by Pablo Bellinghausen –
Once the PA system has been set up and the microphone plugged in, microphone technique is the single most powerful tool a singer has at their disposal to make their performance sound as good as possible. It is also considered one of the more mysterious aspects of a singer’s toolkit, with contradictory advice often bandied about by musicians, almost as if they were folk remedies!
However, armed with a firm grasp on the electrical, mechanical, and acoustic fundamentals workings of microphones and speakers, we can separate good advice from tips that work only in specific circumstances, and fail disastrously in others.
Microphone angle and distance
The distance from the singer to the microphone changes two things; the first one is the tone of the mic, which will be far bassier when up close to the mouth due to what is called “proximity effect”. Singing right up into the mic will also slightly enhance plosives, which might be a problem on some performers. Singing more than a few inches away will, on the other hand, give you a thinner tone, with some of the low end shaved off from the voice.
Most microphones are designed with an ideal distance in mind (usually around 5–8 inches), and compensate for this effect through the correct amount of bass filtering. Some, like the Neumann KMS105, are designed to be used from further away, and will sound muddy if one gets too close; some, like the Audix OM5, are designed to be used right next to the mouth, and will lack bass at a larger distance.
The second thing that changes with distance is, of course, the volume of the vocal. As obvious as this is, however, there are often misunderstandings about what this entails. The most important thing to understand is the inverse square law: this means you get a level drop of 6 decibels (which feels like a noticeable drop in volume but not quite a halving of it) every time you double the distance. Possibly an easier way to think about it is this: one quarter of the distance equals roughly to a doubling of the perceived volume.
This means that when you’re several inches away, slight head movements won’t change the volume that much; however, if you’re right in front of the microphone, even small differences in distance will cause noticeable drops and boosts in volume.
Some people claim that singing too close to a microphone amounts to bad technique, but it isn’t actually the case; the most important thing when performing is to keep the distance consistent (which does become more difficult when singing close to the mic, due to small differences in distance being proportionally larger). Singing 1–3 inches from the mic is actually best practice when singing loud rock or metal music in small venues. Any excess bass, as long as it remains constant, can be fixed on the mixer.
A more advanced technique is to slightly move the microphone depending on the volume, or intention, of the vocal part, by singing quiet, intimate parts closer, and louder bits further away, sometimes even single syllables. When well-executed, this can actually smooth out the vocal and add slight differences in tone that enhance the song, but it requires a lot of practice, or else it can do more harm than good.
The microphone should always aim straight at the face, but doesn’t actually need to be placed horizontally; although more nasal singers should indeed keep the mic horizontal, angling the mic towards the bottom of the nose could help with projection on quieter vocals.
In addition, putting the mic slightly to the side but still pointing at the mouth can help with plosives and tame particularly brash, sibilant, or bright voices.
Preventing and Fighting Feedback
That familiar squealing sound that happens when a microphone picks up its own sound from a speaker, and therefore sending the signal back to it, can be an engineer’s nightmare in smaller stages. Any singer who has had experience playing next to a drum kit in a small stage will be familiar with it; it crops up at inopportune moments, can catch both the performer and the engineer off guard, and will force the vocals to be played back at a lower volume, lest your ears be assaulted by constant screeching. If you’ve been to a gig and you can’t hear the main vocal, this is likely to be the reason why.
Even though the fault will often be placed on the sound engineer, the singer is actually the person most able to stop it. Here are the three most important tips to prevent feedback in pretty much any venue:
- Sing closer to the microphone
One can spend hundreds of pounds on the “most feedback-resistant mic”, but it’s important to note that the difference in gain-before-feedback between vocal handheld models is almost never more that what can be achieved by placing the mic as close to the mouth as possible. As mentioned before, due to the inverse square law, the volume of the vocal increases exponentially when you get very close to the diaphragm of the mic, which renders the instruments and speaker “bleed” comparatively much lower.
Moving the mic’s diaphragm from 16″ to 2″ away is an increase of about 18 dB, which is the same as having a power amp that is 8 times more powerful, or 6 more speakers’ worth of volume, with no added cost or hassle!
- Keep the foldback monitors in the microphone nulls
For this we need to go back to the polar patterns we saw in our previous instalment. If you are using foldback monitor speakers to hear yourself onstage instead of in-ears this is critical, and can make all the difference between an amazing performance and an embarrassing one.
Basically, at any moment in time, the foldback speaker (and, in small stages, even the main speakers) should remain around the microphone’s least sensitive point. For a cardioid mic, this is right at the back; for a super or hypercardioid mic, it’s around 110–120 degrees from the front.
When confronted by unexpected feedback, a singer without this knowledge will do what feels most natural, which is put the microphone close to their body and perpendicular to the speaker, which both creates a reflection from the body and puts the capsule in a rather sensitive position – this will, of course, make matters worse. It is rather unintuitive to have to “aim” the microphone’s back to the very speaker that is screeching, but since the attenuation at the back of a cardioid mic can be of up to 30 decibels, it really is the one thing that can stop it in its tracks.
- Don’t cup the microphone
Putting one’s hand around the grille, or “cupping” the microphone, is something that is seen a lot in more urban performers, mainly because it looks pretty cool and aggressive. It also sometimes comes from a misunderstanding of how microphones are designed, since some people believe it somehow “keeps” the sound inside the mic better.
However, due to the way directional capsules are designed, this actually completely messes up the sound. Basically, a microphone capsule becomes “directional” by combining sound from the back and the front in a certain way. If you block the back of the grille, you block the sound from the back and cause the pickup pattern to become omnidirectional. That means that, counterintuitively, if you block the back of the grille, it will pick up more sound from the back! This can of course cause the microphone to feed back straight away.
Some pretty big artists do do this, but they get away with it in large stages, and when using in-ear monitors, which means there are no foldback speakers to worry about. As cool as it looks, however, and even if it doesn’t feed back, the reflections from the hand will cause the sound to become muffled and strange due to phase cancellation in the upper frequencies. There is no real upside to this for an experience performer.
Dealing with plosives
Plosives are that popping or crackling sound caused by large, short bursts of air coming from the mouth when pronouncing P, F, T, and K sounds, but can also happen with fricatives (F and S sounds). The sound is mostly low frequencies, which can be filtered out at the mixer, but sometimes contain higher frequency distortion that will be clearly audible in a mix.
By far the best way to deal with this is to actually practise pronouncing these sounds more softly; most of the time we do, and it’s just a bad habit that comes from stressing the wrong letters in an attempt to enunciate more clearly. This can be done by placing a sheet of paper a couple of inches away from the mouth, and to sing in a way so that it moves as little as possible.
If this is still a problem (or if you don’t have the time to practise this for whatever reason) then you can always buy a Popper Blocker insert, which goes inside the microphone grille, and removes most stray pops at the expense of some of the sound quality.
Once you have taken into account these variables and made them part of your singing routine, you will invariably end up more comfortable at gigs, both you and the audience will be able to hear you better, and performance should become more rewarding in general. Happy singing!