the mouth/chin helps the singer stabilize the microphone and allows for a more uniform sound throughout the performance.
Many singers (and rappers, in particular) grip the mic just below the grille while allowing the thumb to touch the top of the mic.
The top of the thumb rests on the chin, allowing the mic to remain near the mouth, which helps the singer produce consistent sound for loudspeakers in concerts and live performances.
To learn more about mic positioning for live performance, check out my article How To Hold A Microphone When Singing Live.
The Proximity Effect
Live vocal microphones are nearly always directional, generally having a cardioid polar pattern. The popular cardioid pattern picks up sound in the direction the mic is pointing and rejects sound from the back of the microphone.
Directional microphones exhibit a phenomenon known as the proximity effect.
This effect essentially states that as the distance between a sound source and a directional gets smaller, the bass response of the microphone will become stronger relative to the high-frequency response. This has to do with the fact that lower frequencies have longer wavelengths than higher frequencies.
So by holding the microphone to the mouth, a singer can exploit the proximity effect to give their voice a “bass boost”.
For more information, check out my article In-Depth Guide To Microphone Proximity Effect
A fifth, less technical reason why singers hold their mics to their mouths is for the aesthetic. Sometimes, it's about looking cool.
Whether the singer is just employing the techniques they have learned from their favourite singers or are well aware of the benefits of holding the mic close, aesthetics may certainly play a role.
Why Singers Pull The Mic Away From Their Mouth
Of course, some situations or portions of a vocal performance are best captured by a microphone at some distance from the mouth.
You may notice some singers back away from the mic as they sing a high/loud note. This ties into utilizing techniques for a more uniform sound in the vocal performance.
If the vocal becomes louder, moving away from the microphone can produce a more consistent response in the playback and/or recording system.
Situations Where Distance Between The Singer And Microphone Is Preferred
Thus far, we've focused our discussion on live performance, where maintaining a consistent and close microphone position greatly benefits singers.
However, in many recording studio situations, it's actually best to keep some distance between the vocalist and the microphone.
Studio environments offer the benefit of isolation/vocal booths, which provide an acoustically dead environment with little to no background noise (except for perhaps some headphone bleed of the reference track).
The studio monitors are typically positioned in another room, meaning there is virtually no risk of feedback, either.
So, in these situations, we can afford to have the vocalist further from the microphone. Having some distance between the singer and the mic has several benefits.
Having physical space between the vocalist and the mic reduces the chances of overloading the microphone with plosives (energy from hard consonants). A pop filter can be positioned between the signer and mic to improve plosive protection further.
The vocal sound waves can develop more naturally before reaching the mic. A microphone positioned at the mouth will tend to sound like having your ear at the singer's mouth. Having some distance produces a more optimal/natural result.
If the vocalist moves slightly, the difference in the bass response due to the proximity effect will be less than if the singer was closer.
Positioning the microphone away from the vocalist on a mic stand means that the singer will not be holding the mic. This offers the benefit of reduced mechanical noise (as the grip changes) and ensures there's no obstruction to the mic grille and capsule (due to potentially incorrect grip positions).
For more information on microphone placement, check out my article Top 23 Tips For Better Microphone Placement.
Choosing the right microphone(s) for your applications and budget can be a challenging task. For this reason, I've created My New Microphone's Comprehensive Microphone Buyer's Guide. Check it out for help in determining your next microphone purchase.