United States

What Mediumwave DX sounded like in 1933: this video posted by the Antique Wireless Association features clips recorded by a UK DXer that year of mediumwave stations from the U.S. as received at his location. He was recording to aluminum disc, a process that involved “embossing” rather than cutting, as with lacquer discs. The audio (and reception) quality is pretty amazing: 
Andy Robins, Kalamazoo, Michigan USA to WOR groups.io (2021-03-13)

More about this with same link:
James Niven, Austin TX, nrc-am gg via WOR groups.io (2021-03-13)