Welcome back for part 2 of our audio deep dive! If you haven’t read it yet, we recommend checking out part 1 first to give it some context…
- Part 1 - Finding the Sound & Implementation
- Part 2 - The Mix & Non-Diegetic Music
In this post, Ross will go into a bit more detail on audio balance and explain his thought process behind the games non-diegetic music.
Oh, and if you like what you hear be sure to check out Star Trucker’s Official Soundtrack. We recently added Ross’s ambient tracks to turn it into a complete collection of all the wonderful music that can be found in the game.
- Monster Dave
The Mix
In the previous post I talked a lot about the sounds of the star truck. While arguably the most important overall, this is only one part of the Star Trucker audioscape.
In the final mix, we need to consider other sounds such as dialogue, music, user interface, foley and truck alert sounds. I generally like to list categories of sounds in order of importance. This can be different for every game but for star trucker we end up with a hierarchy like this:
This kind of exercise can help to give you a solid footing when it comes to defining a structure for the mix. Practically speaking, the way we went about rationalising this prioritised list in the mix is by using volume ducking on various SFX groups using Unity’s audio mixer functionality.
This is set up by sending signals from a higher priority mix group to a ducking plugin on the receive channel of a lower priority mix group. I like to think of this as a cascade of volume ducking where dialogue ducks all SFX and music, critical SFX ducks all other SFX and music, music ducks ambiences and so on…
Using ducking like this can be both a blessing and a curse, and if you’re not too careful you can lose control of the mix by implementing too many dynamic mix behaviours. Less is more is the golden rule here, and it’s often best to use this approach sparingly.
In Star Trucker, I’m also relying on careful placement of sounds within the frequency spectrum to achieve clarity in the mix. For instance, the dialogue processing is designed to emulate squawky CB radio and takes up a very narrow band of frequencies, so it’s easy to carve out space in other sounds to allow that to have it’s place in the overall mix.
Similarly, the frequency profile of the truck is designed to have a lot of energy in low mids, and also some higher frequency detail, leaving some room in the mid frequency bands for other audio like music. I try to keep a mental map of where in the frequency spectrum each category of SFX or music will live during both the sound design and the mix process. In my head it looks something like this:
This is just a rough representation of where the energy of a handful of audio groups would be focussed. In reality there is a lot more overlap in frequency content, but picturing things in this way can really help to inform mix and sound design decisions throughout development.
Non-Diegetic Music
The in-game playlist of music that you hear on the truck hi-fi was one of the first things we worked on at Laced, and we had the pleasure of being able to collaborate with an amazingly talented roster of musicians to make this happen.
All these tracks were written specifically for the game to fit within this universe. As a result, they perfectly set the tone for the game particularly in those immersive moments when the player can just sit back and listen to some tunes on the radio as they’re cruising through space.
It was clear to me during development that there was also room for an additional suite of non-diegetic music that could help support the quieter, more reflective moments of gameplay such as going for a spacewalk to repair your truck or hitching up a trailer for a long-haul delivery.
With this in mind, I couldn’t help but dust off my guitars and commit some ideas to tape...
Functionally, I knew that I wanted this music to sit in the background serving the purpose of breaking up longer stretches of gameplay with some ambient instrumental pieces. The musical palette of country, rock and blues was solidified at this point, so I set about trying to create a number of tracks that would complement the existing music while embracing a more ambient approach utilising mostly characterful guitar sounds with a small selection of other instrumentation like organs and harmonica. Thankfully, having grown up playing blues and country music in various bands, this genre was right in my wheelhouse.
One thing that I drew a lot of inspiration from is the visual aesthetics that Dave and Dan had so wonderfully realised in Star Trucker. I loved how real the truck looked and felt. The truck bears signs of wear and tear with visual scuffs and dings showing a vehicle that has a history of use. In this sense I really wanted to write music that felt quite raw and unpolished in some senses. This approach allowed me to generate a lot of music very quickly, with tracks coming about from quick sketches, improvisational jams and performances often captured in one or two takes. As such, I’d like to think the instrumental tracks are quite human feeling. There were no click tracks, sometimes the guitars were a bit out of tune and there are audible scuffs and dings to be heard if you listen closely.
Once we had whittled down these tracks to a set we were happy with we set about designing a system that managed playback when the game is running. While the tracks do have a certain amount of random probability determining when they will play, we implemented a system that can allow us to more specifically define in what situations the instrumental music can be heard, how often they will play and when they will give way to other higher priority music or SFX.
Signing Off
Wrapping things up I’d just like to say how much of a pleasure and an honour it’s been to work on this amazing little project. Dave and Dan at Monster and Monster have been such wonderful collaborators (we didn’t pay him to say this, honest! - Dave) and I feel very lucky that they entrusted both me and the rest of the team at Laced Audio with the audio for their baby.
For now, keep on truckin’
This is Rosso, clear and gone!
https://store.steampowered.com/app/3088930
https://store.steampowered.com/app/2380050