Speed of Sound?

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KinLM

KinLM

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KinLM
Did searching on this and wasnt able to find anything.. So sorry if there's a thread for this or if this is old news.

But it seems that when you're viewing your car in replay mode or B-spec mode (for instance, you're watching your car using the cameras around the track) and the car gets further away, the sound seems to lag slightly behind the telemetry. Like, the telemetry will tell you that your car shifted gears, and then half a second later you'll actually hear the gear change.

This would seem to replicate the speed of sound in a way. But I don't know if this is on purpose or just an error in the game. Can anybody else clarify possibly?
 
Yes, PD. Unfortunately, it isn't likely for anybody else to give a definitive answer. I'm guessing it was intentional, as it would be odd for the game to do something like that by itself.
 
mistersafeway
Yes, PD. Unfortunately, it isn't likely for anybody else to give a definitive answer. I'm guessing it was intentional, as it would be odd for the game to do something like that by itself.
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That's what I was thinking.. I've never noticed such a thing in a game before.
 
Yeah, that's PD for you: penalties are broken and the AI is nowhere near as good as previous games in the series, but they'll simulate the speed of sound for us! That's why I, along with many other people, love them. :D
 
That's actually realistic. You'll notice the same thing when you're at a real racetrack. You'll often see the car hit the brakes before a corner before you actually hear them let off the throttle. Nothing wrong with it. There's actually a term for it, can't remember what it's called. I'm sure someone will know it. 👍

Edit: Doppler effect?
 
The Doppler effect explains why cars are higher pitched coming towards us than going away, not sure if there's a specific term for this other than the speed of sound. BTW, thanks for mentioning the Doppler effect, it made me think of Sheldon Cooper dressed up as it for Halloween and smile. :)
 
KinLM
That's what I was thinking.. I've never noticed such a thing in a game before.
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The Ace Combat series had it too, complete with tone changes etc. Anyway, the sound engine of GT5 is amazing, the samples just suck. Doppler, echo and speed of sound are extremely well implemented.
 
R1600Turbo
That's actually realistic. You'll notice the same thing when you're at a real racetrack. You'll often see the car hit the brakes before a corner before you actually hear them let off the throttle. Nothing wrong with it. There's actually a term for it, can't remember what it's called. I'm sure someone will know it. 👍

Edit: Doppler effect?
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I call it transmission delay. It's funny, because it's a quite a concern in special relativity (e.g. with regard to viewing fast-moving distant objects, particularly from another fast moving object; they call it the "runtime effect"), and it's almost brain-bending at first to try to visualise, but we probably hear it every day. Whether we notice it is another matter, of course.

This "runtime effect" for sound has been in since GT5:P, where it inspired me to have a crack at it myself. Suffice it so say, they've got some very sophisticated control going on (think about suddenly switching camera and what to do with all that delayed sound you no longer need - not that that's how it works in GT5; only the control inputs are delayed, which is also impressively complex...). I can't actually be bothered to get around that (it requires coding to do efficiently, and I can't be bothered to learn to code properly) so I put up with the wonderful artefacts that changing views produces, and I'm only delaying sound streams, not control inputs! :crazy:

Anyway, sound is delayed roughly one second for every 340 metres travelled, which is about 3 seconds per kilometre, or 4.5 seconds per mile. Noticeable delays are anything above 0.1 seconds, or only 34 metres, so it's not surprising you'd notice it at a circuit (and why it's probably a good idea to include it in your sound engine despite the complexity).
 
^Makes enough sense. To those people wishing that PD had spent more time on the AI than this, I'd rather have this, because (IMHO) I'd rather have a better hotlapper and bad AI than great AI and meadiocre race mechanics.
 
KinLM
Did searching on this and wasnt able to find anything.. So sorry if there's a thread for this or if this is old news.

But it seems that when you're viewing your car in replay mode or B-spec mode (for instance, you're watching your car using the cameras around the track) and the car gets further away, the sound seems to lag slightly behind the telemetry. Like, the telemetry will tell you that your car shifted gears, and then half a second later you'll actually hear the gear change.

This would seem to replicate the speed of sound in a way. But I don't know if this is on purpose or just an error in the game. Can anybody else clarify possibly?
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I don't know about all that.

But i hate the auto clutch in this game.

Though I don't have those problems anymore. I kind of get the jist of what you mean but with a G27 (or any wheel with a clutch) it makes shifting sound realistic to real life
 
But then the HUD display of gears is faster than the actual display and animation of the avatar changing gears. Result lots of unbalanced priories I think.
 
JJSCHMITTY2000
^Makes enough sense. To those people wishing that PD had spent more time on the AI than this, I'd rather have this, because (IMHO) I'd rather have a better hotlapper and bad AI than great AI and meadiocre race mechanics.
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I actually didn't say I'd rather one than the other, just that they took a few hundred steps back on AI. I've been playing since GT1 first came out, so I know what I'm talking about when I say that GT5 probably has the worst AI out of all of them and definitely does when it comes to the difference in tech levels.
 
Unfortunately it seems as though half of the people on this thread have no idea what I'm actually talking about sadly.. But to those who do, thanks for the feedback. I thought it was intentionally implemented but just wanted to make sure that I wasn't the only one noticing this.
 
R1600Turbo
That's actually realistic. You'll notice the same thing when you're at a real racetrack. You'll often see the car hit the brakes before a corner before you actually hear them let off the throttle. Nothing wrong with it. There's actually a term for it, can't remember what it's called. I'm sure someone will know it. 👍

Edit: Doppler effect?
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yes, it is the acoustic doppler effect. (we're doing that now in physics advanced)
 
MonGnoM
yes, it is the acoustic doppler effect. (we're doing that now in physics advanced)
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No, it's the time delay due to the speed of sound not being infinite.



The shockwave travels at the speed of sound.

It's pretty evident here at 23 seconds in:



The brake lights come on, but the car still sounds like it's accelerating.

Doppler shift is related to this delay (in fact, it requires it - Doppler shift wouldn't occur if the speed of sound were infinite), but it's hard to explain the connection in plain English (not that it's hard to understand.)
 
KinLM
This would seem to replicate the speed of sound in a way. But I don't know if this is on purpose or just an error in the game. Can anybody else clarify possibly?
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It also adjusts for time Dialation,
Thats why I always think Im driving so fast, but anyone measuring my lap can see I'm actually going quite slow.
 
PR1VATEJ0KER
It also adjusts for time Dialation,
Thats why I always think Im driving so fast, but anyone measuring my lap can see I'm actually going quite slow.
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Time Dilation...?
 
Time slowing down the faster you go, I think. I'm not so sure about that if that's what he meant or if it's in the game; I've never noticed it, but then again I never noticed the speed of sound in game until you pointed it out.
 
mistersafeway
Time slowing down the faster you go, I think. I'm not so sure about that if that's what he meant or if it's in the game; I've never noticed it, but then again I never noticed the speed of sound in game until you pointed it out.
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You wouldn't notice it, you would need to be going near the speed of light to notice it, or have GT simulate an atomic clock in your car and one of the side of the track.
 
I notice it. IDk why you think its a flaw. PD put the speed of sound the game, more realistic.
 
Exorcet
You wouldn't notice it, you would need to be going near the speed of light to notice it, or have GT simulate an atomic clock in your car and one of the side of the track.
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Studies were done on this actually, and an object 33 centimetres higher went 0.0000000001475784874 (made up number, but all the 0s aren't) seconds faster through time.
 
liampage123
I notice it. IDk why you think its a flaw. PD put the speed of sound the game, more realistic.
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I don't think it was a flaw. I thought it was on purpose, just wanted to make sure that others noticed this and thought it was intentional as well. I think it's super cool that they included it..
 
You know, I never really noticed this. Thanks for bringing this up KinLM.👍
 
KinLM
Time Dilation...?
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Some professional racers call this "the zone" when time truly feels slower to them, they are completely focused on the task at hand, nothing else matters, there is no fear or stress, only confidence and strength and excitement, and the fastest lap times are produced.
 
Doppler effect is the pitch and volume of a sound changing because the distance of the sound source is constantly changing.

Common and very obvious example-moving train blowing it's horn while you're sitting still at the crossing. The sound of the horn appears to pitch up in sound and get louder as the train approaches. after it passes you, your ears perceive the horn as pitching down and getting quieter. That's caused by the constant changing distance of the sound source.

Another example that is a little harder to pick out because it's a constantly varied sound-a racecar speeding toward and then past you. It's just harder to perceive because an engine varies its sound as it gains and loses RPM. The train horn is the same sound and the same tone all the time.

What we perceive at racetracks when we're at one end of the straight and the cars brake at the other and we see the brake lights come on and then hear the brakes and tires squeal, backfires and downshifts about a second later is just commonly called delay.

1130 ft (344 m) per second=speed of sound

Source-I've been an audio engineer for 16 years and was an instructor at an audio school teaching this kind of stuff ;)
 
Thanks to all for their input, I'm glad to see that I'm not the only one who's noticed this about the game, and that it's actually an intentional feature.

Gotta love PD, the game has so many flaws in so many areas, but they'll still implement the speed of sound. That's what makes them different from any other company I guess..
 
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