No Stupid Questions @lemmy.world red_pigeon @lemm.ee 2 days ago

How are engine sounds in racing games played ?

For example in forza, the game plays engine sounds based on how much we press the button. Are there different sequences of clips ? If yes how do they blend so well ? Or are they synthesized dynamically ?

There are so many parts to it as well - when the gear shifts, when you suddenly slow down at high speed, when you suddenly accelerate from stop. They all seem very realistic.

Edit: Thanks for the great answers everyone 🙏

31 comments

Most older games will have 2-3 engine loops that they will blend between and pitch accordingly, however Forza 5 specifically was the first in the series to use granular synthesis which is a much more modern approach.

These will have a series of sound files including all the different parts of the engine, exhaust, turbo, etc. Then the software slices these files into tons of pieces in real-time and plays the slices based on the players inputs.

It’s tricky to explain without examples, so here’s a video that does a decent job of explaining how it works in music: https://youtu.be/ftDLRYnRYZQ?si=SEHOl55K7rimi4Eu
- Some electric BMWs do the same on the literal automobile, too. It's an EV that sounds like a high performance ICE both inside and outside the car.
  
  Can you buy different sound packs? I would want mine to make a "wub wub wub" sound...
I made changing farting sounds in my game Diarrhea 4 by manipulating the pitch. I bet that's how they do it in racing games as well.
- Holy shit. OP surely delivered.
- LOL great job on the background music
  
  That was a very lucky find! I think I found it when looking for fart sounds until I opted to make them myself.
  
  I really gotta find the energy to add some credits. Every asset is free of attribution, but still.
- What about Diarrhea 1-3?
  
  He's pulling a star wars
  
  Don't forget about Diarrhea Zero and the next gen remakes for 1 and 2. Also, there's the ARG in the DFW airport bathrooms back in the early 00s. There's also the previous series Diarrhea is based on, The Skids.
- I need to kiss you.
It's certainly simpler than Forza et al, but there's an open-source racing simulator, called Speed Dreams: https://www.speed-dreams.net/
If you watch the "Latest Release" video, there's some engine sounds in that.

They seem to have a bunch of samples for how different car models' engines sound: https://sourceforge.net/p/speed-dreams/code/HEAD/tree/tags/2.3.0/data/data/sound/

And then they modulate that in code, based on the car's speed, gear, turbo etc.:
https://sourceforge.net/p/speed-dreams/code/HEAD/tree/tags/2.3.0/src/modules/sound/snddefault/CarSoundData.cpp#l171

They also do that for gear changes, tyre sounds, collisions and backfires.

From what I know about audio, I would expect AAA games to still use the same approach of recordings+modulations.
While it is possible to fully synthesize an engine sound, it doesn't help you much with making it sound right in all different situations.
I’m not sure about Forza, but check out This guy. He makes out great engine simulation sounds that are close to real life counter parts
- Wow this is really cool. Thanks
  
  https://www.youtube.com/watch?v=RKT-sKtR970&t=309
  
  This is kinda similar, just neat to me. https://youtu.be/mg-Aa11wqeY?si=NrNDIWa5Gw5WS6Jz
Nowadays, it is exactly as complex as it sounds. There is a ton of blending, pitch and playrate tweaking, separate modifiers for current rpm and how much the accelerator is currently depressed. And yeah, like hundreds of recorded samples from the real car when possible, or a similar sounding car when not possible.

We are probably on the verge of getting to a point where a rough simulation might soon be able to take over for this process. It won't sound as good for a while still, but it will be cheaper and faster soon. And as time goes on, it'll get close enough to sounding right while continuing to decrease in cost and time taken to a point where it'll be the only way to do it eventually
- I've had the thought of using a video game engine synth for electric cars. all of my neighbors have evs and they are so freakishly quiet and I've almost walked into them a few times when leaving through the alley while being a phone zombie
  
  Most EVs actually play sounds already. Just older ones wouldn't now. My brother set his to a spaceship sound. But you can pick normal sounds too, like various style ICE engine sounds.
  
  EV drivers are legally obligated to get an 18 inch sub and crank it.
  
  I remember there was the possibility in the talks to mandate some sound on EVs. I think Tesla wanted to use the sound of Blade Runner cars.
Different studios take different approaches, I know when Polyphony digital was making Gran Turismo 7 they dramatically changed how they were doing audio by actually bringing the real cars into a dedicated recording studio. This isn't the video I saw a few years ago, but it's similar.

To my knowledge they may have been (still?) the only studio doing it this way.
- SCS, devs for Euro Truck Simulator 2, records sounds from the actual vehicles as well.
There is also a one man wonder effort to improve the sound work of simulated engines by "simply" simulating the flow of air https://www.youtube.com/watch?v=J11c8mMN1PA
I remember exploring the Road Rash files as a kid and each bike sound was a single short click that just repeated rapidly. Times have changed.
- All sounds are short clicks that just repeat rapidly, if you think about it.

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