It's official - science has essentially proven, with a study, that Pop music is indeed both getting louder and diminishing in variety. A team of researchers in Spain headed by artificial intelligence specialist Joan Serra have run a set of songs from the last 50 years through a set of complex algorithms that have yielded the following results: Pop songs on the whole have become more bland in terms of chords, melodies, and types of sound, and are intrinsically louder to boot than they've ever been before.
With a gigantic archive known as the Million Song Dataset, the research group took audio and lyrical content and broke it down into crunchable data. From there they checked out how high the intrinsic loudness of the tracks were, for starters. Intrinsic Loudness can be explained as the common sound level that's present in a song or a whole set of songs.
In the book "Mastering Audio: The Art and Science" by Bob Katz and Robert A Katz, they speak about this situation in short:
"In the days of the LP, the variation in intrinsic loudness of pop recordings was much more consistent, perhaps within as little as 4 gB. Even at the peak of the vinyl loudness race. I cloud put on a Simon and Garfunkel LP, or even a Led Zeppelin, and follow that with an audiophile direct-to-disk recording, barely having to adjust the monitor control to satisfy my ears.
In the earliest days of the compact disc, before the digital loudness race began, many master engineers would dub analog tabs with o VU set to -20 dBFS, and leave the headroom to the natural crest factor of the recording. It was not thought necessary to peak to full scale, and so the intrinsic loudness of early pop CDs was much more consistent. However, the inventors of the digital system abandoned the VU meter, which opened Pandora's box." - Mastering Audio: The Art and Science
A Volume Unit meter (VU meter) is a device that shows the signal level of the audio you're playing. Most often, VU meters are used just for the lovely look of having your meters jumping around at peak - but they certainly can be useful in situations such as these to show how terribly loud everything has gotten.
"We found evidence of a progressive homogenization of the musical discourse. In particular, we obtained numerical indicators that the diversity of transitions between note combinations - roughly speaking chords plus melodies - has consistently diminished in the last 50 years." - Serra
Serra and her team also spoke with Rueters noting that the timbre palette in today's Pop tunes has become less diverse over time. Louder and less diverse music for all, that's what music is evolving into for the masses. Do your part and break out the vinyl, ladies and gentlemen!