Final answer:
The 20th century saw a radical transformation in music composition and audience listening habits due to advances in communication technology, which led to the global spread of new musical styles and the creation of a shared mass culture.
Step-by-step explanation:
In the 20th century, the explosion of new communication technologies such as radio, television, and the internet dramatically reshaped both the creation and consumption of music. Increased means of communication gave composers and musicians the ability to reach global audiences, pushing them to experiment with new styles and forms, leading to movements such as modernism in music.
For audiences, these advances expanded listening choices well beyond local performances, allowing them to access a diverse range of music from different cultures and genres. This exposure led to both a greater demand for variety and a unification of cultural experiences as people across the world listened to the same songs and watched the same films. The development of mass media technologies, particularly motion pictures, and radio, created a new shared culture by broadcasting the same content to listeners and viewers regardless of their physical location. Additionally, the introduction of multimodal communication, which includes sound, images, text, and movement, added layers of complexity to how people expressed themselves and interacted with content.