Why is there a sound similar to electromagnetic interference in the room?

Electromagnetic waves are inaudible. For example, if there is no wind, even if you put your ears on the high-voltage line, you can't hear the sound. And the buzz I usually hear is the vibration caused by current and mechanical vibration. For example, the ballast of traditional fluorescent lamp, due to long time or factors such as thermal expansion and cold contraction, causes the internal tightness to vibrate at the frequency of 50 Hz, which causes us to hear the illusion of current sound. What you hear is also caused by the vibration of an electrical device and current. The elimination method can be adopted, that is, the culprit can be found every time a household appliance is disconnected. Generally (generally) the culprit will be emotional, such as household appliances with transformers.