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{{Short description|Form of audio post-production}}
'''Mastering''', a form of audio ], is the process of preparing and transferring recorded audio from a source containing the final mix to a ] (the ''master''); the source from which all copies will be produced (via methods such as pressing, duplication or ]). Today, the format of choice is digital masters. Analog masters such as audio tapes are still in use today, although, it looks like the industry is slowly phasing this medium out.
{{Use American English|date=February 2020}}


] was commonly used to create master copies.]]
The source material is processed using ], ], limiting, noise reduction and other processes. The source material is subsequently rendered to the master medium such as CD or DVD. The "mastered" source material is also put in the proper order at this stage. This is commonly called "the assembly or track sequencing". More tasks such as editing, pre-gapping, leveling, fading in and out, ] and other signal restoration and enhancement processes can be applied as part of the mastering stage.


'''Mastering''', a form of ], is the process of preparing and transferring recorded audio from a source containing the ] to a ] (the ]), the source from which all copies will be produced (via methods such as pressing, duplication or ]). In recent years, ]s have become usual, although analog masters—such as audio tapes—are still being used by the manufacturing industry, particularly by a few engineers who specialize in analog mastering.<ref>{{cite web|url=https://thevinylfactory.com/features/analogue-digital-vinyl-mastering-interviews/ |title=What's actually going on when people talk about digital vs. analogue masters|date=18 October 2017 }}</ref>
The specific medium varies, depending on the intended release format of the final product. For ] releases, there is more than one possible master medium, chosen based on replication factory requirements and/or record label security concerns.


Mastering requires critical listening; however, software tools exist to facilitate the process. Results depend upon the intent of the engineer, their skills, the accuracy of the speaker monitors, and the listening environment. '''Mastering engineers''' often apply ] and ] in order to optimize sound translation on all playback systems.<ref name="mixmagazine" /> It is standard practice to make a copy of a master recording—known as a safety copy—in case the master is lost, damaged or stolen.
A mastering engineer may be required to take other steps, such as the creation of a ] (Pre Mastered Compact Disc), where this cohesive material needs to be transferred to a master disc for mass replication. A good architecture of the PMCD is crucial for a successful transfer to a glass master that will generate ''stampers'' for reproduction.


==History== ==History==

===Pre-1940s=== ===Pre-1940s===
In the earliest days of the recording industry, all phases of the recording and mastering process were entirely achieved by mechanical processes. Performers sang and/or played into a large acoustic horn and the master recording was created by the direct transfer of acoustic energy from the wax ] of the recording horn to the mastering ], which was typically located in an adjoining room. The cutting head, driven by the energy transferred from the horn, inscribed a modulated groove into the surface of a rotating cylinder or disc. These ] were usually made from either a soft metal alloy or from ]; this gave rise to the colloquial term "waxing", referring to the cutting of a record. In the earliest days of the recording industry, all phases of the recording and mastering process were entirely achieved by mechanical processes. Performers sang or played into a large ] and the master recording was created by the direct transfer of acoustic energy from the ] of the recording horn to the ], typically located in an adjoining room. The cutting head, driven by the energy transferred from the horn, inscribed a modulated groove into the surface of a rotating cylinder or disc.<ref name=Auld>{{cite magazine |url=http://www.recordingmag.com/resources/resourceDetail/109.html |title=Mastering Then and Now |author=Robert Auld |magazine=Recording |access-date=2016-01-19 |archive-url=https://web.archive.org/web/20171124115019/http://www.recordingmag.com/resources/resourceDetail/109.html |archive-date=2017-11-24 |url-status=dead }}</ref> These masters were usually made from either a soft metal alloy or from ]; this gave rise to the colloquial term ''waxing'', referring to the cutting of a record.<ref>{{citation |url=https://books.google.com/books?id=k_UDAAAAMBAJ&pg=PA47 |title=New Technique Aids LP Waxing |magazine=] |date=1950-03-25}}</ref>


After the introduction of the ] and electronic ] in the late 1920s, the mastering process became electro-mechanical, and electrically-driven mastering ]s came into use for cutting master discs (the cylinder format by then having been superseded). After the introduction of the ] and ] in the mid-1920s, the mastering process became electro-mechanical, and electrically driven mastering lathes came into use for cutting master discs (the cylinder format by then having been superseded). Until the introduction of tape recording, master recordings were almost always cut ].<ref name=Auld/> Only a small minority of recordings were mastered using previously recorded material sourced from other discs.


===Emergence of magnetic tape===
However, until the introduction of tape recording, master recordings were almost always cut ]. Artists performed live in a specially designed studio and as the performance was underway, the signal was routed from the microphones via a mixing desk in the studio control room to the mastering lathe, where the disc was cut in real time.
In the late 1940s, the recording industry was revolutionized by the introduction of ]. Magnetic tape was invented for recording sound by ] in 1928 in Germany, based on the invention of ] by ] in 1898. Not until the end of ] could the technology be found outside Europe. The introduction of magnetic tape recording enabled master discs to be cut separately in time and space from the actual recording process.<ref name=Auld/>


Although tape and other technical advances dramatically improved the audio quality of commercial recordings in the post-war years, the basic constraints of the electro-mechanical mastering process remained, and the inherent physical limitations of the main commercial recording media—the 78 rpm disc and later the 7-inch 45 rpm single and 33-1/3 rpm ]—meant that the audio quality, ],{{efn|Dynamic range was limited by the fact that if the mastering level was set too high, the cutting head might be damaged during the cutting process or the stylus may jump out of the groove during playback.<ref name=Auld/>}} and running time{{efn|Running times were constrained by the diameter of the disc and the density with which grooves could be inscribed on the surface without cutting into each other.}} of master discs were still limited compared to later media such as the ].
Only a small minority of recordings were mastered using previously recorded material sourced from other discs.


===Electro-mechanical mastering process===
===Advances===
From the 1950s until the advent of digital recording in the late 1970s, the mastering process typically went through several stages. Once the studio recording on multi-track tape was complete, a final ] was prepared and dubbed down to the master tape, usually either a single-track ] or two-track ] tape. Prior to the cutting of the master disc, the master tape was often subjected to further electronic treatment by a specialist mastering engineer.
The recording industry was revolutionized by the introduction of ] in the the late 1940s, which enabled master discs to be cut separately in time and space from the actual recording process. Although tape and other technical advances dramatically improved audio quality of commercial recordings in the post-war years, the basic constraints of the electro-mechanical mastering process remained, and the inherent physical limitations of the main commercial recording media — the 78rpm disc and the later 7" single and ] — meant that the audio quality, ] and running time of master discs was still relatively limited compared to later media such as the ].


After the advent of tape it was found that, especially for pop recordings, master recordings could be made so that the resulting record would sound better. This was done by making fine adjustments to the amplitude of sound at different frequency bands (]) prior to the cutting of the master disc.
Running times were constrained by the diameter of the disc and the density with which grooves could be inscribed on the surface without cutting into each other. Dynamic range was also limited by the fact that, if the signal level coming from the master tape was too high, the highly sensitive cutting head might jump off the surface of the disc during the cutting process.


In large recording companies such as ], the mastering process was usually controlled by specialist staff technicians who were conservative in their work practices. These big companies were often reluctant to make changes to their recording and production processes. For example, EMI was very slow in taking up innovations in ]{{efn|In ] each signal input is recorded to its own track on a multi-track recorder. This multi-track tape is mixed down to a mono or stereo master tape. A multi-track tape may be remixed many times, in different ways, by different engineers, giving the possibility of several masters (mono version, stereo version, LP version, AM radio version, single version, etc.).}} and did not install 8-track recorders in their ] until the late 1960s, more than a decade after the first commercial 8-track recorders were installed by American independent studios.<ref>{{cite book|last1=Martin|first1=George|author-link1=George Martin|last2=Hornsby|first2=Jeremy|title=All you need is ears|year=1994|publisher=Macmillan|isbn=0-312-11482-6|page=143}}</ref>
From the 1950s until the advent of digital recording in the late 1980s, the mastering process typically went through several stages. Once the studio recording on multi-track tape was complete, a final ] was prepared and dubbed down to the ], usually either a single-track ] or two-track ] tape.


===Digital technology===
Prior to the cutting of the master disc, the master tape was often subjected to further electronic treatment by a specialist ]. After the advent of tape it was found that, especially for pop recordings, master recordings could be 'optimized' by making fine adjustments to the balance and equalization prior to the cutting of the master disc.
]
In the 1990s, electro-mechanical processes were largely superseded by digital technology, with ]s stored on ]s or digital tape and mastered to ]. The ] (DAW) became common in many mastering facilities, allowing the off-line manipulation of recorded audio via a ] (GUI). Although many digital processing tools are common during mastering, it is also very common to use analog media and processing equipment for the mastering stage. Just as in other areas of audio, the benefits and drawbacks of ] are still a matter for debate. However, in the field of audio mastering, the debate is usually over the use of digital versus analog signal processing rather than the use of digital technology for storage of audio.<ref name="mixmagazine">{{cite magazine |url=http://mixonline.com/recording/mastering/audio_issues_modern_mastering |magazine=Mix Magazine |title=Issues in Modern Mastering |archive-url=https://web.archive.org/web/20070524113354/http://mixonline.com/recording/mastering/audio_issues_modern_mastering/ |archive-date=May 24, 2007 |date=May 1, 2006 |author=Blair Jackson}}</ref>


Digital systems have higher performance and allow mixing to be performed at lower maximum levels. When mixing to 24-bits with peaks between −3 and −10 dBFS on a mix, the mastering engineer has enough ] to process and produce a final master.<ref name="bob_katz"> {{webarchive |url=https://web.archive.org/web/20070827154625/http://www.digido.com/bob-katz/mixing-tips-and-tricks.html |date=August 27, 2007 }}</ref> Mastering engineers recommend leaving enough headroom on the mix to avoid distortion.<ref></ref> The reduction of dynamics by the mix or mastering engineer has resulted in a ] in commercial recordings.<ref name="Shelvock" />
Mastering became a highly skilled craft and it was widely recognized that good mastering could make or break a commercial pop recording. As a result, during the peak years of the ] boom from the 1950s to the 1980s, the best mastering engineers were in high demand.


== Process ==
In large recording companies such as EMI, the mastering process was usually controlled by specialist staff technicians who were conservative in their work practices. These big companies were often reluctant to make changes to their recording and production processes — for example, EMI was very slow in taking up innovations in ] and they did not install 8-track recorders in their ] until the late 1960s, more than a decade after the first commercial 8-track recorders were installed by American independent studios. As a result, by the time ] were making their groundbreaking recordings in the mid-Sixties, they often found themselves at odds with EMI's mastering engineers, who were unwilling to meet the group's demands to 'push' the mastering process, because it was feared that if levels were set too high it would cause the needle to jump out of the groove when the record was played by listeners.
]]]
The source material, ideally at the original ], is processed using ], ], ] and other processes. Additional operations, such as ], specifying the gaps between tracks, adjusting level, fading in and out, ] and other signal restoration and enhancement processes can also be applied as part of the mastering stage.<ref name="Shelvock">{{Cite book|title = Audio Mastering as Musical Practice|last = Shelvock|first = Matt|publisher = ETDR: University of Western Ontario|year = 2012|location = Ontario, Canada|pages = 1–72|url = http://ir.lib.uwo.ca/cgi/viewcontent.cgi?article=1709&context=etd}}</ref> The source material is put in the proper order, commonly referred to as assembly (or 'track') sequencing. These operations prepare the music for either digital or analog, e.g. vinyl, replication.


If the material is destined for vinyl release, additional processing, such as dynamic range reduction or frequency-dependent stereo–to–mono fold-down and equalization may be applied to compensate for the limitations of that medium. For compact disc release, ''start of track'', ''end of track'', and ''indexes'' are defined for playback navigation along with ] (ISRC) and other information necessary to replicate a ]. Vinyl LP and ] have their own pre-duplication requirements for a finished master. Subsequently, it is rendered either to a physical medium, such as a CD-R or DVD-R, or to computer files, such as a ] (DDP) file set or an ]. Regardless of what delivery method is chosen, the replicator factory will transfer the audio to a ] that will generate metal stampers for replication.
===Digital technology===
In the 1990s, the old electro-mechanical processes were largely superseded by digital technology, with digital recordings transferred to digital masters by an optical etching process that employs ] technology. The ] (DAW) became common in many mastering facilities, allowing the off-line manipulation of recorded audio via a ] (GUI). Although many digital processing tools are common during mastering, it is also very common to use analogue media and processing equipment for the mastering stage.


The process of audio mastering varies depending on the specific needs of the audio to be processed. Mastering engineers need to examine the types of input media, the expectations of the source producer or recipient, the limitations of the end medium and process the subject accordingly. General rules of thumb can rarely be applied.
There are mastering engineers who feel that digital technology, as of 2007, has not progressed enough in quality to supersede analog technology{{fact}}, but others, such as Nika Aldrich, a well-known expert in the field, believes that upon close review of the parameters of audio as relevant to human perception, analog recording methods can be demonstrated to be " incapable, however, of recording ''audible perfection''." <ref>Nika Aldrich (2004): Digital Audio Explained]; p. 97 (ISBN 978-1-41-960001-2)</ref>


Steps of the process typically include the following:
== Process ==
# Transferring the recorded audio tracks into the ](DAW)
The process of audio mastering varies depending on the specific needs of the audio to be processed.
# Sequence the separate songs or tracks as they will appear on the final release
Steps of the process typically include but are not limited to:
# Adjust the length of the silence between songs
# Process or ] audio to maximize the sound quality for the intended medium (e.g. applying specific EQ for vinyl)
# Transfer the audio to the final master format (CD-ROM, half-inch reel tape, ], etc.)


Examples of possible actions taken during mastering:<ref name="Shelvock" />
# Transferring the recorded audio tracks into the Digital Audio Workstation (DAW) (optional).
# Editing minor flaws
# Sequence the separate songs or tracks (The spaces in between) as it will appear on the final product (for example, an Audio CD).
# Applying ] to eliminate clicks, dropouts, hum and hiss
# Process or (sweeten) audio to maximize the sound quality for its particular medium.
# Adjusting stereo width
# Transfer the audio to the final master format (i.e., Red Book compatible audio CD or a CD-Rom data, 1/2" reel tape, PCM 1630 U-matic tape, etc.).
# Equalize audio across tracks for the purpose of optimized frequency distribution
# Adjust volume
# Dynamic range compression or expansion
# ]
# Inserting ] codes and CD text
# Arranging tracks in their final sequential order
# Fading out the ending of each song
# ]


==Engineer==
Examples of possible actions taken during mastering:
{{Multiple issues|section=yes|
{{Refimprove|section|date=October 2008}}
{{Original research|section|date=February 2022}}
}}
]s]]
A '''mastering engineer''' is a person skilled in the practice of taking ] (typically musical content) that has been previously mixed in either the ] or ] domain as mono, stereo, or multichannel formats and preparing it for use in ], whether by physical media such as a CD, vinyl record, or as some method of streaming audio.


===Education and experience===
# Edit minor flaws.
The mastering engineer is responsible for a final edit of a product and preparation for manufacturing copies. Although there are no official requirements to work as an audio mastering engineer, practitioners often have comprehensive domain knowledge of audio engineering, and in many cases, may hold an audio or acoustic engineering ]. Most ]s master music or speech audio material. The best mastering engineers might possess ] and production skills, allowing them to troubleshoot ] issues and improve the final sound. Generally, good mastering skills are based on experience, resulting from many years of practice.
# Apply ] to eliminate hum and hiss.
# Adjust stereo "width".
# Add ambience.
# Equalize audio between tracks.
# Adjust volumes.
# Dynamic expansion.
# Dynamic compression.
# ] the tracks.


===Equipment===
The guidelines above are mainly descriptive of the mastering process and not considered specific instructions that may or may not be applied in a given situation. Mastering engineers need to examine the types of input media, the expectations of the source producer or recipient, the limitations of the end medium and process the subject accordingly. General rules of thumb can rarely be applied.
Generally, mastering engineers use a combination of specialized audio-signal processors, low-distortion-high-bandwidth loudspeakers (and corresponding amplifiers with which to drive them), within a dedicated, acoustically-optimized playback environment. The equipment and processors used within the field of mastering are almost entirely dedicated to the purpose; engineered to a high standard, often possessing low signal-to-noise ratios and in many cases, the incorporation of parameter-recall, such as indented potentiometers, or in some more-sophisticated designs, via a digital-controller. Some advocates for digital software claim that plug-ins are capable of processing audio in a mastering context, though without the same degree of signal degradation as those introduced from processors within the analog domain. The quality of the results varies according to the algorithms used within these processors, which in some cases, can introduce distortions entirely exclusive to the digital domain.


]s, phase ]s, and also peak, RMS, VU and K meters are frequently used within the audio analysis stage of the process as a means of rendering a visual representation of the audio, or signal, being analyzed.
== Audio mastering tools ==
{|
| style="vertical-align: top;" |
* ]
* ]
* ]
* Audio Cube
* ]
* ]
* ]
* ]
* iZotope Ozone
* ]
* ]
| style="vertical-align: top;" |
* PYRAMIX Virtual Studio
* SaDiE
* Seqouia
* ]
* Sonic Studio
* Sony CD Architect
* Sony Sonoma
* ]
* WaveLab
* XO Wave
|}


===Aspects of their work===
== References ==
Most mastering engineer accolades are given for their ability to make a mix consistent with respect to subjective factors based on the perception of listeners, regardless of their playback systems and the environment. This is a difficult task due to the varieties of systems now available and the effect it has on the apparent qualitative attributes of the ]. For instance, a recording that sounds great on one ]/] combination playing CD audio, may sound drastically different on a computer-based system playing back a low-] ]. Some engineers maintain that the main mastering engineer's task is to improve upon playback systems translations while the position of others is to make a sonic impact.<ref name="edward_vinatea">{{cite web |url=http://musicmasteringonline.com/understanding-mastering/ |title=Understanding Mastering |last=Vinatea |first=Edward |date=24 April 2010 |website=The Directory of Mastering Studios |access-date=2 February 2018}}</ref>
<references />

Prolonged periods of listening to improperly mastered recordings usually leads to hearing fatigue that ultimately takes the pleasure out of the listening experience.<ref name="stylusmagazine"> {{cite magazine |last=Southall |first=Nick |date=1 May 2006 |title=Imperfect Sound Forever |url=http://www.stylusmagazine.com/articles/weekly_article/imperfect-sound-forever.htm |magazine=Stylus |archive-url=https://web.archive.org/web/20171203075701/http://www.stylusmagazine.com/articles/weekly_article/imperfect-sound-forever.htm |archive-date=3 December 2017 |access-date=2 February 2018 |url-status=dead}}</ref>

===Notable audio mastering engineers===
{{div col|colwidth=20em}}
*]
*]
*]
*]
*]
*]
*]
*]<ref>{{cite news |url=https://www.latimes.com/entertainment/music/la-et-ms-bernie-grundman-mastering-red-bull-20171022-story.html |last=Wood |first=Mikael |title=Bernie Grundman wants to change the way you hear music — for the better |work=Los Angeles Times |date=2017-10-27 |access-date=2020-01-26}}</ref>
*]<ref>{{cite magazine|url=https://tapeop.com/articles/85/steve-hoffman/ |last=Hanlon |first=Keith |title=Steve Hoffman: Mastering The Beach Boys, Miles Davis, & More |magazine=TapeOp Magazine |date=September–October 2011 |access-date=2020-01-26}}</ref>
*]
*]
*]
*]
*]
*]
*]<ref>{{cite news |url=https://www.hollywoodreporter.com/news/george-marino-legendary-mastering-engineer-333020 |last=Barnes |first=Mike |title=George Marino, Legendary Mastering Engineer, Dies |work=Hollywood Reporter |date=2012-06-04 |access-date=2020-01-26}}</ref>
*]
*]
*]
*]<ref>{{cite web|url=http://ericpillai.com/site/|title=Eric Pillai – Future Sound of Bombay}}</ref>
*]
*]
*]
*]
*]
*]
*]
{{div col end}}


== See also == == See also ==
* ]
* ]
* ]
* ]
* ]
* ]
* ]


==Notes==
== External links ==
{{Notelist}}
* A guide to the basics of mastering audio.


== References ==
{{Reflist}}


{{Music production}}
]
{{Authority control}}
]


{{DEFAULTSORT:Audio Mastering}}
]
] ]
] ]
]
]
]
]
]
]
]
]
]
]
]
]

Latest revision as of 16:10, 26 September 2024

Form of audio post-production

Magnetic tape was commonly used to create master copies.

Mastering, a form of audio post production, is the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device (the master), the source from which all copies will be produced (via methods such as pressing, duplication or replication). In recent years, digital masters have become usual, although analog masters—such as audio tapes—are still being used by the manufacturing industry, particularly by a few engineers who specialize in analog mastering.

Mastering requires critical listening; however, software tools exist to facilitate the process. Results depend upon the intent of the engineer, their skills, the accuracy of the speaker monitors, and the listening environment. Mastering engineers often apply equalization and dynamic range compression in order to optimize sound translation on all playback systems. It is standard practice to make a copy of a master recording—known as a safety copy—in case the master is lost, damaged or stolen.

History

Pre-1940s

In the earliest days of the recording industry, all phases of the recording and mastering process were entirely achieved by mechanical processes. Performers sang or played into a large acoustic horn and the master recording was created by the direct transfer of acoustic energy from the diaphragm of the recording horn to the mastering lathe, typically located in an adjoining room. The cutting head, driven by the energy transferred from the horn, inscribed a modulated groove into the surface of a rotating cylinder or disc. These masters were usually made from either a soft metal alloy or from wax; this gave rise to the colloquial term waxing, referring to the cutting of a record.

After the introduction of the microphone and electronic amplifier in the mid-1920s, the mastering process became electro-mechanical, and electrically driven mastering lathes came into use for cutting master discs (the cylinder format by then having been superseded). Until the introduction of tape recording, master recordings were almost always cut direct-to-disc. Only a small minority of recordings were mastered using previously recorded material sourced from other discs.

Emergence of magnetic tape

In the late 1940s, the recording industry was revolutionized by the introduction of magnetic tape. Magnetic tape was invented for recording sound by Fritz Pfleumer in 1928 in Germany, based on the invention of magnetic wire recording by Valdemar Poulsen in 1898. Not until the end of World War II could the technology be found outside Europe. The introduction of magnetic tape recording enabled master discs to be cut separately in time and space from the actual recording process.

Although tape and other technical advances dramatically improved the audio quality of commercial recordings in the post-war years, the basic constraints of the electro-mechanical mastering process remained, and the inherent physical limitations of the main commercial recording media—the 78 rpm disc and later the 7-inch 45 rpm single and 33-1/3 rpm LP record—meant that the audio quality, dynamic range, and running time of master discs were still limited compared to later media such as the compact disc.

Electro-mechanical mastering process

From the 1950s until the advent of digital recording in the late 1970s, the mastering process typically went through several stages. Once the studio recording on multi-track tape was complete, a final mix was prepared and dubbed down to the master tape, usually either a single-track mono or two-track stereo tape. Prior to the cutting of the master disc, the master tape was often subjected to further electronic treatment by a specialist mastering engineer.

After the advent of tape it was found that, especially for pop recordings, master recordings could be made so that the resulting record would sound better. This was done by making fine adjustments to the amplitude of sound at different frequency bands (equalization) prior to the cutting of the master disc.

In large recording companies such as EMI, the mastering process was usually controlled by specialist staff technicians who were conservative in their work practices. These big companies were often reluctant to make changes to their recording and production processes. For example, EMI was very slow in taking up innovations in multi-track recording and did not install 8-track recorders in their Abbey Road Studios until the late 1960s, more than a decade after the first commercial 8-track recorders were installed by American independent studios.

Digital technology

Optimum Digital Levels with respect to the Full Digital Scale (dBFSD)

In the 1990s, electro-mechanical processes were largely superseded by digital technology, with digital recordings stored on hard disk drives or digital tape and mastered to CD. The digital audio workstation (DAW) became common in many mastering facilities, allowing the off-line manipulation of recorded audio via a graphical user interface (GUI). Although many digital processing tools are common during mastering, it is also very common to use analog media and processing equipment for the mastering stage. Just as in other areas of audio, the benefits and drawbacks of digital technology compared to analog technology are still a matter for debate. However, in the field of audio mastering, the debate is usually over the use of digital versus analog signal processing rather than the use of digital technology for storage of audio.

Digital systems have higher performance and allow mixing to be performed at lower maximum levels. When mixing to 24-bits with peaks between −3 and −10 dBFS on a mix, the mastering engineer has enough headroom to process and produce a final master. Mastering engineers recommend leaving enough headroom on the mix to avoid distortion. The reduction of dynamics by the mix or mastering engineer has resulted in a loudness war in commercial recordings.

Process

A common mastering processor for dynamic range compression

The source material, ideally at the original resolution, is processed using equalization, compression, limiting and other processes. Additional operations, such as editing, specifying the gaps between tracks, adjusting level, fading in and out, noise reduction and other signal restoration and enhancement processes can also be applied as part of the mastering stage. The source material is put in the proper order, commonly referred to as assembly (or 'track') sequencing. These operations prepare the music for either digital or analog, e.g. vinyl, replication.

If the material is destined for vinyl release, additional processing, such as dynamic range reduction or frequency-dependent stereo–to–mono fold-down and equalization may be applied to compensate for the limitations of that medium. For compact disc release, start of track, end of track, and indexes are defined for playback navigation along with International Standard Recording Code (ISRC) and other information necessary to replicate a CD. Vinyl LP and cassettes have their own pre-duplication requirements for a finished master. Subsequently, it is rendered either to a physical medium, such as a CD-R or DVD-R, or to computer files, such as a Disc Description Protocol (DDP) file set or an ISO image. Regardless of what delivery method is chosen, the replicator factory will transfer the audio to a glass master that will generate metal stampers for replication.

The process of audio mastering varies depending on the specific needs of the audio to be processed. Mastering engineers need to examine the types of input media, the expectations of the source producer or recipient, the limitations of the end medium and process the subject accordingly. General rules of thumb can rarely be applied.

Steps of the process typically include the following:

  1. Transferring the recorded audio tracks into the Digital Audio Workstation (DAW)
  2. Sequence the separate songs or tracks as they will appear on the final release
  3. Adjust the length of the silence between songs
  4. Process or sweeten audio to maximize the sound quality for the intended medium (e.g. applying specific EQ for vinyl)
  5. Transfer the audio to the final master format (CD-ROM, half-inch reel tape, PCM 1630 U-matic tape, etc.)

Examples of possible actions taken during mastering:

  1. Editing minor flaws
  2. Applying noise reduction to eliminate clicks, dropouts, hum and hiss
  3. Adjusting stereo width
  4. Equalize audio across tracks for the purpose of optimized frequency distribution
  5. Adjust volume
  6. Dynamic range compression or expansion
  7. Peak limit
  8. Inserting ISRC codes and CD text
  9. Arranging tracks in their final sequential order
  10. Fading out the ending of each song
  11. Dither

Engineer

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Mastering engineer Doug Sax with four disc cutting lathes

A mastering engineer is a person skilled in the practice of taking audio (typically musical content) that has been previously mixed in either the analogue or digital domain as mono, stereo, or multichannel formats and preparing it for use in distribution, whether by physical media such as a CD, vinyl record, or as some method of streaming audio.

Education and experience

The mastering engineer is responsible for a final edit of a product and preparation for manufacturing copies. Although there are no official requirements to work as an audio mastering engineer, practitioners often have comprehensive domain knowledge of audio engineering, and in many cases, may hold an audio or acoustic engineering degree. Most audio engineers master music or speech audio material. The best mastering engineers might possess arrangement and production skills, allowing them to troubleshoot mix issues and improve the final sound. Generally, good mastering skills are based on experience, resulting from many years of practice.

Equipment

Generally, mastering engineers use a combination of specialized audio-signal processors, low-distortion-high-bandwidth loudspeakers (and corresponding amplifiers with which to drive them), within a dedicated, acoustically-optimized playback environment. The equipment and processors used within the field of mastering are almost entirely dedicated to the purpose; engineered to a high standard, often possessing low signal-to-noise ratios and in many cases, the incorporation of parameter-recall, such as indented potentiometers, or in some more-sophisticated designs, via a digital-controller. Some advocates for digital software claim that plug-ins are capable of processing audio in a mastering context, though without the same degree of signal degradation as those introduced from processors within the analog domain. The quality of the results varies according to the algorithms used within these processors, which in some cases, can introduce distortions entirely exclusive to the digital domain.

Real-time analyzers, phase oscilloscopes, and also peak, RMS, VU and K meters are frequently used within the audio analysis stage of the process as a means of rendering a visual representation of the audio, or signal, being analyzed.

Aspects of their work

Most mastering engineer accolades are given for their ability to make a mix consistent with respect to subjective factors based on the perception of listeners, regardless of their playback systems and the environment. This is a difficult task due to the varieties of systems now available and the effect it has on the apparent qualitative attributes of the recording. For instance, a recording that sounds great on one speaker/amplifier combination playing CD audio, may sound drastically different on a computer-based system playing back a low-bitrate MP3. Some engineers maintain that the main mastering engineer's task is to improve upon playback systems translations while the position of others is to make a sonic impact.

Prolonged periods of listening to improperly mastered recordings usually leads to hearing fatigue that ultimately takes the pleasure out of the listening experience.

Notable audio mastering engineers

See also

Notes

  1. Dynamic range was limited by the fact that if the mastering level was set too high, the cutting head might be damaged during the cutting process or the stylus may jump out of the groove during playback.
  2. Running times were constrained by the diameter of the disc and the density with which grooves could be inscribed on the surface without cutting into each other.
  3. In multi-track recording each signal input is recorded to its own track on a multi-track recorder. This multi-track tape is mixed down to a mono or stereo master tape. A multi-track tape may be remixed many times, in different ways, by different engineers, giving the possibility of several masters (mono version, stereo version, LP version, AM radio version, single version, etc.).

References

  1. "What's actually going on when people talk about digital vs. analogue masters". 18 October 2017.
  2. ^ Blair Jackson (May 1, 2006). "Issues in Modern Mastering". Mix Magazine. Archived from the original on May 24, 2007.
  3. ^ Robert Auld. "Mastering Then and Now". Recording. Archived from the original on 2017-11-24. Retrieved 2016-01-19.
  4. "New Technique Aids LP Waxing", Billboard, 1950-03-25
  5. Martin, George; Hornsby, Jeremy (1994). All you need is ears. Macmillan. p. 143. ISBN 0-312-11482-6.
  6. Bob Katz Mixing Tips Archived August 27, 2007, at the Wayback Machine
  7. How much headroom for mastering?
  8. ^ Shelvock, Matt (2012). Audio Mastering as Musical Practice. Ontario, Canada: ETDR: University of Western Ontario. pp. 1–72.
  9. Vinatea, Edward (24 April 2010). "Understanding Mastering". The Directory of Mastering Studios. Retrieved 2 February 2018.
  10. Southall, Nick (1 May 2006). "Imperfect Sound Forever". Stylus. Archived from the original on 3 December 2017. Retrieved 2 February 2018.
  11. Wood, Mikael (2017-10-27). "Bernie Grundman wants to change the way you hear music — for the better". Los Angeles Times. Retrieved 2020-01-26.
  12. Hanlon, Keith (September–October 2011). "Steve Hoffman: Mastering The Beach Boys, Miles Davis, & More". TapeOp Magazine. Retrieved 2020-01-26.
  13. Barnes, Mike (2012-06-04). "George Marino, Legendary Mastering Engineer, Dies". Hollywood Reporter. Retrieved 2020-01-26.
  14. "Eric Pillai – Future Sound of Bombay".
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