acoustic feedback的意思|示意

Acoustic feedback refers to a sound loop that is created when a sound from the loudspeaker to the microphone is picked up and augmented. It is also commonly referred to as a \"howling\" sound. Though this phenomenon has been studied since the 1950s, it has become more commonplace as more and more sound systems involving microphones, amplifiers and loudspeakers have come into use.

Specifically, acoustic feedback occurs when a microphone picks up sound from a loudspeaker and then amplifies it to the point that the sound is picked up by the microphone again, thus creating a loop or feedback sound. The volume of the sound can increase each time it cycles through the loop, resulting in a sharp rising tone, though in most cases, the sound eventually dissipates because of the other noises that intervene.

The most common place where acoustic feedback occurs is in places where a microphone is being used for vocal performance. The sound of the person's voice is picked up by the microphone, amplified, then sent back out to the loudspeakers, where it is picked up again by the microphone. This is why sound engineers often ask performers to lower the volume of their amplifiers when they hear the sound of acoustic feedback.

In order to prevent acoustic feedback, it is important to use the proper microphone and sound system setup. The microphone should be placed as far away from the loudspeaker as possible, and all unnecessary sound sources should be removed. The gain control knob on the microphone should also be adjusted to the lowest possible setting. Finally, sound engineers should use graphic equalizers to lower any frequencies that are being amplified, as this will help to prevent unnecessary feedback.