Loudness war
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The loudness war (or loudness race) refers to the trend of increasing audio levels in recorded music which many critics believe reduces sound quality and listener enjoyment. Increasing loudness was first reported as early as the 1940s, with respect to mastering practices for 7" singles.[1] The maximum peak level of analog recordings such as these is limited by varying specifications of electronic equipment along the chain from source to listener, including vinyl and Compact Cassette players. The issue garnered renewed attention starting in the 1990s with the introduction of digital signal processing capable of producing further loudness increases.
With the advent of the Compact Disc (CD), music is encoded to a digital format with a clearly defined maximum peak amplitude. Once the maximum amplitude of a CD is reached, loudness can be increased still further through signal processing techniques such as dynamic range compression and equalization. Engineers can apply an increasingly high ratio of compression to a recording until it more frequently peaks at the maximum amplitude. In extreme cases, efforts to increase loudness can result in clipping and other audible distortion. Modern recordings that use extreme dynamic range compression and other measures to increase loudness therefore can sacrifice sound quality to loudness. The competitive escalation of loudness has led music fans and members of the musical press to refer to the affected albums as "victims of the loudness war."
History
The practice of focusing on loudness in audio mastering can be traced back to the introduction of the compact disc, but also existed to some extent when the vinyl phonograph record was the primary released recording medium and when 7-inch singles were played on jukebox machines in clubs and bars.
Jukeboxes became popular in the 1940s and were often set to a predetermined level by the owner, so any record that was mastered louder than the others would stand out.
Similarly, starting in the 1950s, producers would request louder 7-inch singles so that songs would stand out when auditioned by program directors for radio stations.[1] In particular, many Motown records pushed the limits of how loud records could be made; according to one of their engineers, they were "notorious for cutting some of the hottest 45s in the industry."[2]
In the 1960s and 1970s, compilation albums of hits by multiple different artists became popular, and if artists and producers found their song was quieter than others on the compilation, they would insist that their song be remastered to be competitive.
Because of the limitations of the vinyl format, the ability to manipulate loudness was also limited. Attempts to achieve extreme loudness could render the medium unplayable. Digital media such as CDs remove these restrictions and as a result, increasing loudness levels have been a more severe issue in the CD era.[3] Modern computer-based digital audio effects processing allows mastering engineers to have greater direct control over the loudness of a song: for example, a "brick wall" limiter can look ahead at an upcoming signal to limit its level.[4]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Masvis-zz_top-sharp_dressed_man.gif/220px-Masvis-zz_top-sharp_dressed_man.gif)
The stages of CD loudness increase are often split over the decades of the medium's existence.
1980s
Since CDs were not the primary medium for popular music until the late 1980s, there was little motivation for competitive loudness practices then. The common practice of mastering music for CD involved matching the highest peak of a recording at, or close to, digital full scale, and referring to digital levels along the lines of more familiar analog VU meters. When using VU meters, a certain point (usually −14 dB below the disc's maximum amplitude) was used in the same way as the saturation point (signified as 0 dB) of analog recording, with several dB of the CD's recording level reserved for amplitude exceeding the saturation point (often referred to as the "red zone", signified by a red bar in the meter display), because digital media cannot exceed 0 decibels relative to full scale (dBFS).[citation needed] The average level of the average rock song during most of the decade was around −16.8 dBFS.[6]: 246
1990s
By the early 1990s, mastering engineers had learned how to optimize for the CD medium and the loudness war had not yet begun in earnest.[7] However, in the early 1990s, CDs with louder music levels began to surface, and CD levels became more and more likely to bump up to the digital limit,[note 1] resulting in recordings where the peaks on an average rock or beat-heavy pop CD hovered near 0 dB,[note 2] but only occasionally reached it.[citation needed]
The concept of making music releases "hotter" began to appeal to people within the industry, in part because of how noticeably louder some releases had become and also in part because the industry believed that customers preferred louder-sounding CDs, even though that may not have been true.[8] Engineers, musicians, and labels each developed their own ideas of how CDs could be made louder.[9] In 1994, the digital brickwall limiter with look-ahead (to pull down peak levels before they happened) was first mass-produced. While the increase in CD loudness was gradual throughout the 1990s, some opted to push the format to the limit, such as on Oasis's widely popular album (What's the Story) Morning Glory?, which averaged −8 dBFS on many of its tracks—a rare occurrence, especially in the year it was released (1995).[7]
2000s
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b0/Metallica_My_Apocalypse_waveform.png/220px-Metallica_My_Apocalypse_waveform.png)
In 2008, loud mastering practices received mainstream media attention with the release of Metallica's Death Magnetic album. The CD version of the album has a high average loudness that pushes peaks beyond the point of digital clipping, causing distortion. This was reported by customers and music industry professionals, and covered in multiple international publications, including Rolling Stone,[10] The Wall Street Journal,[11] BBC Radio,[12] Wired,[13] and The Guardian.[14] Ted Jensen, a mastering engineer involved in the Death Magnetic recordings, criticized the approach employed during the production process.[15] A version of the album without dynamic range compression was included in the downloadable content for the video game Guitar Hero III.[16]
In late 2008, mastering engineer Bob Ludwig offered three versions of the Guns N' Roses album Chinese Democracy for approval to co-producers Axl Rose and Caram Costanzo. They selected the one with the least compression. Ludwig wrote, "I was floored when I heard they decided to go with my full dynamics version and the loudness-for-loudness-sake versions be damned." Ludwig said the "fan and press backlash against the recent heavily compressed recordings finally set the context for someone to take a stand and return to putting music and dynamics above sheer level."[17]
2010s
In March 2010, mastering engineer Ian Shepherd organised the first Dynamic Range Day,[18] a day of online activity intended to raise awareness of the issue and promote the idea that "Dynamic music sounds better". The day was a success and its follow-ups in the following years have built on this, gaining industry support from companies like SSL, Bowers & Wilkins, TC Electronic and Shure[19] as well as engineers like Bob Ludwig, Guy Massey and Steve Lillywhite.[20] Shepherd cites research showing there is no connection between sales and loudness, and that people prefer more dynamic music.[21][22] He also argues that file-based loudness normalization will eventually render the war irrelevant.[23]
One of the biggest albums of 2013 was Daft Punk's Random Access Memories, with many reviews commenting on the album's great sound.[24][25] Mixing engineer Mick Guzauski deliberately chose to use less compression on the project, commenting "We never tried to make it loud and I think it sounds better for it."[26] In January 2014 the album won five Grammy Awards, including Best Engineered Album (Non-Classical).[27]
In October 2013, Bob Katz announced on his website that "The last battle of the loudness war has been won", claiming that Apple's mandatory use of Sound Check for iTunes Radio meant that "The way to turn the loudness race around right now, is for every producer and mastering engineer to ask their clients if they have heard iTunes Radio. When they respond in the affirmative, the engineer/producer tells them they need to turn down the level of their song(s) to the standard level or iTunes Radio will do it for them. He or she should also explain that overcompressed material sounds 'wimpy' and 'small' in comparison to more open material on iTunes Radio." He believes this will eventually result in producers and engineers making more dynamic masters to take account of this factor.[28] His point of view has been widely reported and discussed.[29][30]
Analysis suggests that the loudness trend may have peaked around 2005 and subsequently reduced, with a pronounced increase in overall and minimum album DR (crest factor) for albums since 2005.[31][32]
Replay volume normalization
With music sales moving towards file-based playback and streaming and away from CDs, there is a possibility that the loudness war will be blunted by normalization technology such as ReplayGain and Apple's Sound Check.[33] Most cloud-based music services perform loudness normalization by default and may reduce the market pressure to overcompress material.[34]
Replay volume normalization also helps when listening to playlists or shuffle play where otherwise variations in perceived loudness of recordings results in uncomfortable loudness shifts.[35]
Broadcasting
Broadcasting is also a participant in the loudness war. Competition for listeners between radio stations has contributed to a loudness "arms race".[36] Loudness jumps between broadcast channels and between programmes within the same channel, and between programs and intervening adverts are a frequent source of audience complaints.[37] The European Broadcasting Union is addressing this issue in the EBU PLOUD Group, which includes over 230 audio professionals, many from broadcasters and equipment manufacturers.
Criticism
This practice (excessive compression, dynamic range reduction, loudness level enhancement, etc.) has been condemned by several recording industry professionals including Alan Parsons, Geoff Emerick[38] (noted for his work with the Beatles from Revolver to Abbey Road), and mastering engineers Doug Sax,[2] Steve Hoffman, and many others, including music audiophiles, hi-fi enthusiasts, and fans. Musician Bob Dylan has also condemned the practice, saying: "You listen to these modern records, they're atrocious, they have sound all over them. There's no definition of nothing, no vocal, no nothing, just like—static." The compact disc editions of Dylan's more recent albums Modern Times and Together Through Life are examples of heavy dynamic range compression, although Dylan himself might not have been responsible for it.[39]
When music is broadcast over radio, the station applies its own signal processing, further reducing the dynamic range of the material to closely match levels of absolute amplitude, regardless of the original recording's loudness.[40] This technique is also used as a security feature to prevent quiet passages or fade-outs from becoming dead air.
Opponents have called for immediate changes in the music industry regarding the level of loudness. In August 2006, the vice-president of A&R for One Haven Music, a Sony Music company, in an open letter decrying the loudness war, claimed that mastering engineers are being forced against their will or are preemptively making releases louder to get the attention of industry heads.[3] Some bands are being petitioned by the public to re-release their music with less distortion.[38]
The nonprofit organization Turn Me Up![41] was created by Charles Dye, John Ralston, and Allen Wagner to certify albums that contain a suitable level of dynamic range[42] and encourage the sale of quieter records by placing a "Turn Me Up!" sticker on albums that have a larger dynamic range.[43] The group has not yet arrived at an objective method for determining what will be certified.[44]
A hearing researcher at House Ear Institute in Los Angeles is concerned that the loudness of new albums could possibly harm listeners' hearing, particularly that of children.[43]
A 2-minute YouTube video addressing this issue by audio engineer Matt Mayfield[45] has been referenced by The Wall Street Journal[46] and the Chicago Tribune.[47] Pro Sound Web quoted Mayfield: "When there is no quiet, there can be no loud."[48]
The book Perfecting Sound Forever: An Aural History of Recorded Music, by Greg Milner presents the loudness war in radio and music production as a central theme.[9] The book Mastering Audio: The Art and the Science, by Bob Katz, includes chapters about the origins of the loudness war and another suggesting methods of combating the war,[6]: 241 based on Katz's presentation at the 107th Audio Engineering Society Convention (1999) and his Audio Engineering Society Journal publication (2000).[49]
Debate
In 2007, Suhas Sreedhar published an article about the loudness war in the engineering magazine IEEE Spectrum.[35] Sreedhar said that the greater possible dynamic range of CDs was being set aside in favor of maximizing loudness using digital technology. Sreedhar said that the overcompressed modern music was fatiguing, that it did not allow the music to "breathe".[35]
In September 2011, Emmanuel Deruty wrote in Sound on Sound, a recording industry magazine, that the loudness war has not led to a decrease in dynamic variability in modern music, possibly because the original digitally-recorded source material of modern recordings is more dynamic than analogue material.[32] Deruty and Damien Tardieu criticized Sreedhar's methods in an AES paper, saying that Sreedhar had confused crest factor (peak minus RMS) with dynamics in the musical sense (pianissimo to fortissimo).[50] Deruty and Tardieu analyzed the "loudness range" (LRA) over a 45-year span of recordings, and observed that the crest factor of recorded music diminished significantly between 1985 and 2010, but the LRA remained relatively constant.[32]
This analysis has been challenged on the basis that the LRA was designed for assessing loudness variation within a track while the EBU R128 Peak to Loudness Ratio (PLR) is a measure of the peak level of a track relative to a reference loudness level. Ian Shepherd and Bob Katz wrote that PLR is a more helpful metric in assessing overall perceived dynamic range which shows a trend toward reduced dynamic range throughout the 1990s.[51][52]
Debate continues regarding which measurement methods are most appropriate to evaluating the loudness war.[53][54][55]
Examples of "loud" albums
Some of the albums that have been criticized for their sound quality include the following:
See also
- Alignment level
- Audio noise measurement
- Audio quality measurement
- Fader creep
- Headroom
- Loudness monitoring
- Needle drop
- Overproduction
- Pitch inflation
- Programme level
- Remaster
- Up to eleven
Notes
- ^ Up to 2 or 4 consecutive full-scale samples was considered acceptable.
- ^ Usually in the range of −3 dB.
- ^ Won Grammy Award in 2007 for Best Engineered Album, Non-Classical
- ^ The Guitar Hero version of this album does not have the same quality issues.
References
- ^ a b "The Loudness Wars: Why Music Sounds Worse". NPR. 31 December 2009. Retrieved 2010-09-02.
- ^ a b The Big Squeeze: Mastering engineers debate music's loudness wars, Mix Magazine, 1 December 2005, archived from the original on 25 August 2010, retrieved 2010-09-02
{{citation}}
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ignored (|url-status=
suggested) (help) - ^ a b c d e Joe Gross (2006-10-02), Everything Louder Than Everything Else, Austin 360, archived from the original on October 19, 2006, retrieved 2010-11-24
- ^ Mark Donahue, The Loudness War, Performer, retrieved 2010-11-24
- ^ "Sharp Dressed Man" plotted using MasVis, a freeware mastering analysis program.
- ^ a b Katz, Bob (2013). Mastering Audio: The Art and the Science (3rd ed.). Focal Press. ISBN 978-0-240-81896-2.
- ^ a b c d e f g Southall, Nick (2006-05-01). "Imperfect Sound Forever". Stylus Magazine. Archived from the original on 2006-06-12.
{{cite magazine}}
: Cite magazine requires|magazine=
(help) - ^ Viney, Dave (December 2008). "The Obsession With Compression" (PDF): 54. Retrieved 24 July 2011.
there is no evidence of any significant correlation between loudness (& implied compression) and commercial success
{{cite journal}}
: Cite journal requires|journal=
(help) - ^ a b Milner, Greg (2012). Perfecting Sound Forever: An Aural History of Recorded Music. Granta Publications. ISBN 9781847086051.
- ^ Kreps, Daniel (2008-09-18). "Fans Complain After "Death Magnetic" Sounds Better on "Guitar Hero" Than CD". Rolling Stone. Retrieved 2011-03-15.
- ^ Smith, Ethan (2008-09-25). "Even Heavy-Metal Fans Complain That Today's Music Is Too Loud!!!". Wall Street Journal. Retrieved 2008-10-17.
- ^
"'Death Magnetic' Sound Quality Controversy Focus Of BBC RADIO 4 Report". BlabberMouth.net. 2008-10-10. Archived from the original on 2008-10-13. Retrieved 2008-10-17.
{{cite web}}
: Unknown parameter|deadurl=
ignored (|url-status=
suggested) (help) - ^ Van Buskirk, Eliot (2008-09-16). "Analysis: Metallica's Death Magnetic Sounds Better in Guitar Hero". Wired. Retrieved 2008-09-17.
- ^ Michaels, Sean (2008-10-01). "Death Magnetic 'loudness war' rages on". London: The Guardian. Retrieved 2008-10-17.
- ^ Michaels, Sean (2008-09-17). "Metallica album latest victim in 'loudness war'?". London: The Guardian. Retrieved 2008-09-17.
- ^ Vinnicombe, Chris (2008-09-16). "Death Magnetic Sounds Better in Guitar Hero". MusicRadar. Retrieved 2008-09-18.
- ^
Ludwig, Bob (November 25, 2008). "Guns 'N Roses: Dynamics and quality win the Loudness Wars". Loudness Wars. Gateway Mastering. Archived from the original on January 31, 2009. Retrieved March 29, 2010.
{{cite web}}
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ignored (|url-status=
suggested) (help) - ^ "Dynamic Range Day". Dynamic Range Day.
- ^ Dynamic Range Day heralds new movement against loudness, Pro Sound News, February 22, 2011
- ^ Ian Shepherd. "What do Steve Lillywhite, Guy Massey and Bob Ludwig think of Dynamic Range Day ?". DynamicRangeDay.com. Retrieved September 17, 2014.
- ^ Earl Vickers (November 4, 2010). "The Loudness War: Background, Speculation and Recommendations" (PDF). AES 2010: Paper Sessions: Loudness and Dynamics. San Francisco: Audio Engineering Society. Retrieved July 14, 2011.
- ^ Earl Vickers. "The Loudness War: Background, Speculation and Recommendations – Additional material". Retrieved 2012-02-08.
- ^ Ian Shepherd. "Lust for Level - Audio perception and the battle for great sound". Retrieved 2012-02-08.
- ^ Mark Richardson. "Random Access Memories - Pitchfork Review". Retrieved 2014-02-06.
- ^ Melissa Maerz. "Random Access Memories - Music Review". Entertainment Weekly. Retrieved 2014-02-06.
- ^ Michael Gallant. "Mick Guzauski on Mixing Daft Punk". Retrieved 2014-02-06.
- ^ "Daft Punk get lucky at Grammy Awards". BBC News. Retrieved 2014-02-06.
- ^ Bob Katz. "The Loudness War Has Been Won: Press Release". Retrieved 2014-02-06.
- ^ Hugh Robjohns. "The End Of The Loudness War?". Sound On Sound. Retrieved 2014-02-06.
- ^ Ian Shepherd. "Has The Loudness War Been Won?". Retrieved 2014-02-06.
- ^ Tristan Collins. "Dynamic Range Analysis 1970-Present". Retrieved 2014-02-06.
- ^ a b c Deruty, Emmanuel (September 2011). "'Dynamic Range' & The Loudness War". Sound on Sound. Retrieved 2013-10-24.
- ^ Greg Reierson (2011-02-08), The Loudness War is Over, Mix
- ^ Ian Shepherd (2009-10-23). "How Spotify will end the Loudness Wars". productionadvice.co.uk.
- ^ a b c "The Future of Music". ieee.org. Archived from the original on 2007-10-14.
{{cite web}}
: Unknown parameter|deadurl=
ignored (|url-status=
suggested) (help) - ^ "Interview with Inovonics CEO Jim Wood at Radioworld". Archived from the original on November 4, 2004.
- ^ Moerman, Jean Paul (May 1, 2004), Loudness in TV Sound, Audio Engineering Society,
We started this paper with viewer complaints. At Belgian National Broadcasters VRT, located in Brussels, about 140 complaints per year were about sound. Since the implementation of the master plan there was a spectacular downfall to 3 complaints in 2003. This demonstrates again the efficiency of the master plan.
- ^ a b Adam, Sherwin (2007-06-07), Why music really is getting louder, The Times, retrieved 2007-06-12
- ^ a b c Curnyn, Sean (September 3, 2009). "Tears of Rage: The Great Bob Dylan Audio Scandal." Retrieved on March 2, 2010.
- ^ What Happens To My Recording When It's Played On The Radio? also available from the AES library
- ^ Turn Me Up! website
- ^ Will the loudness wars result in quieter CDs?, The Guardian, January 10, 2008
- ^ a b Emery, Chris (November 25, 2007). "Audio gain in volume signals loss for listeners". The Baltimore Sun. Retrieved September 2, 2010.
- ^ Turn Me Up! About Us. Retrieved on August 13, 2009.
- ^ The Loudness War on YouTube
- ^ Even Heavy-Metal Fans Complain That Today's Music Is Too Loud!!!, The Wall St. Journal, September 25, 2008
- ^ Loudness war stirs quiet revolution by audio engineers, Chicago Tribune, January 4, 2008
- ^ "Video: The Loudness Wars Exposed: "When there is no quiet, there can be no loud."". Study Hall. Pro Sound Web. March 30, 2011. Retrieved April 4, 2011.
- ^ Integrated Approach to Metering, Monitoring and Leveling Practices (article text)
- ^ Emmanuel Deruty, Damien Tardieu (January 2014). "About Dynamic Processing in Mainstream Music". Journal of the Audio Engineering Society. Retrieved 2014-06-06.
- ^ Ian Shepherd. "Why the Loudness War hasn't reduced 'Loudness Range'". Retrieved 2014-02-06.
- ^ Jason Victor Serinus. "Winning the Loudness Wars". Stereophile. Retrieved 2014-02-06.
- ^ Esben Skovenborg (April 2012). "Loudness Range (LRA) – Design and Evaluation". AES 132nd Convention. Retrieved 2014-10-25.
{{cite web}}
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suggested) (help) - ^ Jon Boley, Michael Lester and Christopher Danner (November 2010). "Measuring Dynamics: Comparing and Contrasting Algorithms for the Computation of Dynamic Range". AES 129th Convention. Retrieved 2014-10-25.
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ignored (|url-access=
suggested) (help) - ^ Jens Hjortkjær, Mads Walther-Hansen (January 2014). "Perceptual Effects of Dynamic Range Compression in Popular Music Recordings". Journal of the Audio Engineering Society. Retrieved 2014-06-06.
{{cite web}}
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ignored (|url-access=
suggested) (help) - ^ "CD Review: Alice in Chains, "Black Gives Way to Blue"". Popdose. Retrieved 2016-03-15.
- ^ "Black Sabbath's New Album, '13'". The New York Times.
- ^ Doran, John (2008-09-27). "Review The Cure 4:13 Dream". The Quietus.
- ^ Stagg, Brian (2005-10-20). "Depeche Mode - Playing The Angel - Another victim of the loudness race".
- ^ Roos, Dave. "Complaints with Remastering CDs". HowStuffWorks. Retrieved April 8, 2015.
- ^ Levine, Robert. "The Death of High Fidelity: In the age of MP3s, sound quality is worse than ever". Rolling Stone. Archived from the original on July 1, 2008. Retrieved December 1, 2010.
- ^ "Metallica Face Criticism Over Sound Quality of "Death Magnetic"". Rolling Stone.
- ^ Country WeeklyMagazine review from October 19, 2009
- ^ "Halo Profile 02R: Pretty Hate Machine 2010". TheNINHotline.
- ^ "The Bicycle Music Company - Pretty Hate Machine Press Release" (PDF). October 26, 2010. Archived from the original (PDF) on July 7, 2011. Retrieved 2017-02-02.
{{cite web}}
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ignored (|url-status=
suggested) (help) - ^ "The Nevermind 20th Anniversary Release: Anatomy of a Disaster". Lost Turntable. Retrieved 2016-03-20.
- ^ "Nevermind [20th Anniversary Deluxe Edition]". AllMusic. Retrieved 2017-02-02.
- ^ Anderson, Tim (2008-01-10). "Will the loudness wars result in quieter CDs?". The Guardian.
- ^ a b Anderson, Tim (January 18, 2007). "How CDs are remastering the art of noise." Retrieved on March 12, 2012.
- ^ "Laid Off Loser Album of the Day: "Ten Deluxe Edition"". Laid Off Loser Blog.
- ^ "Thoughts on Pearl Jam's Ten (Remastered)". Overclock.net Forum.
- ^ "Pearl Jam reissues album "Ten"". Whirlpool.net Forum.
- ^ Rowan, Rip (August 31, 2002). "Over The Limit". ProRec.com. Archived from the original on June 10, 2008. Retrieved May 21, 2010.
- ^ Matt Medved. "Taylor Swift's '1989' Is Louder Than AC/DC's 'Back in Black' -- Here's Why". Retrieved 2018-03-29.
Further reading
- Level and distortion in digital broadcasting
- On the way to Loudness Nirvana – Audio levelling with EBU R 128
- Wickham, Chris (26 July 2012). "Pop music too loud and all sounds the same: official". Reuters.
- Serrà, J; Corral, A; Boguñá, M; Haro, M; Arcos, JL (26 July 2012). "Measuring the Evolution of Contemporary Western Popular Music". Scientific Reports. 2: 521. arXiv:1205.5651. Bibcode:2012NatSR...2E.521S. doi:10.1038/srep00521. PMC 3405292. PMID 22837813. Retrieved 26 July 2012.
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(help) - Llewellyn Hinkes-Jones (2013-11-25). "The Real Reason Music's Gotten So Loud". The Atlantic. Retrieved 2013-11-25.
{{cite journal}}
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(help) - Devine, K. (2013). "Imperfect sound forever: Loudness wars, listening formations and the history of sound reproduction". Popular Music. 32 (2): 159. doi:10.1017/S0261143013000032.
- Stuart Dredge (2013-11-25). "Pop music is louder, less acoustic and more energetic than in the 1950s". The Guardian. Retrieved 2013-11-25.