* Time period: Katy Perry is a contemporary musician, while Beethoven lived in the late 18th and early 19th centuries. This difference in time period has a significant impact on their music, as the styles and conventions of music have changed dramatically over the years.
* Genre: Katy Perry is a pop singer, while Beethoven was a classical composer. Pop music is typically characterized by its simple melodies, catchy hooks, and repetitive verses, while classical music is more complex and often features longer, more intricate compositions.
* Instrumentation: Katy Perry's music is typically created using electronic instruments and synthesizers, while Beethoven's music was written for acoustic instruments such as the piano, violin, and cello.
* Audience: Katy Perry's music is popular with a wide range of listeners, while Beethoven's music is typically appreciated by a more niche audience of classical music enthusiasts.