What is the most appropriate relationship to use on recordings for ensembles that include both vocals and supporting instruments (the recording is vocals and music)? For example, Ricercar Consort. The “performer” relationship is a nice catch-all; however, an argument could be made for using “orchestra” and “vocals” as two separate entries.
Good question. I would follow the CD cover: add “chorus” and “orchestra” (or “vocals” and “instruments” for solo performers) if they are credited separately on the cover, or just an “orchestra” if it is credited as a single entity. Common practice also plays a role. For example, chorus and orchestra of the Moscow’s Bolshoi Theater are traditionally credited separately (example).