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 social and cultural features known as the Roaring Twenties began in leading metropolitan centers, especially Chicago, New Orleans, Los Angeles, New York City, Philadelphia, Paris, Berlin and London; then spread widely in the aftermath of World War I.The United States gained dominance in world finance.y the middle of the decade prosperity was widespread, with the second half of the decade especially in Germany known as the  Golden Twenties . The spirit of the Roaring Twenties was marked by a general feeling of discontinuity associated with modernity and a break with traditions.