An Investigation into the Sonic Signature of Three Classic Dynamic Range Compressors

Dynamic range compression (DRC) is a much-used process in music production. Traditionally the process was implemented in order to control the dynamic range of program material to minimize the potential of overloading recording devices. However, over time DRC became a process that was applied more as a creative effect and less as a preventative measure. In a professional recording environment it is not uncommon for engineers to have access to several different types of DRC unit, each with their own purportedly unique sonic signature. This paper investigates the differences between three popular vintage dynamic range compressors by conducting a number of measurements on the devices. The compressors were tested using: THD measurements, tone bursts and objective analysis of music-based material using spectrum analysis and audio feature extraction.