Zvuky Prahy / Sounds of Prague

Our current electrical and electronics technologies swamp us in an ocean of inaudible and invisible electromagnetic radiation and signals. It is relatively easy to make such signals hearable with cheap devices sold for recording telephone conversations. It’s amazing what can be found. This recording is of the audio frequency electromagnetic signals present inside a No 15 Prague tram as it travels from one stop to the next. The rise and fall of the tones roughly correspond to the speeding or slowing of the tram.