An improved system for compressing or expanding the dynamic range of an electrical input signal of the type which includes a variable gain device for controlling the gain of the input signal and a circuit for generating a control signal for the variable gain device including a rectifier for producing responsively to the input signal a DC signal which substantially follows dynamic variations of the input signal. The improvement resides in the provision in the control signal generating circuit of a network of at least three signal paths having a common input terminal connected to receive the DC signal and a common output terminal connected to the variable gain device for coupling a control signal thereto, which signal paths have differing time constants and are automatically selectable as a function of the rate and amount of change in amplitude of the DC signal.