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.
Introduction. Calvin Coolidge (1872-1933), the 30th U.S. president, led the nation through most of the Roaring Twenties, a decade of dynamic social and cultural change, materialism and excess.