Dennis Murcia was excited to get an email from Disney, but the thrill was short-lived. As an A&R and global development executive for the label Codiscos — founded in 1950, Murcia likens it to “Motown of Latin America” — part of his job revolves around finding new listeners for a catalog of older songs. Disney reached out in 2020 hoping to use Juan Carlos Coronel’s zippy recording of “Colombia Tierra Querida,” written by Lucho Bermudez, in the trailer for an upcoming film titled Encanto. The problem was: The movie company wanted the instrumental version of the track, and Codiscos didn’t have one.
“I had to scramble,” Murcia recalls. A friend recommended that he try AudioShake, a company that uses artificial intelligence-powered technology to dissect songs into their component parts, known as stems. Murcia was hesitant — “removing vocals is not new, but it was never ideal; they always came out with a little air.” He needed to try something, though, and it turned out that AudioShake was able to create an instrumental version of “Colombia Tierra Querida” that met Disney’s standards, allowing the track to appear in the trailer.
“It was a really important synch placement” for us, Murcia says. He calls quality stem-separation technology “one of the best uses of AI I’ve seen,” capable of opening “a whole new profit center” for Codiscos.
Catalog owners and estate administrators are increasingly interested in tapping into this technology, which allows them to cut and slice music in new ways for remixing, sampling or placements in commercials and advertisements. Often “you can’t rely on your original listeners to carry you into the future,” says Jessica Powell, co-founder and CEO of Audioshake. “You have to think creatively about how to reintroduce that music.”
Outside of the more specialized world of estates and catalogs, stem-separation is also being used widely by workaday musicians. Moises is another company that offers the technology; on some days, the platform’s users stem-separate 1 million different songs. “We have musicians all across the globe using it for practice purposes” — isolating guitar parts in songs to learn them better, or removing drums from a track to play along — says Geraldo Ramos, Moises’ co-founder and CEO.
While the ability to create missing stems has been around for at least a decade, the tech has been advancing especially rapidly since 2019 — when Deezer released Spleeter, which offered up “already trained state of the art models for performing various flavors of separation” — and 2020, when Meta released its own model called Demucs. Those “really opened the field and inspired a lot of people to build experiences based on stem separation, or even to work on it themselves,” Powell says. (She notes that AudioShake’s research was under way well before those releases.)
As a result, stem separation has “become super accessible,” according to Matt Henninger, Moises’ vp of sales and business development. “It might have been buried in Pro Tools five years ago, but now everyone can get their hands on it.”
Where does artificial intelligence come in? Generative AI refers to programs that ingest reams of data and find patterns they can use to generate new datasets of a similar type. (Popular examples include DALL-E, which does this with images, and ChatGPT, which does it with text.) Stem separation tech finds the patterns corresponding to the different instruments in songs so that they can be isolated and removed from the whole.
“We basically train a model to recognize the frequencies and everything that’s related to a drum, to a bass, to vocals, both individually and how they relate to each other in a mix,” Ramos explains. Done at scale, with many thousands of tracks licensed from independent artists, the model eventually gets good enough to pull apart the constituent parts of a song it’s never seen before.
A lot of recordings are missing those building blocks. They could be older tracks that were cut in mono, meaning that individual parts were never tracked separately when the song was recorded. Or the original multi-track recordings could have been lost or damaged in storage.
Even in the modern world, it’s possible for stems to disappear in hard-drive crashes or other technical mishaps. The opportunity to create high-quality stems for recordings “where multi-track recordings aren’t available effectively unlocks content that is frozen in time,” says Steven Ames Brown, who administers Nina Simone‘s estate, among others.
Arron Saxe of Kinfolk Management, which includes the Otis Redding Estate, believes stem-separation can enhance the appeal of the soul great’s catalog for sample-based producers. “We have 280 songs, give or take, that Otis Redding wrote that sit in a pot,” he says. “How do you increase the value of each one of those? If doing that is pulling out a 1-second snare drum from one of those songs to sample, that’s great.” And it’s an appealing alternative to well-worn legacy marketing techniques, which Saxe jokes are “just box sets and new track listings of old songs.”
Harnessing the tech is only “half the battle,” though. “The second part is a harder job,” Saxe says. “Do you know how to get the music to a big-name producer?” Murcia has been actively pitching electronic artists, hoping to pique their interest in sampling stems from Codiscos.
It can be similarly challenging to get the attention of a brand or music supervisor working in film and TV. But again, stem separation “allows editors to interact with or customize the music a lot more for a trailer in a way that is not usually possible with this kind of catalog material,” says Garret Morris, owner of Blackwatch Dominion, a full-service music publishing, licensing and rights management company that oversees a catalog extending from blues to boogie to Miami bass.
Simpler than finding ways to open catalogs up to samplers is retooling old audio for the latest listening formats. Simone’s estate used stem-separation technology to create a spatial audio mix of her album Little Girl Blue as this style of listening continues to grow in popularity. (The number of Amazon Music tracks mixed in immersive-audio has jumped over 400% since 2019, for example.)
Powell expects that the need for this adaptation will continue to grow. “If you buy into the vision presented by Apple, Facebook, and others, we will be interacting in increasingly immersive environments in the future,” she adds. “And audio that is surrounding us, just like it does in the real world, is a core component to have a realistic immersive experience.”
Brown says the spatial audio re-do of Simone’s album resulted in “an incremental increase in quality, and that can be enough to entice a brand new group of listeners.” “Most recording artists are not wealthy,” he continues. “Things that you can do to their catalogs so that the music can be fresh again, used in commercials and used in soundtracks of movies or TV shows, gives them something that makes a difference in their lives.”
