Abstract: A signal conditioning system is disclosed for modifying the dynamic range of an electrical input signal. The system comprises gain control means for controlling the gain of the input signal as a function of a gain control signal, and control signal generating means for generating the gain control signal. In accordance with one aspect of the present invention the control signal generating means comprises (1) means for generating a first signal as a function of the amplitude of the input signal, and (2) means responsive to the first signal for generating the gain control signal as a function of only those portions of one polarity of the time derivative of the first signal. In accordance with another aspect of the present invention means are provided for substantially lengthening and/or linearizing the release behavior of the control signal waveform applied as the control signal input signal to the gain control means.