The simplest PA system consists of a microphone, an amplifier and one or more speakers. Whenever you have those three components, you have the potential for feedback. Feedback happens when the sound from the speakers makes it back into the microphone and is re-amplified and sent through the speakers again, like this:
Home SparkNotes â History Study Guides â The Great Depression (1920â1940) â The Roaring Twenties and the Jazz Age: 1920â1929.
The stock market crash of 1929, usually cited as the beginning of the Great Depression, was preceded by the Roaring '20s, a period when the American public discovered the stock market and dove in head first. The crash wiped out many people's investments and the public was understandably shaken.