In the field of technology and innovation management, innovation evolution historically has enjoyed high level of attention. The theories such as dominant design, technological guidepost have been used to describe the evolution nature of the innovations. However, various innovations still demonstrate developments outside the descriptions of existing theory. We hope to address this issue by conducting a data rich detailed longitudinal study on an innovation to see whether existing theories, more specifically the dominant design theory, can describe the evolution of the innovation. We collected detailed information (especially on product level) of the portable MP3 player innovation in U.S. between 1998 and 2012 from various secondary sources including industry magazines, popular press, and company websites. Using this information, we try to understand the convergence nature of the innovation and test whether the dominant design theory can explain the evolution of the innovation well or how it is different from the theory.