Repeat recreational exposure to loud music is a key risk factor for noise-induced hearing loss (NIHL) and represents a major public health concern.1 The World Health Organization estimates that 50% of individuals aged 12–35 in developed nations are regularly exposed to unsafe levels of sound from personal music players, with up to 1.1 billion youth worldwide at risk of consequent NIHL.2
While prior studies have established the deleterious effects of high music volume expressed in decibels of sound pressure level (dBSPL),3 this end-product perceived by the human ear is a composite of several inter-related factors leading to the perception of loudness, including user-controlled volume settings and the intrinsic sound intensity of the sound media itself. In acoustical engineering, the latter may be expressed as decibels relative to full scale (dBFS), an absolute measurement of instantaneous energy which, when all other factors (such as user-defined volume levels) are held equal, is correlated to dBSPL.4
Few studies have examined the evolution of the underlying audio engineering of music, a systemic factor which may contribute to NIHL. As industry trends may have progressively accentuated popular music sound intensity over time, a phenomenon generally referred to as the “loudness wars,”5 we undertook a big data analysis of the evolution of such musical sound intensity, as measured in dBFS, to quantitatively assess temporal trends in the loudness of popular music released over the past six decades.