Original cast: the premiere or original cast of the production. (Original Broadway Cast; original London cast; original Toronto cast, etc) and can include revivals as well as first productions. Studio cast: assembled by a record company. In the early days the studio cast singers were often lesser known performers with good singing voices, usually joined by one fairly well known star. Mary Martin made a number of studio cast recordings for Columbia in the early 1950s including Babes in Arms, Girl Crazy and Anything Goes. More recent studio albums have tended to be note-complete recreations of the original orchestrations often with opera singers taking the leads such as EMI's recordings of Brigadoon and Show Boat.   Wikipedia