A sound recording (sometimes referred to as the "master" version) is a recorded performance of a composition.  

Although a musical work is embodied within a sound recording, a musical work and a sound recording are legally separate. 

There may be multiple sound recordings of a single musical work, including re-records, edits, remixes, and covers. For example, Dolly Parton wrote the musical work "I Will Always Love You," but both Dolly Parton and Whitney Houston have sound recordings of that work.