I ended my afternoon watching BEHIND THAT CURTAIN, the first Fox film that featured Charlie Chan. Truth to tell it's not a mystery and Chan's only on screen in the last few minutes.
It's a lousy movie, the dreariest kind of melodrama with a heroine whose voice quavers with every line since her "honor" is at stake. Being such an early talky, everyone (except star Warner Baxter) speaks very slowly and distinctly for the microphone which makes a movie that should have run 70 minutes into a 90 minute film (and it seems even longer than that).
Lo and behold, there's Boris Karloff acting the part of a servant in the second half of the film. His voice, of course, records beautifully.