The Musical Diversity of Pop Songs
Are Pop Lyrics Getting More Repetitive
Vickers, E., (2010)
The Loudness War: Background, Speculation and Recommendations
AES 129th Convention, San Francisco, CA, USA 2010 Nov 4-7 (Conference Proceedings - non periodical)
Serrà, J., Corral, Á., Boguñá, M., Haro, M., & Arcos, J.L. (2012).
Measuring the Evolution of Contemporary Western Popular Music.
Scientfic Reports, 2, Article 521.
https://www.nature.com/articles/srep00521
Percino, G., Klimek, P., Thurner, S., (2014)
Instrumental Complexity of Music Genres and Why Simplicity Sells
PLoS ONE 9(12): e115255
Mauch, M., MacCallum R.M., Levy, M., Leroi, A.M. (2015).
The evolution of popular music: USA 1960-2010
Royal Society Open Science, DOI: 10.1098/rsos.150081.
http://rsos.royalsocietypublishing.org/content/2/5/150081
Askin, N., Mauskapf, M. (2017)
What Makes Popular Culture Popular? Product Features and Optimal Differentiation in Music.
American Sociological Review, Vol: 82 issue: 5, page(s): 910-944.
http://journals.sagepub.com/doi/abs/10.1177/0003122417728662
I think the important thing is to remember these studies focus on ‘popular’ music ie what is marketable to the lowest common denominator in order to maximize sales.
I would always squeal with glee whenever another engineer would demolish the cherished subjective world view of the audiophile cognoscenti. Bob Carver remains a hero of mine.