Audio Feedback – Reasons and Ways to Avoid
Numerous times you might have observed that the speakers suddenly start emitting a shrill noise forcing you to close your ears. This is nothing but audio feedback. Audio feedback is result of creation of loop between the input device (microphone) and the output device (speaker). For instance, a small sound is picked up the microphone and routed to the speaker. But somehow, the output from the speaker is again picked up by the microphone creating an infinite loop. In the process, the severity and decibel level of the sound keeps on increasing taking it to a point wherein it becomes unbearable for human ears. Successive amplification of sound results in audio feedback.
Primary Reasons of Audio Feedback
Majority of the times, when a live microphone is placed near the speaker, audio feedback occurs. If the speakers are pointing towards the microphone, in all probability audio feedback will occur. Audio feedback can occur even during live events and concerts thus professionals overcome this problem by placing the main speakers at a distance and placing smaller speakers (spot speakers) near the performer or the presenter.
Audio feedback can also be prevented by adopting the handyman trick. Herein, you need to have a good sound system with equalizer options. The next step is to purposely create an audio feedback and listen at what frequency the feedback occurs. Turn down or fine tune those particular frequencies at which the audio feedback occurs. Professional sound engineers are very good at this even with analog equalizers. You however can overcome this problem by taking help of a graphic equalizer.
As audio feedback problem is very common, automatic anti-feedback devices have been developed by companies to do away with issue. Termed as feedback destroyer or feedback eliminator, the device automatically detects audio feedback loop and makes necessary adjustments to kill the loop. Only a chirp is produced for a moment which conveys that adjustment has been made by the feedback destroyer. Notch filters are also used for arresting audio feedback, however their working principle differs. Hush devices are used for ground-loop noise elimination.
While giving a presentation or a performance, if an audio feedback occurs, only a professional can rectify the issue. If you try to do it yourself, in all possibility it will recur and disturb you again and again. Thus, the momentum that you have been building with the presentation might be lost if the audio feedback occurs at the oddest moment. The solution thus is to have a sound system with inbuilt feedback eliminator. Now those kinds of systems are costly if you are thinking of buying it. The best option thus is to hire a sound system from a rental company.