The New Aesthetic

Electrical network frequency (ENF) analysis is a forensic science technique for validating audio recordings by comparing frequency changes in background mains hum in the recording with long-term high-precision historical records of mains frequency changes from a database. In effect the mains hum signal is treated as if it were a time-dependent digital watermark that can help identify when the recording was created, and help detect any edits in the recording.[1][2][3] Historical records of main frequency changes are kept on record f.e. by police in the german federal state of Bavaria since 2010[4].