Every generation brings new innovation to the arts, and music is especially demonstrative of the aesthetic tastes and social themes of a generation, as the form which sees the most prolific production and widest distribution, the fastest evolution and most topical content, of all art forms.

This writeup is not about a single genre of music devised by the Millennial Generation, though microgenres (e.g. Glitch Hop, Vaporwave, Dubstep) are abundant since the advent of synthesizers and digital audio workshops like Audacity, Garageband, and Reaper. It is instead about the unique innovation this generation has applied to preexisting genres, songs, and artists: metamusic, the use of music by other artists as raw material for transformative works, through digital audio manipulation.

First let us address what parameters are used to differentiate metamusic from genre music:

  • Metamusic is never an original composition by the artist producing it. It is always derivative from at least one other work of music, usually by an artist other than the one creating the metamusic. There is certainly "self-metamusic," but this must be distinguished from the artist simply producing several stylistically different variations on the same composition, for simultaneous release to their audience.
  • Metamusic is never a faithful reproduction or "cover" of another artist's original composition. Where a musical cover involves one artist reproducing another's work, usually changing nothing more significant than the instrumentation used or the gender of the lead singer, metamusic always meaningfully alters the fundamental experience of the song.
  • Metamusic is not inherently a parody of the source material. It is usually intended to serve as a sincere standalone musical experience, even if aspects of that experience may still be humourous or mocking in context (since the source material may, itself, be funny or mocking).
  • Metamusic is not constrained to any of the typical parameters of a musical genre: it may feature any instrumentation, any tempo, any atmospheric quality, any performance context, and any number of collaborators and contributors.
  • Metamusic is not constrained to a single nationality, ethnicity, or culture of origin. It is a global phenomenon arising independently from countless artists, in a worldwide act of convergent evolution unique to the Millennial Generation, who have been the first generation to reach adulthood with ubiquitous internet access.
  • Metamusic requires music editing software as part of its creative process, beyond simply mixing and mastering the track to clean up undesired ambient noise, and beyond the use of autotune or other pitch-correction methods. Metamusic is uniquely characterised by the inclusion of this technology, which previous generations could not access, but which has been ubiquitously accessible since Millennials reached adulthood. Any alteration of a song which does not use editing software, is not Millennial metamusic. This is the key distinction of Millennial metamusic from the genre-defying live cover performances of earlier generations.
  • Metamusic requires the source material to be relatively well-known, because metamusic draws on audience recognition of the source material, as part of the musical experience: the interest of metamusic is in its contrastive and transformative nature, from works that are already familiar to the listener. Within this constraint, source material could be literally any song from any era: Mozart mashed up with Michael Jackson is, for example, a popular metamusic premise.

With these parameters established, let us now examine the four dominant varieties of metamusic which have surfaced globally, along with more specific examples of each variety. Let us also refer to these varieties as "transformations," because they are specific types of changes that are applied to preexisting music, not genres unto themselves, even when they appear to have genre-like properties.

Contextualisation

This transformation has two broad subcategories: spatialisation and situation. Contextual music is edited using a Digital Audio Workshop, usually featuring no live-recorded musical performance by the metamusic artist, and it relies heavily on the use of stereo headphones, falling flat if played from freestanding speakers.
Specific Music
Also called specific music edits, place-set music, and "from another room" music, this is a transformation almost wholly invented by the tumblr users Bassiter, Mothman Pseudanthium, and Sound Designer Jeans. Specific music can be either spatial or situational, and most often it is both at the same time. It is also strictly additive in nature: specific music is edited to include sound effects from weather (usually wind and rain), human chatter and ambient noise, mechanical noises (e.g. air conditioners humming in the background), sounds from nature (e.g. crickets, birdsong), or the crackling of a fireplace. It is also edited to feature reverb and sound fading and muffling effects that cause it to sound distant from the listener, or separated from the listener by a wall. The total result of all these various possible effects is the sense that the music is being experienced in a very specific, exact location, while specific activities are occurring nearby, such as sitting outside a lively party, walking through an abandoned shopping mall, a distant thunderstorm, the bustle of a Mom and Pop diner, or a serial killer stalking the listener through a dense forest. Early inspirations of this transformation include the track Eternal (2000) by the band Evanescence and Garth Brooks' 1991 song The Thunder Rolls; both these songs conspicuously feature the sound of thunderstorms in the background of the music, and were popular during the youth of the same Millennials who are now creating specific music edits. Elevator muzak played in public places - especially shopping malls, a staple setting of Millennial teenage social life which has now gone virtually extinct - is another influence of this transformation, and it also partly inspired the Vaporwave genre of Millennial-produced electronic music.
Directional Music
Also called 8D audio, ambisonic music, or binaural sound, directional music is a spatial transformation which relies on manipulation of the subjectively perceived local position of the source of sound, moving it around constantly between the left and right speakers, as well as making complex panning and zooming changes to the position of the sound source. The resulting effect ranges from making the listener feel they are in the middle of a live performance, to making them feel as though the band is swooping around their head at a frantic pace, or the lead singer is right behind them, leaning over their shoulder. This transformation is closely related to the ASMR genre of recordings, and the principles and techniques of directional music are applied extensively by the most popular ASMR artists.
Without Music
More a transformation of music videos, than a transformation of the music itself, this is a form of situational transformation, sometimes (but not always) played for comedy. It is when a music video has its original music stripped out, and the video is then subjected to one of several possible treatments: in comedic instances, mundane sound effects may be dubbed into the video, such as the squeak of backup dancers' sneakers, or someone coughing in the background. In other instances, a different song may be dubbed over the music video, or the same song may be dubbed onto the original video, with another transformation applied to the song, resulting in a change in how the video is interpreted psychologically by the viewer. This transformation is inherently reliant on the visual medium, and does not exist as audio-only tracks.

Mashup

A descendant of remixes, a mashup or sound collage is any transformation of two or more songs that causes them to seamlessly fuse with each other into a single coherent resulting song. Mashups are not consecutive mergers of multiple songs: there is not a section of one song, followed by a section from the other. Instead, mashups separate the various instrumental and vocal tracks that make up each song, and recombine them so that, for example, the vocals of song "a" are layered with the instrumentation of song "b," or the vocals of both are performed simultaneously while preserving the clarity of each. Mashups may use music that has already had another transformation applied to it, such as a specific remix of a song being used as a source track, instead of the original version. A mashup may require the key, mode, and beats per minute of a source song to be manipulated, before it can fuse with another source song; mashups do not have to stay faithful to the source material. Importantly, the quality of a mashup is informed not just by its execution, but by its audience's familiarity with the source songs. An ideal mashup is one which sounds more "complete" than either source song, such that listening to either source song on its own sounds flat or "missing something" in the perception of the listener. Mashups use naming conventions that fuse the titles of the source songs, e.g. "Sweet Dreams for the Summer" is a fusion of Sweet Dreams by Eurythmics and Cool for the Summer by Demi Lovato, while "Into Stranger Things" is a fusion of the Stranger Things title music and Into You by Ariana Grande. A song does not constitute a mashup if it only samples a small portion of one track, to add to another track. That would still fall under the definition of a remix. There is such a thing as a "live mashup," such as those created by The Piano Guys, but this is understood to be an acoustic reverse-engineering of what is fundamentally a digital transformation, and not the other way around.

Dramatic Cover

A transformation overlapping definitions with the pan-generational metamusic called genre-bending, this transformation is the only one which inherently entails a newly recorded performance from the artist who is creating the metamusic: every dramatic cover requires some complete overhaul of the instrumentation or vocals of the source material. While it is plausible that a Digital Audio Workshop could be used to create these effects wholesale from the source material, without the metamusic artist ever needing to pick up a microphone, it is usually much easier to just make an original recording instead. As such, dramatic covers typically involve the artist having established skill as a singer or instrumentalist, and quite often they will have many contributing performers, not just a single sound designer working from a DAW and some source tracks. What distinguishes a dramatic cover from a typical song cover is that it comprehensively reinterprets the source material: the genre, emotional mood, key and mode, instrumentation, and even the apparent ethnic origin of the music, are completely altered away from the original version of the song. Any genre-bending of a song - provided sound editing software is employed for the transformation process - may qualify as a dramatic cover, but if the emotional content of the song is not altered somehow, it is not typically considered a dramatic cover, only a genre-bend. Genre-bending very likely predates written language, as it would have been possible from the advent of at least two genres of music, between which to transform songs, so it is important to distinguish dramatic covers by both their necessary technology and their necessary emotional content.
Cinematic Cover
Also called emotional cover, this transformation brings a full symphony orchestra of instruments (usually synthesised) and a single (usually female) vocalist, to take an otherwise straightforward song and make it as emotionally dramatic as possible. The overt goal of this transformation is to wring significant pathos from songs which otherwise completely lack it. Though this is rarely used to comedic effect within the songs themselves, cinematic covers are generally viewed as humourous in the abstract - postmodernism applied to the point of absurdity - while fully serious and sincere in execution.
Epic Cover
Sometimes labeled "battle" or "boss fight" music, epic covers are usually strictly instrumental or have truncated lyrics, and they evoke a dynamic sense of conflict and urgency, such as in the soundtrack of action films. Epic covers primarily use a full orchestra of instruments, though these are usually produced through MIDI sound fonts, and not by getting an entire live orchestra of musicians together to record the tracks used. Epic covers also often feature electronic sounds, and they may feature a slow build up to a "drop" like what is found in Electronic Dance Music (EDM).
Atmospheric Cover
This transformation converts musically complex, attention-grabbing songs into synth-intensive, heavily blended music, stripping layers of instrumentation away to produce music that makes it easy for the listener to "zone out" or focus on schoolwork without being distracted by the music. Lyrics are often also stripped away, treated as a distracting element.
Dark / Light Version
A dark version of a song is transforming an otherwise-upbeat piece of music into one that sounds threatening, like music found in horror film soundtracks. A light version reverses this process, reinterpreting depressing or ominous music into something ethereal and soothing, often involving the inclusion of a "heavenly choir" audio effect. Unlike Cinematic Cover, these transformations tend to use minimal instrumentation, instead creating tension or serenity through the use of a single vocalist (usually a soprano) with heavy reverb added, and two or three distinct musical instruments, one of them usually a synth pad.
n-Bit Cover
Related to chiptunes and other video game music, and usually labeled 8-bit and 16-bit music, etc., these transformations are a complete reinstrumentation of a song so that it sounds like part of a video game soundtrack. Importantly, this is not simply a genre rebranding of the song; it is also a reinterpretation of the mood of the song, to the point of converging on Specific Music: a cheerful pop song may be reinterpreted as the music to a final boss battle or fighting game theme, while a love song may be converted into water level music from a platformer.

Shifted Music

This transformation entails speeding up, slowing down, and pitch-shifting a song. The shift may be applied to the entire song, a single instrument or voice, or even a specific set of pitches singled out from the rest of the melody.
Nightcore
Named after the Norwegian pitch-shifting artists of the same name and originating in 2002, Nightcore music is tempo-shifting a song so it plays back at least 25% faster than the source material, resulting in the song also playing at a much higher pitch than the unaltered version. This tends to cause even very somber music to sound manic and cheerful, even cartoonish. Nightcore versions are typically only done for songs that have a vocal performance; strictly instrumental music does not receive this treatment. This transformation typically has an end goal of producing dance music suitable for a night club, around 160 beats per minute, even (or especially) if the source music was not suitable for dancing.
Daycore
Also called "Lightcore," Daycore is the opposite operation of Nightcore: slowing a song by at least 25%, resulting in a lowering of pitch and a heavy, ominous, even menacing sound. Unlike Nightcore, Daycore is frequently applied to instrumental music, and in such cases it converges on the "Dark Cinematic Version" transformation. The distinction between the two is that Shifted Music does not alter the actual instrumentation of a song, and is not a newly recorded performance of a prior song by a later artist: it is strictly transformed in a DAW. Daycore music also includes EDM slowed below 80 bpm so that it is no longer serviceable for dancing. With this in mind, the "day" element of labeling is both ironic respective to the tonal darkening of the music, and sensible at establishing the music is opposite the purposes of dance-focused night clubs.
Genderbend
Genderbending is altering the pitches of a song higher or lower, sometimes by an octave or more, so it plays out in a masculine or feminine vocal range, opposite the vocal range of the song's actual lead singer. Typically this is done without altering the playback speed of the song. Genderbent songs are typically listed as "Title Female Version" or "Title Male Version."
Modal Shift
The simplest example of this is shifting a song from a major key into a minor key, or vice-versa. A modal shift is the selective pitch-shifting of individual pitches, across an entire song, or across individual sections of the song (e.g. verse, chorus, bridge), to change its musical mode, and consequently its emotional tone. Note that mode-shifted cover performances of songs have existed for as long as modes have existed; modal shifting as Millennial metamusic specifically refers to the digital manipulation of the song track to produce this effect.
Iron Noder 2019, 8/30