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Is Pop Music Evolving, or Is It Just Getting Louder?

The views expressed are those of the author and are not necessarily those of Scientific American.

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Classic record jukebox

Joe Mabel/Wikimedia Commons

Music just ain’t what it used to be. At least, that’s the stereotypical lament of each receding generation of music listeners. It’s also one way to read a new study on the evolution of pop music in the past half-century.

A group of researchers undertook a quantitative analysis of nearly half a million songs to look for widespread changes in music’s character over the years. The findings, published online July 26 in Scientific Reports, show that some trends do emerge over the decades—none of them necessarily good. (Scientific American and Scientific Reports are both parts of Nature Publishing Group.)

The researchers based their analysis on the Million Song Dataset, a publicly available 280-gigabyte file that provides a sort of background sketch—name, duration, tempo, and so on—of songs from nearly 45,000 artists. Of the million songs therein, 464,411 came out between 1955 and 2010 and include data on both the sonic characteristics and the year of release.

Joan Serrà, a postdoctoral scholar at the Artificial Intelligence Research Institute of the Spanish National Research Council in Barcelona, and his colleagues examined three aspects of those songs: timbre (which “accounts for the sound color, texture, or tone quality,” according to Serrà and his colleagues); pitch (which “roughly corresponds to the harmonic content of the piece, including its chords, melody, and tonal arrangements”); and loudness (more on that below).

After peaking in the 1960s, timbral variety has been in steady decline to the present day, the researchers found. That implies a homogenization of the overall timbral palette, which could point to less diversity in instrumentation and recording techniques. Similarly, the pitch content of music has shriveled somewhat. The basic pitch vocabulary has remained unchanged—the same notes and chords that were popular in decades past are popular today—but the syntax has become more restricted. Musicians today seem to be less adventurous in moving from one chord or note to another, instead following the paths well-trod by their predecessors and contemporaries.

Finally, it comes as no surprise that music has gotten louder. A piece of music’s loudness is an intrinsic characteristic of the recording, not to be confused with the listener-controlled volume. “Basically, the audio signal, when recorded and stored, is physically bounded to be between certain values (+1 and –1 volts in original recording systems),” Serrà explained in an email. “You can record signals fluctuating between –0.2 and +0.2 or between –0.6 and +0.6 (positive and negative fluctuations are necessary to make the loudspeaker membrane move). That’s the intrinsic loudness level we’re talking about.”

For years audiophiles have decried the “loudness wars”—the gradual upping of recorded music’s loudness over time, in an apparent effort to grab listeners’ attention. Loudness comes at the expense of dynamic range—in very broad terms, when the whole song is loud, nothing within it stands out as being exclamatory or punchy. (This two-minute YouTube video does a great job of demonstrating how excessive loudness saps richness and depth from a recording.) Indeed, Serrà and his colleagues found that the loudness of recorded music is increasing by about one decibel every eight years.

It’s an interesting study, and it seems to support the popular anecdotal observation that pop music of yore was better, or at least more varied, than today’s top-40 stuff. (A recent study also found that song lyrics are darker and more self-focused than they used to be.) But I did wonder if there was a selection bias in play here. The Million Song Dataset, huge as it is, may not provide a representative slice of pop music, especially for old songs. Its contents are heavily weighted to modern music: the database contains only 2,650 songs released between 1955 and 1959, but nearly two orders of magnitude more—177,808 songs—released between 2005 and 2009. That’s because it draws on what’s popular now, as well as what has been digitized and made available for download. And the songs of yesteryear that people enjoy today (as oldies) may not be the same ones that people enjoyed when those songs first came out.

Let’s assume for the moment that the trends identified in the new study—especially the homogenous timbres and restricted pitch sequences—are bad. Then the rare song that bucked those trends, offering up novel melodies and sonic textures, would stand out as being good. Therefore, that song would have a better chance than its contemporaries of surviving the test of time—that is, a better chance of finding itself digitized and widely played some 50 years after its release, thereby boosting its odds of inclusion in the Million Song Dataset. Meanwhile, the blander tunes of decades past would have faded into analog obscurity. The relatively few old songs in such a database, then, would tend to be more sonically interesting than the average song of today, and any analysis comparing old songs to new would likely reflect that. So I wondered if part of what this study is telling us is that bland music can fool us, but not for long.

Serrà acknowledged in an email that a bias due to the “test of time” effect is possible but argued that its influence should be small. For instance, he noted, the long-term patterns and trends that he and his colleagues identified also hold over relatively short—and relatively recent—time periods (say, 1997 to 2007), where the “test of time” effect should be minimal. “The same happens with close and not-so-recent time periods (e.g., 1960 and 1968), where both years could partly incorporate such an effect,” he wrote. “Since the trend is consistent in short time spans where you assume the ‘test of time’ bias is minimal and, furthermore, the trend is also consistent for longer time spans, we can assume it is a general trend and, thus, that the ‘test of time’ effect is really small.”

About the Author: John Matson is an associate editor at Scientific American focusing on space, physics and mathematics. Follow on Twitter @jmtsn.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. jtdwyer 1:39 am 07/27/2012

    Perhaps it should also be noted that music was once played most often for mixed gender group activities and social events – dances, parties, etc., whereas it is now very often played for private individual listening (providing personal isolation from external events), through headphones.

    ‘Music’ is now often played in ‘public’ on powerful car audio systems for (almost exclusively male) assertive/aggressive expression or competitive purposes, where loudness may be the most important objective.

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  2. 2. kidprofessor 12:57 pm 07/27/2012

    Melodic variety has decreased, but rhythmic variety may have increased. Dynamics has decreased and timbre variety has decreased, but perhaps the number of individual sounds layered into a modern recording may have increased. The latter may be difficult to measure, but the former should not present a problem.

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  3. 3. BcdErick 2:26 am 07/28/2012

    I’m just trying to be polite, but really. This is both endearing and embarrassing. You folks are just getting old. There is no cure. Every generation says this of the previous. And when you get older loud noise can be physically bothersome. There is no solution other than to stay away from loud music if it bothers you.

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  4. 4. johnwbyrd 3:45 pm 07/28/2012

    This article, and the underlying research, are both nearly harmless nonsense.

    While there is plenty of evidence indicating that equal loudness has increased significantly since computers began mixing music (q.v. Fletcher-Munson curves), there’s zero evidence that a Fourier transform can extract artistic qualities such as “timbre” from a public domain recording.

    Just reliably picking out a melody from a recording, via an automated process, is next to impossible. One recent academic paper was overjoyed to report ~60% accuracy in this regard, and that’s only for a single melody line. Good luck acquiring meaningful “pitch” and “timbre” data for half a million recordings of every genre, recorded with every conceivable combination of equipment, with every conceivable frequency response.

    Given this highly randomized data set, the authors claim to have found “codewords” which are representative of musical styles and periods. The authors acknowledge the novelty of the codeword idea, and have provided no evidence that codewords actually exist, or provide any indication that codewords are useful for psychoacoustic analysis. No composer living or dead has ever considered a codeword while writing a song.

    Unfortunately, this article is only mostly harmless. Friedrich Schenker’s school of tonal analysis tried expressly to prove the superiority of German music through complicated tonal analysis. Likewise, the author’s claims of “blockage” and “no-evolution” of modern music should be interpreted entirely as the opinions of the authors and not given any further countenance.

    While bemoaning that the current generation’s music is inferior to the older generation’s music is a great American pastime, there is nothing minimally Scientific about it, and the editors would do best to avoid suggesting otherwise.

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  5. 5. nulldevice 11:57 am 08/1/2012

    There’s a lot about this study that bothers me. Yes, we can say that music has gotten a lot louder over fifty years, and everyone will be quick to blame the loudness wars. That’s true to an extent, but just between say, 1955 and 1975, before the loudness race really kicked into high gear, there was a huge increase in loudness there too – not becasue of engineers and producers cranking out all the dynmaic range, but simply because of things like increased use of condenser microphones instead of ribbons, better compressors, and even just multitracking of bands.

    But more importantly, this focuses on a nebulous style of music known as “pop.” The very definition of pop music has varied a stunning amount in 50 years. In the past 20 years alone, a lot of what might have been fallen under the rubric of “pop” in the 1970′s spun off into separate subgenres. There’s a lot of stuff out there that’s “popular” but isn’t exactly “pop.” In 1955, “pop” included a lot of nascent rock, R&B, even jazz. Now it’s narrowed down to a very specific sort of R&B and dance-influenced style of music. Ironically, “pop” itself has become a subgenre. One that gets a lot of radio play, sure, but a narrowly-defined selection for sure. That makes it pretty meaningless to try and generalize about all music based on a study of “pop.”

    The chordal thing..well, it makes sense, but again it’s pretty hard to make a values judgement about anything based simply on the fact that there are fewer chord changes in an average pop song. In the late 70′s, minimalism started creeping into pop music (e.g. Kraftwerk) and eventually it became the dominant musical form in dance music (techno, trance, house, even hip-hop have a lineage that can be at least partially traced back through Stockhausen and Reich). A lot of modern pop is heavily dance-music influenced, so one would expect fewer chord changes in something with a minimalist heritage. Not that any of it’s a straight-up Phillip Glass track or anything, but you can hear the influence pretty easily.

    Overall there’s a lot of Get Off My Lawn in the study, and that sort of bugs me. I’m old enough that I could jump aboard this train and nobody would expect different, but come on, cloaking this in, to borrow from Dolby and Pyke, “SCIENCE!” just rubs me the wrong way.

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  6. 6. Graphic Equaliser 10:12 am 08/16/2012

    Music has definitely lost its complexity over time. But that’s not all – it has also lost nearly all of its political content. All people sing about nowadays are the trials and tribulations of attempting to breed! As for me, I produce my own music with chords formed from an almost infinite variety of notes (not just 8 to an octave!) – hear it at

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  7. 7. upload70 8:44 am 10/5/2012

    I really think the music of years gone by is far better than today’s.

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