Asymptotic
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From what I'd been reading, Reginald Fessenden devised the first audio detector circa 1902. As @sophiecentaur said, coherers and Marconi's magnetic detector aren't rectifiers, and are incapable of demodulation.
https://en.wikipedia.org/wiki/Electrolytic_detector
https://en.wikipedia.org/wiki/Electrolytic_detector