WEBVTT - What causes that howling sound in PA systems?

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<v Speaker 1>available now exclusively on iTunes. Hi. I'm Marshall Brain with

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<v Speaker 1>today's question, what causes that howling sound in p A systems?

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<v Speaker 1>A simple p A or public address system consists of

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<v Speaker 1>a microphone and amplifier and one or more speakers. Whenever

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<v Speaker 1>you have those three components, you have the potential for feedback.

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<v Speaker 1>Feedback occurs when the sound from the speakers makes it

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<v Speaker 1>back into the microphone and is re amplified and sent

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<v Speaker 1>through the speakers. Again. Imagine that you place the microphone

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<v Speaker 1>in front of a speaker. Now you tap on the microphone.

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<v Speaker 1>The sound of that tap is through the amplifier, comes

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<v Speaker 1>out the speaker, and it re enters the microphone. That

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<v Speaker 1>cycle repeats over and over. This loop happens so quickly

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<v Speaker 1>that it creates its own frequency, which we hear as

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<v Speaker 1>a howling sound. The distance between the mic and the

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<v Speaker 1>speaker has a lot to do with the frequency of

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<v Speaker 1>the howling, because that distance controls how quickly the sound

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<v Speaker 1>can loop through the system. If you're setting up a

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<v Speaker 1>sound system and you want to avoid feedback, there are

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<v Speaker 1>a few general rules that can help you avoid the problem. First,

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<v Speaker 1>make sure the speakers are in front of the microphone

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<v Speaker 1>and pointing away from the microphone. If the speakers are

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<v Speaker 1>behind the microphone, then feedback is nearly guaranteed. Second, use

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<v Speaker 1>a unidirectional microphone. Third, place the microphone close to the

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<v Speaker 1>person who's speaking or performing, And fourth, if you have

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<v Speaker 1>access to an equalizer, dampen the frequencies where feedback is occurring.

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