ased on a 1933 stage production billed as “The Play That Made Broadway Gasp,” it features an over-the-top performance by Mary Morris (repeating her stage role) as a domineering money-bags whose suppressed incestuous urges go into overdrive when her half-brother (Kent Taylor) brings a new bride (Venable) home to the family’s gloomy Fifth Avenue mansion. The title refers to a secret soundproofed chamber that the villainess uses to entrap her enemies. (Gene Siskel Film Center)

Overview from themoviedb.org