Increased levels of bass over time in popular music recordings and their relation to loudness

Abstract

The sound of recorded music changes over time, and can be captured by changes in audio features. Over the past decades, popular songs have shown clear increases in loudness (RMS energy), but far less attention has addressed whether this upward trend is more prevalent in specific frequency bands, such as the bass. Bass frequencies are especially important for movement induction and might offer competitive advantages of capturing attention and increasing engagement. Here, we examined the evolution of audio features, such as RMS energy and spectral fluctuations (changes in the audio signal’s frequency content) in 10 frequency bands from songs on the Billboard Hot 100 charts from 1955 - 2016. Over time, RMS energy increased and dynamic range decreased. The largest increases were found in the bass range: Spectral flux increased most strongly in the lowest frequency bands (0 - 100 Hz), and when controlling for overall RMS, only the lowest frequency bands showed an increase over time. The upward trend of bass could reflect changes in technology and style; but based on links between bass and movement, it is likely a widespread technique to increase engagement and contribute to chart success.