Monday, June 18, 2012

Music Evolution and the "Loudness War"

Has music really changed over the past 50 years? Ask anyone who grew up with the Beatles, Elvis or even disco, and you'll hear a resounding 'yes.'

But a group of Spanish physicists wanted to mathematically measure the evolution of popular music over the past 50 years, just to be sure. Somewhat surprisingly, they found that music hasn't really changed that much on a fundamental, quantifiable level, according to their analysis of a million song dataset.

Nonetheless, the researchers did find three key trends in pitch, timbre (or tone quality), and loudness that may help explain the qualitative evolution of music. In particular, they found conflicting evidence of the "loudness war" among recording studios over the past few years – an apparent race for louder music at the expense of quality, according to critics.



The researchers took data from The Million Song Dataset, which includes sound information for a million contemporary pop songs, but none of the audio. The dataset provides song features including data about the song's pitch, timbre and loudness – the three factors that the researchers investigated.

First, the team analyzed the scientific backbone for the various pitches we hear in music: frequencies. According to the physicists, these frequencies are becoming more uniform with time.

Increasingly, the scientists observed "less variety in pitch transitions," in recent years, much to the dismay of non-conforming hipsters everywhere. To be fair, the Million Song Dataset likely left out a substantial selection of modern day music, which may include non-conformist pitch transitions.

But the scientists found the same trend in conformity for the dataset's timbre. Timbre, or tone quality, is what allows us to differentiate between different sounds such as vocals, percussion, and guitars. Scientists can quantify timbre by looking at the shape of a song's waveform.

Is The "Loudness War" Hurting Music?

While both timbre and pitch appeared to conform over time, songs have also become increasingly loud. Especially over the past few years, music critics and fans have complained about overly compressed songs that are recorded to be louder than ever. Critics claim that this compression for the sake of loudness has sacrificed music quality.

Anecdotal evidence abounds for this transition to louder music, but the Spanish researchers now have scientific evidence of this trend. But there was something important that the researchers did not find.

According to their paper, the "topology of loudness transitions is maintained," over time. The team didn't find evidence that the loudness race was negatively altering the volume dyanmics within the songs – the changes in volume that make certain parts of a song more distinct. "Loudness war" critics often cite altered volume dynamics as a key factor that degrades music quality

Perhaps there's something else that the scientists overlooked that could explain the supposed drop in sound quality. Or maybe the "loudness war" is overblown. You can decide for yourself by comparing the audio contained in the video below.



The researchers did note, however, that the continuing loudness race could potentially lead to poorer sound quality in the future, partly because of the restrictions of digital media.

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