20th-Century Music OverviewCultural Background - After two world wars, composers broke old rules, mirrored rapid tech changes, and expressed intense emotions or pure sound exploration.\Impressionism vs. Expressionism - Impressionism (Debussy, Ravel) paints blurred “sound pictures,” soft tone colors, whole-tone scales. Expressionism (Schoenberg, Berg) dives into inner angst, uses atonality and twelve-tone rows.Chance (Aleatory) Music - John Cage let dice rolls, radio noise, or performer choice shape pieces, proving music can be unpredictable.Electronic Music - From theremin to synthesizer, composers like Stockhausen and later EDM artists used electricity and computers to create sounds impossible for acoustic instruments.