Mixing the Fast X Soundtrack with AI Stems

July 25, 2023

Movie soundtracks often carry the same weight for fans as the movie itself. Songs like “Oh Yeah” by Yello or “Danger Zone” by Kenny Loggins will always connect fans back to films like Ferris Bueller’s Day Off and Top Gun, respectively. Famously, fans of the Fast and Furious have also developed deep relationships with songs associated with each of the franchise releases.

For the latest film, Fast X, the franchise tapped Daniel Rowland and Matt Guiler of Immersive Mixers to mix songs on the accompanying soundtrack in Dolby Atmos. Atmos and other spatial audio formats have become the industry standard for blockbuster films due to its ability to immerse audiences in a 360º audio environment.

The first thing to know about spatial mixing and using tools like Atmos, is that you need stems. Stems are required for engineers to isolate and place the different sounds (i.e. drums, bass, vocals) around a listener/viewer.

When Immersive Mixers began working on Fast X, they found they were missing the stems for some of the songs. They were either formatted in a stereo mix, meaning none of the stems were available, or they had the acapella and instrumental, but needed to access the various components of the instrumental — again, stems — so they could properly mix in Dolby Atmos. Fortunately, Daniel and his team were able to use AudioShake to create stems from both these stereo mixes and instrumentals.

“We were able to go in and mix a couple of these tracks that would have been impossible to do otherwise… It’s exciting getting to go back into both new and older catalog music and re-imagine it in new ways. AudioShake has been indispensable for us in doing that. It’s the industry leading technology, hands down.” — Daniel Rowland, Immersive Mixers

In mixing, having access to those individual components makes the difference. Without them, engineers are typically only left with the ability to upmix something and can’t achieve the full potential of immersive audio. Audiophiles and the general viewing public alike know what it is like to be immersed in a scene when the soundtrack can keep pace.

Beyond spatial audio formats, having access to stems can be crucial for a variety of other purposes in the film industry and beyond. Opportunities in remixes and sync licensing, both hinge on having the ability to provide stems.