Mel White, the name of the actor hired to perform in Frasier's radio play, is a reference to legendary voice actor Mel Blanc ("blanc" being the French word for white). White is described as "the man of a thousand voices," an epithet usually associated with Blanc.
In the closing credits sequence, Noel (Patrick Kerr) assumes a broadcast stance, where he extended the script pages on the far side of the microphone. This is the actual way that radio workers stand so that no rustling of paper can be picked up by the microphone.
Frasier reminds his audience to listen to the upcoming radio drama "Nightmare Inn" by adopting an ominous voice and saying, "You'll never know what's lurking in the shadows..." This is a nod to the 1930s radio drama "The Shadow," where actor Frank Readick would intone the show's introduction in a similar manner: "Who knows what evil lurks in the hearts of men? The Shadow knows!"
Frasier's play celebrates KACL's 50th anniversary, which means the station started in 1947.