Zotero is a wonderful, labor-saving tool for managing citations and generating notes and bibliographies. However, it does not yet handle citations for audio recordings well. Altering the item records can get your audio recording citations closer to the proper format, minimizing the amount of manual editing needed.
It is best to leave all the manual editing until the final edit, as any updates to your bibliography, notes, or Zotero records will over-write any manual edits.
