The effect of dynamic range compression on the psychoacoustic quality and loudness of commercial music

This thesis studied the effects of Dynamic Range Compression (DRC) on audio signals. This research devised and tested production strategies to improve and reduce the impact of DRC on signals, verified by listener preference. The nonlinear characteristics of DRC, combined with the interaction of signals once summed, are likely to produce Intermodulation Distortion (IMD), which is unpleasant to hear. In a bid to reduce these nonlinear effects, the point of application, along with the magnitude and type of DRC used in the mixing signal chain was experimented with, reducing the number of signals interacting while under DRC. The different DRC configurations were used to examine fatigue and listener preference. Listening preference tests from this research demonstrate listener inclination for compression being applied to sums of fewer sources, as opposed to compressing signals formed from many sources or subgroups, as is the traditional method for music production. Comparative quantitative analysis of simple and compound signal structures under DRC showed some effects from nonlinearity to be the realignment of harmonic signal structures, alteration of instruments’ amplitudes relative to one another, reduction of spectral and temporal clarity, and rearranged dynamic variances related to the rhythmic structure of musical signals. This research shows that decreasing the number of signals interacting under DRC, utilising moderate DRC and applying compression rather than limiting type DRC can reduce the effects of intermodulation distortion, and improve listener enjoyment. Listening tests employing a temporal estimation task showed that heavy DRC signals might induce fatigue, though the results were inconclusive.