Frequency Analyzers have been around nearly as long as oscilloscopes. Basically they’ll sweep a band pass filter and plot amplitude vs frequency on the screen.

Frequency Analyzers have been around nearly as long as oscilloscopes. Basically they’ll sweep a band pass filter and plot amplitude vs frequency on the screen. Also - you can reproduce a sound by the frequency domain IF you look at the time progression of it. Some Hammond Organs intentionally had a percussion control where the 3nd or 3rd harmonic would decay over time, giving the instrument timbre a bit of a pop.