Primary sources provide first-hand testimony or direct evidence concerning a topic under investigation. They are created by witnesses or recorders who experienced the events or conditions being documented. Often these sources are created at the time when the events or conditions are occurring, but primary sources can also include autobiographies, memoirs, and oral histories recorded later. Primary sources are characterized by their content, regardless of whether they are available in original format, in microfilm/microfiche, in digital format, or in published format.
Thanks to the Yale University Library for this description.
Secondary sources are works that interpret, analyze, and discuss the evidence provided by primary sources (e.g., scholarly books and articles). The secondary sources are generally a second-hand account or observation at least one step removed from the event, i.e., accounts written after the fact by people not present when an event took place. Such sources are second-hand interpretations of what occurred.
*Some of the above material is used with permission from the University of Pittsburgh Library's research guide on Primary Sources
Primary sources for music may include
Secondary Sources may Include
Music: score, sound recording, contemporary review, letter, personal account by composer or musician