"The MIR Perspective on the Evolution of Dynamics in Mainstream Music"

This article by Deruty and Pachet presents a detailed analysis of the effect of the loudness war on the dynamics of commercial music.

"Understanding the evolution of mainstream music is of high interest for the music production industry. In this context, we argue that a MIR perspective may be used to highlight, in particular, relations between dynamics and various properties of mainstream music. We illustrate this claim with two results obtained from a diachronic analysis performed on 7200 tracks released between 1967 and 2014. This analysis suggests that 1) the so-called “loudness war” has peaked in 2007, and 2) its influence has been important enough to override the impact of genre on dynamics. In other words, dynamics in mainstream music are primarily related to a track’s year of release, rather than to its genre."

(I assume "MIR" stands for Music Information Retrieval.)

In their conclusion, they say:

"We have shown that the loudness war has peaked in 2007, and that a return to pre-loudness war dynamics may be reached in about ten years. As an exception, macrodynamics, which have not been significantly influenced by the loudness war, appear to increase since the loudness war’s peak, and are currently reaching very high values."

The article includes plots showing the evolution of RMS power, EBU3341 integrated loudness, crest factor, PRRC, HLSD and EBU3342 Loudness Range over the years. It's great to see such a thorough analysis on the topic.

Dynamics and Low-Frequency Ratio in Popular Music Recordings since 1965

by MICHAEL OEHLER, CHRISTOPH REUTER, AND ISABELLA CZEDIK-EYSENBERG
57th International AES Conference: The Future of Audio Entertainment Technology – Cinema, Television and the Internet (March 2015)

This study takes another look at the loudness and dynamic range trends over the last several decades, this time with a focus on the German music market:

The loudness, dynamic range and energy distribution in low-frequency bands of popular music are analyzed. One objective was to operationalize popular music and construct a robust, balanced sample that covers a specific but relevant music market regarding annual revenues. The sample consists of the “German Top 40” year-end charts from 1965 to 2013. Furthermore, different methods of measurement, such as LKFS or dBFS RMS, are used and compared. It could be shown that there was a significant increase of loudness, a decrease of the dynamic range and an increasing importance of the low-frequency bands over time. While our results correspond to most previous research, there is a major difference regarding the recent data. It is frequently mentioned in studies that the process of decreasing dynamic range peaked in 2004, and after that the opposite trend occurred, namely, an increase in dynamic range. In the German music market, however, this seems to be true only for the time span from 2004 to 2010. From 2011 to 2013 a significant decrease of the dynamic range and an increase in loudness were found.

 http://www.aes.org/e-lib/browse.cfm?elib=17612&rndx=928073

Another interesting article from Alex Wilson and Bruno Fazenda -

"Characterisation of Distortion Profiles in Relation to Audio Quality" (Proc. of the 17th Int. Conference on Digital Audio Effects (DAFx-14), Erlangen, Germany, September 1-5, 2014, http://www.dafx14.fau.de/papers/dafx14_alex_wilson_categorisation_of_distort.pdf ):

"Since digital audio is encoded as discrete samples of the audio waveform, much can be said about a recording by the statistical properties of these samples. In this paper, a dataset of CD audio

samples is analysed; the probability mass function of each audio clip informs a feature set which describes attributes of the musical recording related to loudness, dynamics and distortion. This

allows musical recordings to be classified according to their “distortion character”, a concept which describes the nature of amplitude distortion in mastered audio. A subjective test was designed

in which such recordings were rated according to the perception of their audio quality. It is shown that participants can discern between three different distortion characters... This expands upon previous work showing links between the effects of dynamic range compression and audio quality in musical recordings, by highlighting perceptual differences."

Is Pop Music Evolving or Is It Just Getting Louder?

http://blogs.scientificamerican.com/observations/2012/07/26/is-pop-music-evolving-or-is-it-just-getting-louder/

Vickers's Law: There are infinitely more ways to make sounds sound worse than there are to make them sound better.

(This assumes that we define "better" as being more similar (e.g., in a least squares sense) to some desired (clean) sound.)

A new DAFX article of interest: Alex Wilson and Bruno Fazenda, "Perception & Evaluation of Audio Quality in Music Production", http://dafx13.nuim.ie/papers/04.dafx2013_submission_47.pdf . From the abstract:

A dataset of audio clips was prepared and audio quality assessed by subjective testing.... A new objective metric is proposed, describing the Gaussian nature of a signal’s amplitude distribution. Correlations between objective measurements of the music signals and the subjective perception of their quality were found. Existing metrics were adjusted to match quality perception. A number of timbral, spatial, rhythmic and amplitude measures, in addition to predictions of emotional response, were found to be related to the perception of quality. The emotional features were found to have most importance, indicating a connection between quality and a unified set of subjective and objective parameters.

I just noticed an article, "'Dynamic Range' & The Loudness War" by Emmanuel Deruty, in the Sept. 2011 SOS, http://www.soundonsound.com/sos/sep11/articles/loudness.htm .

This article is very interesting - not sure what to make of it. It claims to prove that music is not getting less dynamic.

My AES paper on the topic, http://www.sfxmachine.com/docs/loudnesswar/ , found a noticeable decrease of "dynamic range" from 1985 to 2010 (from almost 13 dB to less than 8 dB), but this used the "TT Dynamic Range Meter", which actually measures something more like crest factor than dynamic range.

I agree that the term "Dynamic Range" is ill-defined and maybe not relevant here - a statistical measure would be more appropriate. It would be surprising to me if the "Loudness Range" (http://www.aes.org/e-lib/browse.cfm?elib=16254) has not decreased - I'd be curious to hear what the original creators of the Loudness Range measure would say about this.

Clearly more work is needed to figure out how musical dynamics have changed and which measures are most relevant.