Speed Of Sound Prototype

published Wednesday, 4 May 2011, 14:30 by Kenneth

In my pursuit for achieving "realistic audio", I wanted to try out a simple Speed of Sound Prototype... Do you follow me?... Meek! Meek!

Speed of Sound

One of the first things our Game director, Kim, talked to me about back when I started in Zero Point Software was a simulated "Speed Of Sound-system". Now 2 years and 7 months later I thought it was about time that I actually looked at it :-)

Alright, let's jump right in! The speed of sound is approximately 343 meter per second (m/s) in dry air at 20 degrees Celsius. You know this phenomena from thunder and lightning - as Lighting McQueen says in Cars: "Well, you know, because Thunder always comes after... Lightning!"

Hey... Am I rambling now???... Sorry about that - back to work!

The solution to simulating Speed of Sound is actually quite simple. Just delay the sounds (distance-from-sound-to-listener / 343) seconds. So what does this do to the experience? Well give this prototype a go and let me hear what you think.

Speed Of Sound Prototype
I've exaggerated the delay-effect a bit (by a factor 1.5) to make the it more dramatic (hollywood realism ftw).

Comments

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2 years, 11 months ago

Personally I don't think it adds anything to the game.
The idea is a good one, but would only be interesting when used in a very large, open map. In these cases being shot before hearing it would be useful for the sniper. But for short ranged, fast action games like ISM is turning out to be. I don't think it is really necessary.

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2 years, 11 months ago

i think it sound very realistic, keep up the good work.

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2 years, 11 months ago

I think this too adds something to the realism:) I don't agree with Silverware. You should always look at the little things too and see what you can do to make those bits as realistic as possible, def with sound! because it's such an important element and it's ignored a lot. I'm very glad that you guys are so keen on getting the sound just right!

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2 years, 11 months ago

Aw, no hidden sharkies?

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2 years, 11 months ago

@GortosXtrene - I think that's more Kims departement. I'm a bit more boring... but you never know... ;)

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2 years, 11 months ago

Fantastic work! It's stuff like this in games that make me awestruck. I did notice that, when standing next to the sound, it didn't differentiate between within the line of fire or next to the line of fire (but I'm sure that that would be added later anyway).

In relation to GortosXtreme's comment just replace the impact wall with a sharky and, instead of bullets hitting concrete, replace the wall sounds with meaty ones.

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2 years, 11 months ago

It reminds me of something that happened in a game called 'Frontlines: Fuel of War'.

I was just walkin' along minding my own business when I accidentally shot a grenade off into the distance and noticed a delay in seeing the explosion and the sound reaching me. I then spent the next 10-15 minutes doing this.

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2 years, 11 months ago

I have to admit it was a bit scary when I saw the flashes, heard the ricoches and then the gun itself, just like real life. It's like someone said: Fun stops, this is not a game anymore. Thumbs up from me - small detail but great immersion boost :-)

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2 years, 11 months ago

Oh - forgot to mention that the difference between being in the Line of Fire zone and outside it is, that you hear bulletwhiz sounds inside the Line of Fire zone - to simulate that you are being shot at :-)

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2 years, 11 months ago

Reminds me of playing battlefield 1942. When I was using heavy artillery or a destroyer, the distant impact sound effect did so much to the atmosphere. It was like *only visual explosion far away* *silence* *badoom*. Awesome.

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2 years, 11 months ago

That's a very nice addition as well, in Project Reality they used whizz sounds for tank / apc shells. It enhanced the atmosphere a lot even though it was implemented in a different way (sound source with doppler effect). I can't wait for Deadlock :-)

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2 years, 11 months ago

cool :) think this game will be great :)

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2 years, 11 months ago

I like the idea! Is this a pure sound composition or are you using invisible bullet projectiles? The hits on the wall seems to be instantaneous with the muzzle flash on the weapon.

Good stuff. :)

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2 years, 11 months ago

Sounds AweSOME!!

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2 years, 11 months ago

This would be awesome with a sniper rifle for example

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2 years, 11 months ago

pretty funcky.

Hard to imagine what it will do for the first level in deadlock when it is such a small level. But a good idea to implement this anyway :)

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2 years, 11 months ago

I love it! The delay adds a lot of drama to the perception, which suddenly finding myself on a firing range aptly demonstrates. "So.. where a-" *flashes* "SHII-" *impact*. Much better than when it all happens instantaneously.

I really appreciate you spending considerable effort on modeling audio phenomena, especially as an indie team. It's smart, too. Competing in terms of cutting-edge graphics is hard, but the game audio domain is pretty much starved for innovation. :)

Don't know it if you're reading this, but here's a question:

How well do you find FMOD and Unity support this kind of audio tinkering? Had any problems?

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2 years, 11 months ago

@Serialtinus - the current FMOD integration in Unity is really at its infancy, but I'm being promised that much will happen the next 12 months.

Many of the systems I prototype at the moment are independent from the audio engine.

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2 years, 11 months ago

Leowolf: I think ballistics would be something that goes beyond the scope of this game but something like projectile velocity could be implemented. Muzzle velocities for MP5 are 400 m/s (1,312 ft/s) (MP5A2, MP5A3, MP5A4, MP5A5), 375 m/s (1,230.3 ft/s) (MP5K, MP5KA1, MP5KA4, MP5KA5, MP5K-PDW), 285 m/s (935.0 ft/s) (MP5SD1, MP5SD2, MP5SD3, MP5SD4, MP5SD5, MP5SD6), 425 m/s (1,394.4 ft/s) (MP5/10), 315 m/s (1,033.5 ft/s) (MP5/40). The supressed variants have bullets slower than 343m/s, which means it should be possible to hear the weapon before the impact. Assault rifles have usually something between 700-900 but it can vary a lot depending on the ammo type. If this is implemented then we could hear the ricoches or flybys with the correct delay :-)

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2 years, 11 months ago

There are sharks somewhere here.

Must... Find... Them...

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2 years, 11 months ago

I like the effects of the sound changing across longer and longer distances but I think the impact sound needs a little work as far as different are concerned as well as the sounds that reverberate off the walls( if that's that weird high pitched sound I'm hearing). Keep up the good work!

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2 years, 11 months ago

Great proof of concept. I never liked seeing the muzzle flash and hearing the report of the rifle at the same time for distance shots. It never felt right, especially since I've studied sound a bit. For ease on the game engine you might have to sacrifice that though, but I don't really know.

I would like to say this though, when a bullet passes by in a near miss it makes a crack, not a whiz. What you are hearing is the small sonic boom the bullet is continually making as it passes through the air. A good example of this is the tip of a whip, which is moving faster than the speed of sound. Same goes for a bullet. You would hear a hiss or whiz if it was close, but not close enough to be considered a hit... say ten feet or so away.

Just a thought as far as how sound plays into immersion.

Also, I agree with Claymore, calculating the muzzle velocity of the rounds and adjusting the delays of when you hear the impact, the shot passing, and the report of the gun would be truly immersive, especially for those of us that use our ears as much as our eyes.

In a CQB environment it wouldn't matter as much, but for larger, more open maps, these things could certainly play into it. Also, I would recommend distinctive sounds/tones/timbre's for each weapon.

"What the hell was that?"
"That is the AK-47, sir. It is the preferred weapon of our enemies, and it has a very distinctive sound."
"Yes. Yes it does."

Stuff like that. I know that some companies, like Treyarch do this already, but I don't think they do it well enough. When you have several firearms that sound exactly the same, it can be a pain in the neck. And yes, I know firearms can sound very similar... its just one of those small immersion details to think about.

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2 years, 11 months ago

Wow. I am a real sucker for realism...

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2 years, 11 months ago

I think it adds a lot of atmosphere to the game!!! The light exaggeration is perfect.

Remember to actually POINT OUT such features when doing your tech trailers because despite their impact on immerson, you do not notice the specific feature when not told about it. You just notice that it sounds "realistic", not why.

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2 years, 11 months ago

Something funny is how casual the marine looks when he's firing the gun.

"Oh! What? Oh, this old thing? Yeah, just shooting, you know how it is."

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2 years, 11 months ago

Seems like another small touch that will add to the layers of polish making the game all the better. Good work!

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2 years, 11 months ago

This looks like it could be useful in combat actually, since you wold really hear the direction of the shooter, since the sound from the gun is not mixed with the sound of the bullets colliding with walls. I just hope you take muzzle velocity into consideration because some handguns don't even reach the speed of sound (but you probably knew that already, just making sure :P).

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2 years, 11 months ago

Just adding to what Tearstone said, according to Sebastian Junger's book "War", the sound of a bullet whipping past your head is very similar to a rubber band hitting plastic (I can't remember if it was hard plastic or a plastic bag, but I'm leaning towards hard plastic).

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2 years, 11 months ago

Very cool, first time I can think of that I've seen that in a game. Granted, most of the current stuff we're seeing is indoors and such... but I'm fairly sure that this is only a tiny little fraction of the game, and am willing to bet there will be some nice open air environs where this will be handy.

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2 years, 11 months ago

All you need now is the 'pop' of bullets whizzing past someone and you got yourself as real as it can get 'shot at' effect. x3

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2 years, 11 months ago

Depending of defined variable, I'd assume deaying by multiplying distance with 0.003 (or by 3 and then truncate 3 digits) is better than any division.

Either way if it's no noticeable extra cost on game engine (with many sounds and players), I see no reason not using it.

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2 years, 11 months ago

While, I really can't say I find it all the awesome, it certainly is a nice little realism feature. Cool to see it being added.

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2 years, 11 months ago

As for the conic crack, I found these videos on youtube: [video1](http://www.youtube.com/watch?v=VJFK4SLHig
A "video1"), [video2](http://www.youtube.com/watch?v=J8PuPLIyg9
E "video2") - can anyone who heard it in real life confirm if they are realistic? I don't want to make a silencer for my gun and travel around the firing range with friends begind the trigger :-)

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2 years, 11 months ago

More important than sound delay is ballistics and the whole audiovisual simulation of shooting(that and the mods is why STALKER rules as FPS). You wouldn't gain anything if the bullets were instant like in GTA VC and the sound didn't match the fiction. Good luck finding way to simulate doppler effect, almost no1 done it.

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2 years, 11 months ago

Beautiful stuff man. Works quite well.

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7 months ago

The main thing I dislike about games and sound is the fact that you are instantly deafened
anytime something is launched for the first time. That is what I got from this. :|

All these years with games and they still start off 100% volume, when I think they should
be about 20% and then adjusted higher if need be. Other than my ears bleeding I think
this could be one of those small things that really add to immersion when they game is
complete.

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