Abstract: To provide for response of audio reproduction equipment with the full dynamic level range, for example of music, intended by a composer, although radio signals transmitted have been compressed to reduce the signal-noise level, an expander circuit (20a, 20b, 20c) is activated based on ambient noise level conditions as sensed, for example, by a microphone (12) which determines the ambient noise level. If the ambient noise level, for example within certain frequency bands, as selected by filters (32a, 32b, 32c) is low, so that the full dynamic range (difference between low volume and high volume passages) can be reproduced, a range expander (20a, 20b, 20c) is controlled, for example within selected frequency bands, to reproduce the respective frequencies, or the overall signal, with a dynamic range greater than that of the received compressed signal and, preferably, corresponding to the dynamic range of the original signal which was then compressed for transmission.

Abstract: In an environment of acoustic noise, such as a car radio playing in traffic or engine noise, both the volume (AGC) and dynamic range (Compression) of the audio amplifier are controlled by a local ambient acoustic noise sensor, such that gain is increased and dynamic range decreased simultaneously with increased ambient noise.