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Imagine you are at a concert. The lead guitarist reaches for the volume on his amplifier and turns it too far. Suddenly a piercing screech rings through the air, and you find yourself holding your ears in pain. What did you just hear? How did it get so loud?

What you heard at the concert was audio feedback, which is a great example of a positive feedback loop. Click here to explore this common feedback loop.

Worked Example

Question: Why did the feedback loop happen? If you were the guitarist on stage, what could you have done to limit or prevent this feedback effect from occurring?

After a certain threshold volume is passed, the sound emitted from the amplifier resonates with the strings on the guitar, causing a vibration. This noise is then picked up by the guitar and transmitted back into the amplifier, creating a loop. However, each time the sound is sent through the loop, it is magnified and amplified. A simple solution to this problem would be to turn the volume down, or to keep the strings from vibrating. If the feedback lasts too long, it can damage the amplifier.