Enormous megaphone from silent film era - photo

[Jon]

Directing extras in the 1922 silent film Robin Hood. That's director Allen Dwan on the far right in the hat, and I think that's the lead Douglas Fairbanks standing at the middle of the megaphone. Microphone technology had been invented by 1922, but I believe it was not yet as effective as a simple giant cone. This makes me curious about the limits of using a megaphone to amplify sound.