Linear Dynamic Range Reduction of Musical Audio Using an Allpass Filter Chain

The reduction of signal dynamic range through limiting of peak amplitude is an important process in modern audio signal processing, mainly for loudness maximisation. Traditional processes are non-linear, and can produce significant distortion of the processed signal. In this paper we present a new linear technique that reduces the peak amplitude of transient signals using golden ratio allpass filters. The system is applied to test signals consisting of both isolated musical sounds and mixed musical audio. The average reduction of the peak amplitude of the musical passages considered is 2.5 dB. The system can be applied alongside non-linear methods, to reduce the distortion associated with a particular reduction in peak amplitude.