Considering the extent of Boris Karloff's presence on radio, beginning in 1938 in Hollywood On The Air and running another twenty five years and including over 800 appearances, it's surprising that this aspect of his career has not been given more attention. He could be heard regularly throughout the 1940's and 1950's in programs ranging from variety to comedy to suspense to horror. Especially horror.
And the radio horror program in which Boris Karloff could be heard most frequently was Inner Sanctum.
While Lights Out took its horror seriously enough to issue audience warnings, Inner Sanctum epitomized the campiness of radio horror. An odd combination of melodrama, horror and comedy, the show opened and closed to the sound of a creaking door: the door to the inner sanctum. The story goes that the program's director, Himan Brown, got the idea from a door in the studio's basement that "squeaked like Hell." Listeners were then greeted by the narrator, called Raymond in the show's early years, whose ghoulish humour, bad puns, and occasional banter with the show's sponsor lightened the mood regardless of the seriousness or creepiness of the episode. And many episodes were indeed creepy, despite Raymond's presence.
But apparently not creepy enough for Boris Karloff. Karloff appeared often in Inner Sanctum. During the first season, he was practically a regular, appearing in 15 episodes. When the network expressed concern about the level of horror and gore heard in the program, Karloff objected. He wanted more gore. He felt that his ". . . public expected it."
He didn't find any gore in the "The Wailing Wall", however. Instead, Karloff portrays Gabriel Hornell, a man who remains strangely attached to his old house. . .
(via Internet Archive)