A process evaluation was applied to the development and implementation of a receptive music therapy tool, with a view to promoting evidence-based practice via clear linkage from theory to practice. This music tool was required for a research project in the noisy emergency department (ED) of a large urban hospital. The process evaluation focuses on questions about the suitability, planning, application, and effectiveness of this tool used within the research project protocol. The music tool intervention was applied to fifteen selected patients who received a choice of four genre-based relaxation playlists (GRP) over a two-hour period via headphones and MP3 players. The process evaluation method utilized data sources including key informant interactive interviews, observational data, reflective practices, patient feedback and an independent music review. Responses from patients (aged 23-91 years) indicated that most patients listened to multiple genres and most patients (n=14) indicated that the music made them feel better, thereby indicating suitability and effectiveness. Independent music reviewers confirmed that the music playlists contained relaxing musical elements, based on established music therapy criteria. This project was innovative in clearly documenting a music tool development process (GRP) and in turn applying a process evaluation to systematically review both the development and implementation of the tool. In doing so, linkage from theory to practice was established, contributing to understandings about music for relaxation in healthcare.