Abstract: An audio signal monitoring system is disclosed, which provides simultaneous visual indication of instantaneous peaks of a monitored audio signal and of peaks which are sustained for a predetermined period of time. A high impedance buffer combined with a precision full wave rectifier receives the monitored audio signal and generates a corresponding d.c. signal which varies according to the amplitude level of the audio signal. A peak detection circuit is connected to receive the d.c. signal and drive a meter movement to indicate instantaneous peaks in the audio signal level. A comparator circuit is connected to receive the d.c. signal and compare the d.c. signal with several predetermined threshold levels. Separate indicators corresponding to each threshold level are selectively energized by the comparator circuit whenever the d.c. signal exceeds the respective threshold levels for a sustained period of time.