Huge part of immersion in a motorsports game is the engine sounds. And for snowmobiling, the true enthusiasts have Dolby Atmos and world-class monitors installed in their ear-channels.
The early days
When the original creator, Niko Autio, was still developing Sledders alone, he made the first engine sounds by blowing through his mouth into an empty pea soup can. That was the whole “audio pipeline”. Players did not complain back then. Everyone was just happy the game existed at all.
But none of those sounds were close to a real snowmobile.
When Bonus Stage joined to publish the game, we immediately started searching for real snowmobile sound sources. There are no commercial snowmobile sound libraries. For cars and motorcycles you can buy hundreds or engine sound models. For snowmobiles, nnnope.
Initially we found two companies on the planet that had ever recorded snowmobiles, and those recordings were for movies. Movie audio is useless for games. You can record a sled passing by or doing one acceleration pull, but in a game you need something completely different.
A game needs stable 10-second loops every 500 rpm across the whole rev range. From idle to max rpm. Dozens of precise slices like:
- Idle
- Reverse engage
- Shut down
- Pull start
- Shot start
- 4500 rpm 10 sec
- 5000 rpm 10 sec
- …
- 8500 rpm 10 sec
With these loops we can build a continuous engine model that reacts to throttle input, landing impacts, airborne states, bogging in snow and so on. In a movie, a sound is the same every time you rewind the scene. In a game, the sound must change every single frame.
Winter 2023: our first real recording attempt
When the game had gotten some good traction, engine audio enhancements were really needed. Since there were no professional snowmobile engine audio companies in this world, we decided to FAFO and make them ourselves.
The first order of business was that we bought microphones which can survive 150 dB. Ten centimeters from an exhaust pipe is no joke, so we needed military-grade equipment.
We taped five mics onto a Polaris Khaos 850, got permission from a ski resort in Northern Finland, and spent a full day driving up and down a ski slope recording everything.
After acquiring this full hard drive of recordings, we had to learn audio editing from scratch. From eight hours of recordings we managed to create clean loops of few seconds from all the needed rev ranges. Then we had to learn how to use FMOD and build a functioning engine model from those loops.
These sounds were the ones used when Sledders launched on PC and consoles. Every sled used the same Polaris Khaos 850 with a GGB Quiet Can as a base. Nobody was happy with it. Not us. Not the developers. Not players. But it was still better than the pea soup can "engine". And it was the only option we had at the time.
Why snowmobile audio is so much harder than car or bike audio
First of all, there are two options to record the sounds: ride the snowmobile on snow, or use a custom dyno, which can be used with the snowmobile.
When riding on snow, the sled's track is roaring wildly and it kills most of the engine tone. Also skis create constant scraping noise, while wind noise gets crazy at faster speeds which is needed for basically anything above 4000 RPM.
Removing the belt and revving the sled stationary will pretty soon blow out the engine on the sled, and it does not sound anything like a snowmobile. So because of this a dyno would be needed, but there's very few of those existing, especially in a space with is acoustically sustainable.
Autumn 2025: doing it properly
Finally, after the launch of our self-made audio and people constantly complaining about them, the developers hired a professional audio company from Helsinki. They have worked previously on major productions, including Top Gear Suomi.
This time the idea was not to scream a sled in a parking lot or drive up a ski slope. We wanted dyno recordings.
Paltek in Kemijärvi, Finland builds race sled engines and has a proper engine dynamometer for snowmobiles. With this solution you'll remove the primary clutch and attach the dyno directly to the crankshaft. Then you can “drive” the sled in place while the dyno provides resistance. It sounds exactly like a sled under load on snow.
We moved the dyno outside of the workshop it usually is in, because the indoor acoustics were terrible. We built wind protection using tents, fabrics and cars until the sound environment was good enough.
The audio team placed 12 microphones around the sled. We wanted different sonic profiles:
- 1st person
- 3rd person
- pass-by sounds
- intake
- exhaust
- mechanical noise
The sleds we recorded in the first session:
- Polaris 850 Khaos (GGB and stock)
- Lynx Shredder
- Lynx X-Terrain 900 Turbo R
- Lynx E-Tec 600R Enduro
A not-so-surprise problem came up: cooling. Because this was recorded in autumn, the sleds heated up extremely fast. In practice they would start boiling in two minutes.
The solution was to pile crushed ice on top of the tunnel. We went to a nearby fish factory and bought boxes of ice. It melted over the tunnel and cooled the engine enough to continue. We used multiple full boxes of ice during the session.
We recorded for two full days. Late into the night. It became completely pitch black.
Not a single neighbor complained. They all were actually excited that Sledders was finally getting proper engine sounds. Yeah, everyone in especially northern Finland plays Sledders.
FMOD out, Wwise in
Now that we had a good start on the engine audio, the audio company consulted a major racing game studio. Their advice was clear: move from FMOD to Wwise.
So the whole audio system of Sledders had to be rebuilt from scratch. This took a lot of programmer time and money. But it allowed us to design a more advanced engine model and get higher-quality results. But this change and time pressure, we had to prioritize the base audio first, which caused a temporary removal of one loved element: turbo.
What this really costs
You can imagine this is not cheap. Two audio engineers. Mika from Paltek. Tons of hours from the publisher side. Full professional recording gear. Cars. About 800 km of driving in both directions to the dyno. Accommodation. Food. Ice.
And that is just the recording part.
After that comes editing, engine-model building, coding, Wwise integration, licenses, testing, and mixing.
Where we are now
The long-term goal is to give every sled its own identity. Authentic Polaris, Lynx, Ski-Doo, and also GGB options wherever possible. Players should be able to choose stock or GGB sound profiles when it fits the sled model.
The December 2025 update included the first two new engine sets:
- Polaris Khaos 850 with GGB Quiet Can
- Lynx Shredder (stock can)
These are not final evolution of engine sounds. They are version 1. We will tune them based on feedback, make them fuller, smoother, more dynamic, and adjust mixing for different camera modes. After that, the other sleds will get their authentic recordings too. And yes, TURBO is coming as well, of course.
We have also returned to Paltek to record even more sleds.
How player feedback is used
We want feedback from everyone.
Not all players are snowmobilers. Many have only heard sleds from YouTube videos. A real rider hears the engine completely differently, especially from the driver’s point of view with a helmet on.
So feedback varies a lot depending on what people expect a “snowmobile” to sound like.
That is normal. And we try to balance authenticity with what still feels good and powerful inside a game.
Why we keep doing this
No other developer and publisher is putting this much work into the audio of a niche motorsport game after launch.
Sledders is not a free-to-play title. There is no battle pass generating monthly revenue. When all sledheads have bought the game, income stops.
But we continue improving it anyway, because the game deserves it and the community deserves it. We want Sledders to become the best snowmobile game ever made, and proper engine sounds are a big part of that goal.
We are snowmobilers ourselves. The founder and original creator was an Army Motorcycle Messenger. Asmo from Bonus Stage owned a snowmobile shop in the past. We risk our own snowmobiles engines in recording sessions.
Making engine audio for a snowmobile is insanely hard. But we are not done until it sounds right (enough).