To make the fake city recording, the unnamed creators would have had to gather these sound effect actors around a giant horn. To "mix" the sound, people would have actually been distributed and moved through the room.
As they made noise, the acoustic horn would funnel the vibrations down to a diaphragm, which would move a stylus up and down, creating grooves of different depths. The sound was being physically etched into the wax -- carved like letters into a tree -- for later playback.
And that's the problem: the range of sound that could be picked up by the acoustic horn and then etched was narrow. The devices were also finicky and heavy and awkward.
Even recording musicians, who were trained to direct their noises into an acoustic horn, was incredibly difficult. Here's Mark Katz describing the recording booth in his 2004 book Capturing Sound: how technology has changed music:
"The room was usually small, windowless, overheated, and empty, save for a large megaphone-shaped horn and a small red light or perhaps a buzzer attached to one wall. During the performance, musicians had to be careful not to make extraneous, recordable noises, not to gesture unduly (lest they knock the equipment over), and not to sing or play too loudly or softly."
Only certain types of musical instruments recorded well. Horns were great; violins not so much. Certain singers recorded well; the best learned to move their heads and bodies around the horn to create the right kinds of effects. Women's voices, particularly on the higher end, were hard to pick up, too, as pointed out by historian Lisa Gitelman, into the late 1890s.
"The Boswell Company of Chicago offered its 'high grade original' records in 1898 with the assurance that 'At last we have succeeded in making a true Record of a Lady's voice. No squeak, no blast; but natural, clear, and human,'" she wrote. "The Bettini Phonograph Laboratory in New York similarly claimed "The only diaphragms that successfully record and reproduce female voices."
Obviously, these recording setups were not made for fieldwork. You couldn't just take them outside and flip a switch. It wasn't until the 1920s, Barton said, that microphones were developed. They could electronically amplify sounds and enabled the recording of soundscapes. From the very first, film could be used as a documentary device, easily recording ambient scenes. Sound recording, on the other hand, required performance for its first 50 years.
This timeline, when you match it up with other technological changes, has some very important consequences.
There will always be a large gap between our visual and audio historical records. Decades when we can see our places, but not hear them. We will never know what New York, Los Angeles, or any other city sounded like before the automobile hit the streets and electricity was commonplace.
Some things, like what it sounded like for a million Americans to live together without internal combustion engines on wheels, can be lost forever.
Images: 1. MadridSoundscapes.org 2. Library of Congress. 3. New York Public Library.