Pure vertical layering for game music composers (From Spyder to Sackboy: GDC 2021)

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So happy you've joined us!  I'm video game composer Winifred Phillips, and I'd like to welcome you to the continuation of this series of articles based on my lecture from GDC 2021 - From Spyder to Sackboy: A Big Adventure in Interactive Music!  Using the example of two of my projects from the previous year, I explored the contrasting models of dynamic music design employed in two games - Sackboy: A Big Adventure for PS5/PS4, and Spyder for Apple Arcade.  (Above you'll see a photo from one of the sections of my GDC 2021 lecture in which I'm discussing the Spyder project).  

Both Spyder and Sackboy were developed by Sumo Sheffield and featured whimsical characters and situations.  Each of the two projects had a long list of music requirements and strategies that were dramatically different.  In composing music for these two games, I learned a lot about the flexibility of dynamic music systems.  

Since I worked on music for both games simultaneously, it was fascinating to make comparisons between the two projects after the fact.  Preparing my GDC presentation became an exercise in understanding how flexible video game music can be.  If you haven't had a chance to read the previous two installments of this series, you can read first about Horizontal Resequencing and Song Structure, and then Horizontal Resequencing & Dynamic Transitions.

As we discussed in the previous article, interactive music design is highly contextual. The circumstances dictate our choices.  No single method can be considered the best way, or the right way. Working on these two projects at the same time, I came across this idea over and over again.

Unlike Spyder, Sackboy: A Big Adventure is the latest game in a franchise, and most of the games in this popular series implemented music using pure vertical layering. So that technique will be the subject of our discussion in today's installment of my six-part article series:

For those of us who could use a reminder of the definition of vertical layering, I've included a short excerpt from my book, A Composer's Guide to Game Music:

"In interactive music, vertical layering involves the playing of multiple independent audio files simultaneously within the game’s audio engine, which stacks these layers on top of one another in perfect synchronization. Interactivity is achieved through the independent manipulation of the layers, enabling the overall track to change in accordance with the fluctuating state of the game.

"While this suggests that the game itself has taken on the role of a mixing engineer, we should bear in mind that the composition technique involved in vertical layering is fundamentally different than the process of simply preparing stems for mixing. In making recordings of stems in the audio mixing environment (sometimes known as “stemming”), it is generally understood that in the final result, all stems will be playing together. The composer or audio engineer is motivated by the desire to achieve a good overall mix. However, in vertical layering, the underlying motivation is to create separate audio files that are not always meant to play simultaneously. Instead, they can play in multiple configurations, interacting with the actions of the player as the game progresses."  (Chapter 11, page 194)

When we compose our music so that our chosen instruments in the arrangement can be incorporated separately, and then those instruments can be divided up and manipulated independently during gameplay – that’s the simplest definition of pure vertical layering.  This technique is an awesome way to make music feel reactive, without also having to divide the music into segments.

Sackboy’s previous games in the famous LittleBigPlanet franchise had an elaborate system of pure vertical layering. For a demonstration of how that system worked, take a look at this video that illustrates how a six-layered system can react to the changing circumstances of gameplay within a LittleBigPlanet game:

For Sackboy: A Big Adventure, the music team favored other great methods of dynamic music implementation, foregoing the six layered system that had previously typified the franchise's music strategy. However, Spyder embraced pure vertical layering for its action sequences, so let’s take a look at a few examples.

Our intrepid superspy Agent 8 goes on many dangerous missions.  One of them has him stowing away onboard an enemy bomber plane, putting him in what may have been his greatest peril yet.  I composed a 60s-era spy adventure track with lots of jazz influences for this mission.  As Agent 8 works feverishly to disable the bomber before it attacks, the music adds vertical layers that lend a sense of accomplishment and progression while our hero proceeds in his mission.  There are no horizontal segments, so the vertical layers do all the work to make the music feel dynamic. Let’s see how that functioned.  Notice how simple the music sounds in the beginning, and how it builds in complexity and dramatic heft as multiple layers are added along the way:

In another perilous mission, Agent 8 is charged with stealthily navigating through the innards of a massive computer. The music I composed for this level is a funky late 60s-style track with lots of vertical layers that get activated as Agent 8 moves from one area to another.

Again, there are no horizontal segments, so the vertical layers have to make the music feel reactive to gameplay.  In this case, the music focuses on the location, adding layers as Agent 8 works his way with expert precision into the computer's internal mechanism.

Let's take a look at that:

Much later in the game, Agent 8 gets launched into outer space to rescue some imperiled astronauts. For this level, I composed an interactive 1970s-style space-disco track with vertical layers that react fluidly during gameplay. Sometimes, gamers only hear the rhythm elements of the track – sometimes only the synths – sometimes the whole mix. The vertical layers kick in to control how intense things feel during the game, so let’s check that out:

This vertical layering music from Spyder accomplished two goals: it indicated progress through the level, and it created variety to keep the music from feeling repetitive. So, while horizontal resequencing slices a track up into segments to accomplish the same tasks, a pure vertical layering approach can instill a sense of progression and variety without needing to fragment the composition.
So now we've addressed how the Sackboy franchise previously utilized pure vertical layering, and we've looked at multiple examples of how Spyder employed it. In our next article, we'll take a look at a more hybridized form of dynamic implementation that fuses both horizontal and vertical elements.

Until then, thanks very much for reading! 

Winifred Phillips is a BAFTA-nominated video game composer whose whose most recent project is the music for one of the latest blockbuster releases in the Lineage series (one of the highest-grossing video game franchises of all time). Popular music from Phillips’ award-winning Assassin’s Creed Liberation score is featured in the performance repertoire of the Assassin’s Creed Symphony World Tour, which made its Paris debut in 2019 with an 80-piece orchestra and choir. As an accomplished video game composer, Phillips is best known for composing music for games in five of the most famous and popular franchises in gaming: Assassin’s Creed, God of War, Total War, The Sims, and Sackboy / LittleBigPlanet. Phillips has received numerous awards, including an Interactive Achievement Award / D.I.C.E. Award from the Academy of Interactive Arts and Sciences, six Game Audio Network Guild Awards (including Music of the Year), and three Hollywood Music in Media Awards. She is the author of the award-winning bestseller A COMPOSER’S GUIDE TO GAME MUSIC, published by the MIT Press. As one of the foremost authorities on music for interactive entertainment, Winifred Phillips has given lectures at the Library of Congress in Washington DC, the Society of Composers and Lyricists, the Game Developers Conference, the Audio Engineering Society, and many more. Phillips’ enthusiastic fans showered her with questions during a Reddit Ask-Me-Anything session that went viral, hit the Reddit front page, received 14.9 thousand upvotes, and became one of the most popular gaming AMAs ever hosted on Reddit. An interview with her is now featured as a part of the Routledge text, Women's Music for the Screen: Diverse Narratives in Sound, which collects the viewpoints of the most esteemed female composers in film, television, and games. Follow her on Twitter @winphillips.