Feedback is a very common problem with sound systems and when amplifying music or voices. We all know the unpleasant squeal when someone picks up a microphone and we instinctively want to cover our ears. Sound amplification is an extremely complicated phenomena of transducing electrical signals to audio signals, hence why feedback can occur quite easily. There are however a few steps that you can take to avoid this embarrassing and off-putting occurrence.
Feedback occurs when there is a repeating cycle of signals between a microphone and a speaker. A sound that is coming out of the speakers is picked up by the microphone and then the microphone sends it back through the speakers and so the nasty sounding audio oscillation builds up. An obvious solution would be to turn down the microphone and/or the speakers in question. Bring down the volumes on the microphone and monitor or speakers as much as possible and if there is music around the voice signal then turn that down as much as possible too.
The placement of the speaker in relation to the microphone can be optimised. A standard live microphone mainly picks up a signal in front of it and out to the sides around 45 degrees. This is called a cardioid or hyper cardioid microphone. So make sure the speaker or monitor is not in the main pick path of the microphone. Ideally the person speaking or singing should have the microphone pointing away from the speakers and monitors.
Equalisation or EQ units can help to alleviate feedback problems. With a full band range EQ unit, you should be able to isolate the offending frequencies that are most prone to creating feedback. This is most often in the range of 2 to 4 Khz as this is the range of the human voice. So attenuating the volume of these frequencies can lower the likelihood of feedback. But of course any manipulation of the frequencies will change the quality and tone of the sound going into the microphone. So a careful compromise has to be found that reduces feedback without spoiling the sound of the voice. Reducing the gain on your EQ and reverb units may also help.
Finally, you may need to look at the space you are amplifying your sounds in. Maybe it has a resonant frequency that causes feedback problems. If the space is very reverberant with lots of hard or shiny surfaces, then dampening the space may help reduce your feedback problems. Ideally before you undertake any speaker installation, you can employ the services of an acoustic engineer to assess the problem areas of your room if you are really affected by this problem.
Feedback occurs when there is a repeating cycle of signals between a microphone and a speaker. A sound that is coming out of the speakers is picked up by the microphone and then the microphone sends it back through the speakers and so the nasty sounding audio oscillation builds up. An obvious solution would be to turn down the microphone and/or the speakers in question. Bring down the volumes on the microphone and monitor or speakers as much as possible and if there is music around the voice signal then turn that down as much as possible too.
The placement of the speaker in relation to the microphone can be optimised. A standard live microphone mainly picks up a signal in front of it and out to the sides around 45 degrees. This is called a cardioid or hyper cardioid microphone. So make sure the speaker or monitor is not in the main pick path of the microphone. Ideally the person speaking or singing should have the microphone pointing away from the speakers and monitors.
Equalisation or EQ units can help to alleviate feedback problems. With a full band range EQ unit, you should be able to isolate the offending frequencies that are most prone to creating feedback. This is most often in the range of 2 to 4 Khz as this is the range of the human voice. So attenuating the volume of these frequencies can lower the likelihood of feedback. But of course any manipulation of the frequencies will change the quality and tone of the sound going into the microphone. So a careful compromise has to be found that reduces feedback without spoiling the sound of the voice. Reducing the gain on your EQ and reverb units may also help.
Finally, you may need to look at the space you are amplifying your sounds in. Maybe it has a resonant frequency that causes feedback problems. If the space is very reverberant with lots of hard or shiny surfaces, then dampening the space may help reduce your feedback problems. Ideally before you undertake any speaker installation, you can employ the services of an acoustic engineer to assess the problem areas of your room if you are really affected by this problem.