Since they have low power and after radiation they decay very quickly. Vibrations in audio frequency are relatively slow vibrations. Almost no sound frequency electromagnetic waves are emitted. To transmit such waves over long distances, it is first necessary to convert them into high-frequency oscillations, which is a modulation process, as a result of which a low-frequency signal is superimposed on a high-frequency one.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.