Apparatus and Method for Enhancing an Audio Signal, Sound Enhancing System

An apparatus for enhancing an audio signal comprises a signal processor for processing the audio signal in order to reduce or eliminate transient and tonal portions of the processed signal and a decorrelator for generating a first decorrelated signal and a second decorrelated signal from the processed signal. The apparatus further comprises a combiner for weightedly combining the first and the second decorrelated signal and the audio signal or a signal derived from the audio signal by coherence enhancement using time variant weighting factors and to obtain a two-channel audio signal. The apparatus further comprises a controller for controlling the time variant weighting factors by analyzing the audio signal so that different portions of the audio signal are multiplied by different weighting factors and the two-channel audio signal has a time variant degree of decorrelation