Description: Electronic hum or buzz, around 50 Hz frequency

Description: Electromagnetic noise, hum and whine

Description: Electromagnetic noise, hum and buzz

Description: Electromagnetic noise, hum and buzz

Description: Electromagnetic noise, pulses and buzz

Description: Electromagnetic noise, hum and buzz

Description: Electromagnetic noise, hum and buzz

Description: Electromagnetic noise, hum and whine

Description: Electromagnetic noise and random overtones

Description: Electromagnetic noise, repeating rising note