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Further, current compression equipment allows engineers to create a recording that has a nearly uniform dynamic range. [http://www.cdmasteringservices.com/dynamicrange.htm] When that level is set very close to the maximum allowed by the CD format, this creates near-continuous distortion throughout the disc. [http://www.cdfreaks.com/news/10109] |
Further, current compression equipment allows engineers to create a recording that has a nearly uniform dynamic range. [http://www.cdmasteringservices.com/dynamicrange.htm] When that level is set very close to the maximum allowed by the CD format, this creates near-continuous distortion throughout the disc. [http://www.cdfreaks.com/news/10109] |
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This situation has been widely condemned.[http://www.barrydiamentaudio.com/loudness.htm] [http://www.prorec.com/prorec/articles.nsf/articles/8A133F52D0FD71AB86256C2E005DAF1C] Some have petitioned their favorite groups to rerelease some CDs with less distortion. |
This situation has been widely condemned.<ref>[http://www.barrydiamentaudio.com/loudness.htm "Declaring an end to the loudness wars"] at Barry Diament Audio</ref><ref>[http://www.prorec.com/prorec/articles.nsf/articles/8A133F52D0FD71AB86256C2E005DAF1C]</ref> Some have petitioned their favorite groups to rerelease some CDs with less distortion.<ref>[http://forum.doom9.org/showthread.php?t=103702 "Petition: Red Hot Chili Peppers CD Re-Mastering (Fix Clipping & Compression)"] at Doom9 forum</ref> Others have even said that recording engineers who knowingly push their recording equipment past clipping should be blacklisted and not allowed to "victimize artists or music lovers."<ref>[http://www.drewdaniels.com/phil.htm The Essentials of Fine Audio Recording] at DrewDaneils.com</ref> Many have suggested boycotting such recordings. |
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It should be made clear that this distortion is different from other kinds of distortion such as overdrive or feedback (see [[Overdrive (music)]]), which is created by electronic musical instruments, not by the recording process, and which can be an intentional and integral part of the performance. Digital clipping is created through the recording process, not by instruments creating sound naturally, though musicians have been accused of requesting the sorts of loudness that encourages this phenomenon. However, sometimes [[analog signal|analog]]-style distortion is used in the mastering process to achieve similar results, either through analog tape saturation and valve distortion prior to digital transfer or computer software used to emulate these processes. |
It should be made clear that this distortion is different from other kinds of distortion such as overdrive or feedback (see [[Overdrive (music)]]), which is created by electronic musical instruments, not by the recording process, and which can be an intentional and integral part of the performance. Digital clipping is created through the recording process, not by instruments creating sound naturally, though musicians have been accused of requesting the sorts of loudness that encourages this phenomenon. However, sometimes [[analog signal|analog]]-style distortion is used in the mastering process to achieve similar results, either through analog tape saturation and valve distortion prior to digital transfer or computer software used to emulate these processes. |
Revision as of 20:16, 10 October 2006
The phrase loudness war (or loudness race) refers to the practice of recording music at progressively higher and higher levels, to create CDs that sound perceptibly as loud as possible or "louder" than CDs from competing artists or recording labels. While the overall maximum amplitude of a CD cannot be increased, reducing the dynamic range of the signal using audio compression will cause the human ear-brain mechanism to perceive the overall signal as being louder, when in fact merely the difference between loud and quiet portions of audio has been reduced.
Introduction
![](https://upload.wikimedia.org/wikipedia/commons/thumb/4/49/Lindos4.svg/300px-Lindos4.svg.png)
One reason for this practice is that when comparing two CDs of differing levels, it is likely that the louder one will be regarded as sounding better on first impression. This can partly be attributed to the way in which the human ear responds to sound pressure at different levels, as its frequency response will change according to differences in sound pressure level (SPL), with the listener perceiving a greater amount of low and high frequency content as SPL increases.[1][2] Higher levels can also result in subjectively better sounding recordings on low quality reproduction systems, such as web audio formats, AM radio, mono television and telephones, but since most of the material affected is delivered via CD audio, and it has enhanced dynamic range, it is often detrimental to overall quality.
To educated ears this practice is unnecessary, since if listeners want to listen to loud music, they can simply turn up the volume on their playback equipment. If a CD is broadcast by a radio station, the station will have its own equipment that reduces the dynamic range of material it broadcasts to far more closely matching levels of absolute amplitude, regardless of the original recording's loudness.[3][4]
This practice often results in a form of distortion known as clipping.[5] The loudness wars have reached a point at which most pop CDs, and many classical and jazz CDs, have large amounts of digital clipping, making them harsh and fatiguing to listen to, especially, ironically, on high quality equipment.[2] On the CDs where clipping does not occur—or does not occur as frequently as would when simple digital amplification is involved—a process known as limiting is used. While the resulting distortion is lessened from the final product this way, it unfortunately has the side effect of significantly reducing transient response, most often heard as lessened drum impact and, when taken to severe levels, can reduce the natural dynamic ranges of other instruments within the recording and, depending on the opinion of the listener, reduce sonic clarity. Both methods can be relatively transparent in moderate cases; however with the levels that are commonly demanded as of now this is seldom a possibility.
Further, current compression equipment allows engineers to create a recording that has a nearly uniform dynamic range. [3] When that level is set very close to the maximum allowed by the CD format, this creates near-continuous distortion throughout the disc. [4]
This situation has been widely condemned.[6][7] Some have petitioned their favorite groups to rerelease some CDs with less distortion.[8] Others have even said that recording engineers who knowingly push their recording equipment past clipping should be blacklisted and not allowed to "victimize artists or music lovers."[9] Many have suggested boycotting such recordings.
It should be made clear that this distortion is different from other kinds of distortion such as overdrive or feedback (see Overdrive (music)), which is created by electronic musical instruments, not by the recording process, and which can be an intentional and integral part of the performance. Digital clipping is created through the recording process, not by instruments creating sound naturally, though musicians have been accused of requesting the sorts of loudness that encourages this phenomenon. However, sometimes analog-style distortion is used in the mastering process to achieve similar results, either through analog tape saturation and valve distortion prior to digital transfer or computer software used to emulate these processes.
Another consequence of the loudness war is that even if there is no distortion, the sound of the CD utilizing the upper amplitude ranges will have a narrow dynamic range, with less rise, fall or sense of dynamic shaping. The music has been "squashed", so to speak. Pop music in general has not been interested in the expressive possibilities of crescendos, diminuendos, sudden loudness or quietness, or any of the other dynamic devices available to musicians, but the loudness war has eliminated even the possibility of dynamic expressiveness in recorded pop music. That said, lack of a wide dynamic range is not necessarily the result of attempting loudness, as loudness-based compressors (such as limiters) are designed to be as transparent of the original signal as possible, which means that macrodynamics (the difference in volume between sections of a song) are relatively unaffected by such processes. Often slow-acting, broadcast-style compression will be applied to the music to make the differences in volume between song sections more uniform for background listening or noisy environments (such as in the car), while multi-band compression is commonly used to make a mix more uniform and easier to balance, more compatible with low-end equipment and/or to achieve a certain "sound" or artistic effect.
History
(Note: Some of these examples are explained using RMS (Root Mean Square) power values. In reference to CD audio, these values are based on the calculation of the average of CD audio sample values with digital full scale used as a reference. It is a common way to determine the absolute loudness of a recording, though discrepancies in musical arrangements can cause inconsistencies in regards to aforementioned value versus perceived loudness.)
Due to the subjective nature of hearing, distinguishable stages of the loudness war and its impact will vary quite a bit chronologically depending on whom you inquire. The practice of focusing on loudness in mastering can not only be traced back to the introduction of the compact disc itself, but has also been said to exist when vinyl was the primary released recording medium. However, because of the limitations of the vinyl format, loudness and compression on a released recording were restricted in order to make the physical medium playable—restrictions distant from the infinite possibilities of digital playback media such as CDs—and as a result never reached the significance that they have in the CD era. Extraordinarily hot recording levels like those showcased by Japanese noise artist Merzbow, which are significantly louder than even today's norm, would be impossible on vinyl.
The stages of CD loudness is often split over the three decades of the medium's existence. Since CDs were not the primary medium for popular music until the tail end of the 1980s, there was little motivation for competitive loudness practices then. That CD players were also very expensive and thus commonly exclusive to high-end systems that benefited less from advanced recording levels during this period is another major factor. (In addition, one should note that for a period of about four or five years, there was absolutely no way for a recording to be limited in the digital domain, signal processing in the digital domain for mastering engineers just did not exist.) As a result, the two common practices of mastering CDs involved either matching the highest peak of a recording at, or close to, digital full scale, or referencing digital levels along the lines of more familiar analog VU meters. For the VU meters a certain point (usually −6 dB, or 50% of the disc's amplitude on a linear scale) was used in the same way as the saturation point (signified as 0db) of analog recording, with several dB of the CDs 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), except that there would be no saturation of the peaks since the medium was digital. The RMS level of the average rock song during most of the decade was around −18 dB.
At the turn of the decade CDs louder than this level began to surface, and CD volumes became more and more likely to exceed the digital limit as long as such amplification would not involve clipping more than approximately 2-4 digital samples, resulting in recordings where the peaks on an average rock or beat-heavy pop CD hovered close (usually in the range of 3 dB) to full scale but only occasionally reached it. Guns N' Roses's 1987 album Appetite for Destruction is an early example of this, with RMS levels averaging −15 dB for all the tracks. In the early '90s, however, some mastering engineers decided to take this a step further, and treat the CDs levels exactly as they would the levels of an analog tape and equate digital full scale with the analog saturation point, with the recording just loud enough so that each (or almost every) beat would peak at or over full scale. Though there were some early cases (such as Metallica's self-titled Black Album in 1991), albums mastered in this fashion generally did not appear until 1992. Alice in Chains's Dirt, Rage Against the Machine's self-titled debut and Faith No More's Angel Dust are some examples from this year. This time period (1988-1992) was an extremely erratic time for CD mastering. The loudness of CDs varied massively depending on the philosophies of the engineer (and others involved in the mastering process) as CD mastering became more lenient. 1994 was arguably the year in which this style of "hot" mastering became commonplace, though exceptions, such as the album Superunknown by Soundgarden from the same year, still existed. The most common loudness for a rock CD in terms of RMS power was around −12 dB, though depending on how an album was mixed it could be higher or lower (as was the case with the Type O Negative album Bloody Kisses, a consistently-peaking melodic metal album released in 1993 averaging −14db, as well as the aforementioned 1991 Metallica release). Overall, most rock and pop CDs released in the '90s followed this method to a certain extent.
However, the concept of making CDs "hotter" began to enter the minds of people within the industry due to how noticeably louder CDs had become. Engineers, musicians and labels developed their own ideas of how much of the peaks could be compromised as some became fascinated with the concept of making a CD louder than another one. During the late '90s, the ethics of simply stopping at a general transparency point were steadily thrown out the window. Of course, while the process was for the most part gradual, some opted to push the format to the limit as soon as the means arose, such as Oasis, whose widely popular album (What's the Story) Morning Glory? hit a whopping −8 dB on many of its tracks, something almost completely unheard of, especially in the year it was released (1995), as well as Iggy Pop, who in 1997 assisted in the remix and remaster of the 1973 album Raw Power by his former band The Stooges, which to this day is arguably the loudest rock CD ever recorded, hitting a staggering −4 dB in places, and still barely touched by today's standards. Eventually, however, the standards of loudness would reach its limit in the '00s. And while some may debate the severity of the loudness war during its humble beginnings in the 1990s, there is little doubt in the minds of most audio enthusiasts that most rock and pop CDs released on large corporate labels (and not just RIAA-owned ones; independent metal label Century Media has been stated as being a major offender, for example) in the 21st century are simply unacceptable sound-wise; −10 dB has been the standard for the past several years, often pushed to −9 dB (and sometimes even a dB or two louder!). Exceptions to today's hot standards are practically non-existent now, and the chances of the situation reversing are very slim due to knowledge of the loudness war mostly being limited to audio enthusiasts and individuals within the audio field, demographics who make up a small portion of music buyers.
Interpretations
As stated before, views regarding the impact of the loudness war are heavily subjective. Many hold the opinion that only a handful of albums (such as the Red Hot Chili Peppers 1999 release Californication, a CD with such excessive amounts of high-frequency digital clipping that casual listeners as well as audio enthusiasts have made complaints) are examples worth considering, while other, more fanatical types believe any CD where digital full scale is frequently utilized (or when mastering processes are used solely to prevent such when attempting the same volume) should be considered unacceptable.[10][11] Some consider it a minor annoyance, others find themselves completely unable to listen to albums they feel are noticeable victims of loudness-based mastering.[12]
It can be said that the point where the loudness of a medium can become audibly intrusive is when the peaks of the pre-processed recording's waveform would exceed full scale when amplified to the desired level on numerous occasions; in rock music this means on each drum beat. The effects that this will have on the sound are widely variable and become exponentially more severe the more the sound is pushed over the digital limit, ranging from almost completely transparent to the trained ear to detrimentally fatiguing for nearly everyone. The "sweet spot" between transparent and unsatisfactory loudness-based mastering is oft identified at the level where the lowest-peaking snare drum (or in some cases the kick drum) transient during a charged rock beat just reaches the threshold where waveform alteration (either via clipping or processing) occurs; many mastering engineers use this as their "golden standard".
Although mastering engineers are the ones who create the hot CDs themselves, many of them proclaim their actions to be forced upon them, often blaming a variety of parties. The most commonly accused is the recording label, who are said to demand CDs of "competitive" playback levels and disallow the release of any disc that is not up to their commercially-oriented ideal of CD loudness, and who will simply hand the job over to another mastering engineer if the original one refuses to perform such a task, resulting in the defiant engineer being blacklisted by the label and deprived of their potential salary or even their career. Some accuse the artists and/or producers of being ignorant or apathetic of proper recording practices and requesting their CDs be made as loud as possible, while others blame mixing engineers with similar mindsets or lack of experience for compressing or distorting the mix prior to sending it off for mastering.
Remasters
![](https://upload.wikimedia.org/wikipedia/commons/thumb/2/22/Oneofus_1981.png/220px-Oneofus_1981.png)
![](https://upload.wikimedia.org/wikipedia/commons/thumb/4/4d/Oneofus_2005.png/220px-Oneofus_2005.png)
Recently many classic albums have been re-released in remastered form. In its most basic form, the current remastering practice is to boost the bass and treble frequencies (which does actually create a perceived improvement - see the Fletcher-Munson diagram above) and to boost the average level with the aid of compression.
The two screenshots here, of ABBA's One Of Us, demonstrate the effect.
The first image is taken from the original 1981 Polydor CD release, where there is no clipping or distortion, and plenty of headroom.
The second image is taken from the 2005 remaster (part of the Complete Studio Recordings box set). There is a heavy amount of compression, and all the dynamics and "snap" of the original track have been lost. As a result when this recording is played it becomes a "wall of sound".
While this effect is appropriate for some genres of music, it is clearly, as the original recording shows, not what was intended for this track.
The Popular Examples section contains several other remastered albums whose quality has, arguably, been degraded by the remastering process.
No winners in the loudness war
With the increasing rise in popularity of digital portable audio players such as the iPod, the practice of making releases ever hotter may become ineffective. The iTunes software has a feature called Sound Check, which calculates the perceived loudness of audio tracks as they are imported into the music library, and adjusts accordingly on playback. Windows Media Player has a similar feature (called simply Volume Leveling), and other formats such as FLAC calculate the perceived loudness as part of the encoding process, allowing the player to adjust the volume on a per-track basis.
The MP3 format now has this facility, using a free piece of software called mp3gain (as does the OGG format with vorbisgain). This software calculates the perceived loudness of an individual track, then adjusts the scale factor of each frame of the MP3 file to losslessly alter the playback level.
![](https://upload.wikimedia.org/wikipedia/commons/thumb/6/6b/Oneofus_2005_rg.png/220px-Oneofus_2005_rg.png)
When gain is adjusted like this, "hot" compressed tracks can often sound slightly quieter than older less compressed material. The most effective demonstration of this can be performed by comparing an original CD release to a remaster. Take the example above, "One Of Us" from ABBA's 1981 album "The Visitors". The screenshots here show the same two versions of "One Of Us" from the Remasters discussion above after having ReplayGain adjustment applied.
After running both tracks through MP3Gain, the "remaster" (which is in fact heavily compressed) will now sound very slightly quieter than the uncompressed original, as all the transients are flattened on the remastered CD. This can be seen quite clearly in the screenshots.
It is possible that the increasing popularity of digital personal music players, most of which feature some form of volume levelling, will start to reverse this trend.
Popular Examples
Here are some of the more commonly touted examples of excessive loudness-based mastering. These CDs represent some of the most extreme examples of sonic degradation via compression and distortion in popular music:[citation needed]
- ABBA - The Visitors (2005 remaster from Complete Studio Recordings box set)
- Amy Grant - Behind The Eyes, Simple Things, Greatest Hits 1986-2004
- Armor for Sleep - What To Do When You Are Dead
- Audioslave - Audioslave
- Christina Aguilera - Stripped
- David Bowie - Earthling, Heathen, Reality [5]
- Johnny Cash - American IV: The Man Comes Around
- Depeche Mode - Playing the Angel [6]
- Foo Fighters - One by One
- Front Line Assembly - Artificial Soldier
- Iron Maiden - Dance of Death
- John Mayer - Heavier Things [7]
- Kelly Clarkson - Breakaway (title track in particular)
- Oasis - (What's the Story) Morning Glory?
- Queens of the Stone Age - Songs for the Deaf
- Red Hot Chili Peppers - Californication as well as Stadium Arcadium
- Rush - Vapor Trails
- SlipKnot - Vol. 3 (The Subliminal Verses)
- The Stooges - Raw Power
- U2 - How To Dismantle An Atomic Bomb
- Zwan - Mary Star of the Sea
References
- ^ "Loudness" - Loudness is not simply sound intensity" at HyperPhysics
- ^ Loudness Curves at HyperPhysics
- ^ "Loudness and Level Practise at Power House
- ^ "Audio CD Mastering" at ArtMastering.com
- ^ The Death of Dynamic Range at MindSpring.com
- ^ "Declaring an end to the loudness wars" at Barry Diament Audio
- ^ [1]
- ^ "Petition: Red Hot Chili Peppers CD Re-Mastering (Fix Clipping & Compression)" at Doom9 forum
- ^ The Essentials of Fine Audio Recording at DrewDaneils.com
- ^ "Dynamics and Dynamic Range" at StereoPhile
- ^ "Dynamics and Dynamic Range" at StereoPhile
- ^ "What do you all do with LOUD discs?" at Hydrogen Audio forums
See also
External links
- Audio Class With Professor Hoffman - Compression
- The Death of Dynamic Range
- The Big Squeeze: Mastering engineers debate music's loudness wars
- Lindos Electronics Audio Articles
- EBU Recommendation R68-2000
- AES Preprint 4828 - Levels in Digital Audio Broadcasting by Neil Gilchrist (not free)
- EBU Recommendation R117-2006 (against loudness war)
- AES Convention Paper 5538 On Levelling and Loudness Problems at Broadcast Studios
- What is the worst mastered CD?-- Hydrogenaudio Forums
- The Death of Dynamic Range
- AES: An Integrated Approach to Metering, Monitoring, and Levelling Practices
- Vorbisgain