Technology has had a profound impact on how we listen to, create, and perform music. Among the Library of Congress' collections are wax cylinders, photographs, manuscripts, recordings, and more that document the evolution of sound technologies. Students can use these sources to assist them as they respond to and analyze music in all its historical and technological contexts. To support students in understanding how the recording technology used to produce sound informs the listeners' response to that sound, teachers may guide them to explore the digitized resources at the Library of Congress. Here, they can research the history of music machines from their inception and listen to many of the first recordings of sound. Students can observe how as music began to be recorded, certain elements, such as repetition, became less common, and the complexity of the music increased.