Turn on, turn off the appliance, low-frequency hum: Listen & Download Turn on, turn off the appliance, .mp3 Error! Change your browser, please! ⇓ Download Small electric motor ⚠ Switch ⚠ Electric sparks ⚠ Toggle switch, Small switch ⚠ Electricity, Current, discharge ⚠ Electrical discharge surge ⚠ Low frequency rumble ⚠ Button click ⚠ Movement, Low frequency electric drone ⚠ Electric transformer ⚠ Shoots an electric arc indoors ⚠ Jacob’s ladder, Electric discharges ⚠ ★★★★★