What is metal detector “autotune” or automatic tuning? Not automatic ground balancing or automatic ground tracking. Autotune is something so common now it is taken for granted, but it is a key feature when considering how detectors work, especially those designed to work with a faint threshold sound, like most nugget detectors. Prior to the 1980's most detectors had to be ''tuned''. You held them at a fixed height over the ground and manipulated a ''tuner'' until you got a bare threshold so