This is where Jem and the Holograms record the songs for their albums, atleast sometimes, since it's expensive to get studio time here, and they do have recording studios in Starlight Music and Starlight Mansion aswell. The Starlight Recording Studio only ever appears in one episode, and looks very similar to Starlight Music.

On the building where it says Starlight Recording Studio, inside the star it also says 8603 which to me seems like March 1986, which is probably when the episode was animated.
8603	Studio
The blonde studioman here is called Tim.
This is where they keep the master tapes after they record it.