Why does the waist hanging loudspeaker always make a loud noise?
This phenomenon is called self-excited oscillation.Self excitation whistling is a common problem in audio equipment and causes headaches for users. Not only annoying, damaging atmosphere, but also sometimes damage to equipment.The reason for self-excited whistling is that sound amplification takes time. The process is: sound by a microphone amplifier - - horn released by air once again spread to the microphone amplifier, so repeated circulation scream.The occurrence of self-excited oscillation is related to the conditions in the field and the performance of the amplifying equipment. If a cycle longer, most people feel a horn (acoustic echo phase); if the spread to the microphone sound of the horn is small, recycling will become increasingly weak to maintain (amplitude acoustic conditions). A howling occurs only when a particular condition (phase and amplitude) is satisfied.Prevent howling can take the following methods: 1, reduce the volume; 2, the low sensitivity of microphone (that must be close to the microphone to speak); 3, with strong directional microphone; 4, using the anti - interference microphone; 5, access attenuation equalizer, howling band; 6, access frequency shifter, broken ring howling phase; 7, closed sound, microphone and speakers will be placed in different rooms; 8, on the wall of the room to take 9, multi speaker acoustic treatment; small volume, each horn tube in a small area, the volume is very small; 10, using special self suppression equipment.Without changing the environment and the condition of the equipment, changing the position of the microphone and the speaker (wall reflection should be taken into account) to reduce the horn sound into the microphone, find the howling point to the sound amplification equipment does not occur.
Is there a cell phone next to it? Once a cell phone receives a signal, it can make a harsh sound. If it is a contact problem, it usually sounds like a baby
In general, these things far magnetic metals, such as watches or mobile phone or electronic components, because the teacher just sometimes close to the microphone, then there will be interference of electromagnetic interference and the frequency of the original frequency much difference sounds very harsh advice a bit like your teacher
