Psychoacoustics is an interdisciplinary science focusing on the psychological perception of sound. It establishes relationships between objective physical parameters (sound pressure level, frequency, ear anatomy…) and subjective hearing impressions (pleasantness, pitch, perceived volume…).
Different psychoacoustic metrics such as loudness, sharpness, tonality and roughness provide a linear representation of human hearing perception. Each metric measure one specific sound parameter: level for roughness, amount of high-frequency components for sharpness, etc. However human auditory perception is global and takes into account all different parameters according to complex auditory phenomena. It is thus needed to combine the different metrics within a global sound quality estimation to get a good estimation of the human ear perception. It is done with hearing tests following rigorous protocols with a sufficient number of normal-hearing subjects.