The researchers used a dataset of 464,411 music recordings to analyse what has changed – and what has stayed the same – over the past half-century of song. "Many of [music's] patterns and metrics have been consistently stable for [this] period," they wrote. "However, we prove important changes or trends related to the restriction of pitch transitions, the homogenisation of the timbral palette, and the growing loudness levels."The research team also confirmed the existence of the “Loudness War”, the trend to crush dynamic range out of recordings in favour of music that sounds ass-kickingly loud enough to compete with the other ass-kickingly loud tracks on the market, and whose sonogram looks less like a waveform and more like an angry, ragged-edged rectangle.
Meanwhile, another study of recorded music over the same period has found that pop music has been becoming less jauntily upbeat and more sombre or emotionally ambiguous:
Schellenberg and von Scheve found that the proportion of songs recorded in minor-mode has increased, doubling over the last fifty years. The proportion of slow tempo hits has also increased linearly, reaching a peak in the 90s. There's also been a decrease in unambiguously happy-sounding songs and an increase in emotionally ambiguous songs.
Unambiguously happy songs like Abba's Waterloo sound, to today's ears, "naive and slightly juvenile", the researchers noted. And whilst modern songs in a similar style, such as Aqua's Barbie Girl, can still enjoy huge commercial success, they're usually seen as a guilty pleasure and savaged by critics.(Or, to quote the Pet Shop Boys, “make sure you're always frowning; it shows the world that you've got substance and depth”.)