You’ve walked on stage and everything seems okay; you start to sing, but instead of hearing your voice an ear-piercing screech comes out of your speakers.
Your system is producing feedback and your performance is compromised!
Although this is every singer’s nightmare, it is quite avoidable; follow our guide and you shouldn’t have to worry about experiencing feedback on stage again.
Feedback occurs when too much of the sound from your speakers is picked up by your microphone and starts an audio loop. This circulates around your system rapidly getting louder until it produces a continuous noise that is unpleasant (and potentially damaging) for both you and your audience’s ears. It is something that most singers will experience at some point; however there are several ways to help avoid feedback and stop it being a regular problem at gigs.
The microphone you use can make a huge impact on your susceptibility to feedback on stage. Firstly, don’t try to use a mic designed for the studio in a live setting. Although your vocals may sound amazing through a large-diaphragm condenser mic, they are generally not resistant enough to feedback in a live setting – neither are they rugged enough for stage use. Live microphones (such as an SM58) are built to withstand the rigors of the road and are designed to offer the best compromise between vocal sound quality and feedback rejection in a live environment. When choosing a live microphone take note of the “gain before feedback” figure. Some microphones, such as the EV N/D967 and Audix OM7, are specifically designed to offer a maximum amount microphone gain before feedback occurs. On the other hand, they do not produce such a rich vocal sound as other microphones, such as the Sennheiser e965 or Neumann KMS 104, which are primarily designed with vocal sound quality in mind whilst also offering reasonable levels of feedback rejection. With this in mind, if you sing in a particularly loud rock band you will need to consider the gain before feedback of your microphone much more than a singer performing in an acoustic jazz group.
Once you have found the right microphone, you need to make sure you hold it correctly. If you use a microphone stand this simple enough, however if you like to hold your microphone in your hand there are a few things to keep in mind. First, make sure that when you move around on stage you don’t point the grill of your microphone towards your PA speakers or monitors. You also may want to try placing your microphone so that the grill is angled slightly upwards in order to get better rejection from the sound coming from your floor monitors. One mistake that many singers make is to hold their microphone too high up and cover up the bottom of the grille. Not only does this adversely impact the sound of the mic but it noticeably reduces its resistance to feedback. If you insist on cupping your microphone grill (in the case of beat-boxers, for example), you may want to buy a mic that is designed to cope with better it such as the Audix Fireball V.
Direct sound from your speaker into your microphone is not the only potential cause of feedback to worry about. If you are performing somewhere with low ceilings or very close to a wall, there is a good chance you may run into feedback problems caused by the sound from the speakers being reflected back into your microphone. A way to avoid this is to hang a curtain behind you on stage to absorb some of these reflections and if possible, move away from the back wall of the venue. If these problematic reflections are caused by low ceilings, it may help to slightly angle you mic away from the ceiling (so the grille is facing towards the direction of the floor) – however if you do this you will probably need to turn down your floor monitors slightly as your microphone will pick up more sound from them.
In Part 2, we will look at how to setup your PA system correctly as well discover how technology can help to eliminate feedback on stage.
Chris Kennedy is the principle product reviewer for VoiceCouncil Magazine. He is also a singer-songwriter and composer, performing and writing in a range of styles from rock to jazz. Chris has released several albums as a solo artist and with his group The New Inventions. When he isn’t performing live, Chris also works as a live sound engineer and writes and records film music in his studio. You can find more about him on his website: http://www.chriskennedymusic.co.uk