Complex Sound: Car/Motorcycle

[derekderek]

Hi, I am curious about the process of creating a realistic/realtime sampled engine sound for racing games. More specifically, how to create an engine sound that reacts to the acceleration and deceleration of the vehicle. How is this done in major games? I have seen it crapily done in flash games, etc. with basic FM synthesis programming (play wave at A440, increase frequency with acceleration...) But how is this done with sampled engine sounds in games like Need For Speed, etc?

Thanks.

[Will Loconto]

I know of at least two techniques that have been used:

1. A synthesis based engine sound that changes pitch with the acceleration

2. A combination of pitch shifting and crossfading between samples of engine sounds.

Both can give good results but I think #2 is more widely used.

[Waywyn]

yeh, i think no. 2 is more widely used, especially today where you can control a lot of stuff and the performance of a computer can manage it.

on really high-budget games they get the cars into a "recording garage" on special rolls (when you drive you don't move, you know what i mean :))

then they record the car-engine in all gears and do special sounds for acceleration and slowing down.

the only thing i don't know for sure if they only use pitching the sounds up and down or record enough samples to be able to have every speed sound available. so if the player drives around 50 you hear a steady sound and if they player accerelerates from 50-100 you hear the acceleration sample. not sure here.

[His Frogness]

Here's how Greg Hill did it:

http://www.gamasutra.com/features/20021030/hill_01.htm

I haven't done engines yet, but I've thought about it a lot and I think you can incorporate the cross-fading technique rather robustly now-a-days.

I think the amount of time that an engine sound stays constant is rather small. You're usually accelerating or decelerating and only hit a constant speed when you're topped out. So if I were to do an engine sound, I'd have a sample for the top end to cross-fade into, and then use pitch-shifting for the very rare occasion that you're staying constant in mid-band.

For the most part, you're just dividing samples by gear. Accel in 1st, Decel in 1st, etc. What I wonder is if XACT incorporates sample markers. Let's say you downshift from 2nd into 1st, but your RPMs only hit 5k in the process and the "decel_1st_gear.wav" starts at 8k. Can you tell the sound system to start the sample mid-way through, where the RPM's would be at 5K? I would imagine you can do this and that's what I'd look at first. If you could divide one decel sample into every 1k of engine bandwidth, then the entire system would just be: What Gear? What Speed? Accel or Decel?

Then you just have to deal with up and down-shifting samples, brakes, collisions. You'd also have to add the tire screeching, which to me would be more challenging to pull off than engine sounds.

Another crucial decision is the perspective. Do you want it to sound like you're outside the car or inside? I'd vote for inside as I feel it's more immersive. Plus, the outside perspective would require very loud tire screeches relative to the engine sound, which would be annoying. I'm trying to remember if the sounds changed in Grand Turismo when you were replaying your race from exterior cameras. I think they might have.

It was nice to get this off my chest :)

[fabricioz]

Hello,

I'm sound designer and I've just designed the sound for an Stock Car arcade.

I recorded the car engine at various RPM and then sliced it. The game engine will call for 5 files, each one in a RPM, and it will crossfade it as you accelerate and slow down.