Introduction – About ROM: Extraction
ROM: Extraction is an arcade-like shooter for VR set in a fictional futuristic world that has you taking on the role of an extraction specialist. As a soldier assigned to harvest little orbs harnessing immense amounts of potential energy, your progress unexpectedly comes to a hault as you’re tasked to defend the area until you can be extracted to safety. This is the core game loop that the player will experience, but to create an effective music system we must take into consideration the following things: Game Flow/Path, Tone/Mood, and Technical limitations.
Here is a teaser trailer for the game that was just released:
Designing a Music System for ROM:Extraction
First, let’s discuss game flow which in this case refers specifically to a player’s initial experience with the game. Before a player gets to the core game loop they will encounter a variety of different “mini-experiences.” The image below accurately captures the typical flow of a player’s initial run through ROM: Extraction.
You may be wondering why I’ve taken into consideration the flow of the player’s movement through different “mini experiences”, as music systems are usually derived from and contained within a single larger experience. The answer is because while our core game loop is highly re-playable, it’s also relatively short and the “mini experiences” (before and after) the core loop are then much more important because they will be visited frequently.
A gameplay session will typically last between 5 – 20 minutes depending on how many times the player wishes to repeat the core game loop and if they want to revisit the tutorials. After the player’s initial game, if they wish to play again, they have incentive to not only beat their high score, but land on both local and global leader boards.
Now that we have a solid understanding of our game’s flow, it’s critical to determine the tone for not only each “mini experience” the player will encounter, but the entire game itself. Wisely, as ROM grew out of a handful of unique gameplay mechanics, Hess Barber (President of First Contact Entertainment), decided the first piece of music should be catered to the intense gameplay. He discovered that a dubstep-like track with futuristic electronic elements helped enhance the excitement of the core game loop. As this was a little bit before I officially joined the project, Twin Moons (the dubstep alias of EDM artist Le Castle Vania) was commissioned to create a fantastic piece of music for this aspect of the game.
However, as anyone who’s listened to dubstep knows, that style of music is super intense and gobbles up most of the frequency spectrum. So for many of the “mini experiences” it just wouldn’t have been appropriate. Furthermore, as the art and animation progressed it became evident that something a bit dark and even mysterious would befit other elements of the game.
Knowing this, we asked for stems of the original piece composed by Twin Moons. From this material I derived the rest of the music for the game. I processed a variety of the musical stems in unique ways to twist it into something more befitting of our “mini experiences” and composed additional material (mostly harmonic/melodic) to help sell the new mood we were aiming at. While stylistically (and intensity-wise) the music can vary greatly in the game, by using processed material from the main gameplay track throughout the score in unique ways and keeping a consistent harmonic palette that sticks strictly to a 150bpm tempo (or equal subdivisions thereof) we were able to create a cohesive musical score.
**In the Main Menu track you can hear elements of an arpeggiated figure from the main gameplay loop (with Tremolo & other FX) and Percussion (Half Time with Delay and FX).
Last, but most certainly not least, we had to take into consideration our current technical limitations for the project. Audio middleware was not an option for ROM: Extraction’s initial release; fortunately though, I was pleasantly surprised with the current tools and functionality of Unreal 4’s audio system. From the beginning I knew that the score wasn’t going to be highly interactive, as other audio elements like V.O. would take that role, and instead the music should “paint broad strokes” that enhanced each “mini experience” while changing to the appropriate mood. So with this simplified approach in mind we were easily able to implement everything we needed within UE4. Most of the “mini experiences” only needed simple looping functionality and stingers or sound effects to help mask fade in/out transitions. The most involved system was designed specifically for the core gameplay loop and it consisted of the following.
As you can see from the image above, the primary music the player will hear is the main gameplay loop; however because the player can manipulate time (and the music responds accordingly), they may encounter some really cool and somewhat un-intentional results. Happy little accidents that we planned for in the system, yet the number of unique “accidents” a player might encounter is infinite. This is because coupled with the music, the sound design responds to time manipulation and was created to blend together nicely with it. Explosion sounds aren’t just simple “booms,” but E.M.P. like pulses that stretch digitally and make you ask, “Was that part of the soundtrack or the orb explosion sound?!”
Although it wasn’t mentioned at the beginning of the article, I feel like it’s important enough to talk about now. Mixing. VR gives us the option to do some very interesting things with music and for some projects it’d be great to pan instruments below, behind, and/or surrounding the player in unique ways. However, for ROM: Extraction we felt it was more important to have the player be aware of sound locations and just let the music act as mood or momentum. With that in mind, we decided to keep it traditionally stereo while EQ’ing a bit of room for SFX, although we tried other options before settling on this.
When it was all said and done we had about 3 to 4 minutes of music split into various mixes and implemented in a way that extended their typical “lifespan.” I expect that future VR games will present me with unexpected challenges and I look forward to experimenting with interactive music systems that fully take advantage of head tracking and pin-point spatialization. Thank you for reading and I hope you learned a bit about the way we scored ROM: Extraction. Hopefully this new knowledge will be useful in your own work!
**Quick shout out to everyone on the team who’ve been working very hard & have helped me out. Especially to Ian Kowalski who helped implement the system and Hess Barber for both his creative ears and bringing it all together.
About the Author
Kole Hicks is a LA based Composer and Sound Designer who’s work can be heard in PC games like Pixel Piracy, Kenshi, & Armored Warfare. Beyond creating audio for games, Kole provides session guitar work, has performed as guitarist for multiple touring bands (Critical Hit & Olivia Somerlyn), and is an accomplished writer of music articles having been nominated for a GANG award in 2012. Furthermore, Kole is an active member & proponent of the Game Audio community with experience speaking at UCLA, The Art Institute, GDC 2015, and Game Sound Con.