For the inexperienced, using a microphone may initially seem to be a fairly easy operation. You simply talk or sing into the round bit at the top and a beautifully clear and balanced sound will be emitted from the speakers to wide acclaim from the assembled audience.
The reality however can be very different with feedback, insufficient volume, too much volume or muddy sound quality being an all too common problem. If such issues occur an inexperienced performer may look to the PA system operator for answers but the solution may prove to be closer to home if these problems are the result of poor or inconsistent microphone technique.
Step 1: Optimum Pickup Position
All microphones have an optimum zone within which they pick up sound. The majority of microphones used for live vocal applications are known as Cardioid microphones. Cardioid microphones have the most sensitivity at the front and is least sensitive at the back. This isolates them from unwanted ambient sound and gives much more resistance to feedback than omnidirectional microphones. Cardioid microphones are therefore particularly suitable for loud stages. When using the cardoid microphone it is vital that you are aware of the optimum pick up zone which is usually at the front and centre of the basket. Speaking into any other area of the microphone is likely to produce a low or intermittent signal that can reduce the quality of the sound reproduction.
Step 2: Distance From the Microphone
Singing live produces a highly dynamic audio signal which means that a wide variety of audio frequencies and volumes are produced. The microphone in use should have the ability to deal with all the frequencies likely to be produced from the audio source.
In the case of human vocals this is generally between 50 Hz – 15 kHz and the all quality vocal microphones will be able to capably deal with this frequency range. It is the responsibility of your PA hire operator to supply microphones suitable for vocal use but it is the responsibility of the user to regulate the distance of the microphone from their mouth when the volume of the signal (their voice) alters. When singing quietly you should position the microphone closer to your mouth. As the vocal volume increases the microphone should be moved further away. The idea behind this is that the volume of the sound channelled to the audience does change in proportion with that intended by the performer but not so dramatically that it potentially overloads the speakers with a distorted signal and prevents the sound engineer from having to continuously adjust the gain and output volume of the vocal signal.
As you become more experienced using a vocal microphone you will develop your ability to adjust the distance of the microphone from your mouth as the vocal volume changes throughout your performance but it is certainly worth practising your microphone technique during rehearsals and sound checks. The aim is to produce a signal with as continuous a volume as possible throughout your song but that still has the required emphasis in the necessary parts.
Step 3: Feedback
Feedback produced when an audio signal is continuously picked up by a microphone, amplified by the PA system, emitted by the speakers and picked up by the microphone once again. The result is the increasingly loud howl or hum that is regularly heard during live music events.
Your sound engineer has certain tools at his disposal to reduce the likelihood of feedback including graphic equalisers, limiters and gates but as a performer the key to reducing the occurrence of feedback is to avoid the chance of the microphone picking up its own signal. This includes avoiding taking the microphone near to or in front of the speakers, not pointing the microphone at the on-stage monitors and not shouting or screaming directly into the microphone from a close proximity. Certain venues can be more prone to feedback due to their inherent acoustic properties. If you are concerned by feedback approach your sound engineer who can advise you of any issues due to the venue and recommend any preventative actions you can undertake.
Step 4: Be Nice to the Mic
You may think it looks particularly cool to swing the microphone around your head during a blistering guitar solo but nothing kills a microphone quicker than when it inevitably smashes into the floor/ceiling/drummer’s face. To maintain the quality of the sound produced by the microphone be kind to it. Put it on its stand when not in use, try to avoid dropping it on the floor and resist the temptation to swing it around your head. This is doubly true when you are not supplying the microphone yourself. If you are using an in-house or hire PA system take into account that all the PA equipment in use is not your own and therefore not there to be destroyed in the name of rock and roll. If you are intent on destroying something on stage make sure you are not only in a position to pay for it but also to find a different venue to play in or a new audio visual hire company.
Step 5: Handheld Microphone
Vocal microphones are designed to be held in the hand when being used but to get the best sound quality hold the microphone around the shaft only and not around the basket. This reduces the chance of feedback and maintains the sound quality. Also avoid catching the microphone on clothing and other such items as this will be picked up and amplified by the PA system.
Overall when using a microphone there are many considerations that have to be taken into account but with practise and experience these can become a natural and incorporated part of your on stage performance and have the added benefit of helping to maintain the integrity of the sound.