That Awful Squeeling Noise

The person lifts the microphone and starts to speak and suddenly a high pitched whine explodes out of the speakers and compels everyone in the room to suck in their breath and cover their ears. If you've ever experienced this then you really can't forget it.

The cause is something called positive feedback. The microphone converts sound waves into electrical waves which are in turn fed into an amplifier which makes them stronger and sends them to speakers where magnets convert the amplified electrical waves back into sound. This is great until the amplified sounds feeds back into the microphone, gets amplified again, comes out of the speakers even louder, and feeds back into the microphone in an endless feedback loop that increases the volume until the amplifier is driving as strongly and as loudly as it can or something blows up or someone turns the volume off or the speaker wisely covers the microphone or stops pointing it at the speakers. The reason that it picks one particular frequency or ranges of frequencies (the squeel) has to do with the design of the amplifier which usually has a "sour" spot where it is prone to instability and feedback.

Ever wonder why the church places such a strong emphasis on regular meeting attendance? What are they afraid of if people attend irregularly? That they'll turn evil? Maybe, but I really don't think that church attendance has much affect on people's behavior. I think that it is because church attendance creates a mental positive feedback loop. In church, the message is heard and repeated. The members hear the message and it resonates with their beliefs and it gets amplified. This causes them to echo the message which makes it stronger to them, but also triggers similar feelings in everyone around them. This sets up a positive feedback loop that reinforces the message in everyone.

The church fears that without that regular reinforcement then the feelings will fade and doubts and reason will have more influence when the church's message isn't being amplified.

This effect is sometimes called an echo chamber or a herd mentality and it is effective in religion. But it is also used in politics and media to try to influence people to do or believe things that they wouldn't do on their own.

So, challenge yourself to put your hand over the microphone and get to a quiet place where you can think things through on your own without giving inappropriate importance to what the herd is saying.