I stood under the transmission lines with my Olympus LS-7 recorder in NW Ohio to get the sound. According to a map I found online, the lines are indeed 765,000 volts phase to phase, four lines bundled for each phase. 765千伏輸電線路嗡嗡作響 聲道:2 類型:wav power、voltage、electrical、hum、high 功率、電壓、電動、哼、高 資料來源:freesound ( https://freesound.org )