Hello ! I don't know if this is the right place to ask, but i will try... I must sample an aircraft engine sound. I got a cd with the engine running at idle, low rpm, accelleration, and full rpm. Ok, what is the problem ? the problem is that i must create a looping sound for every throttle position, so i've tried to extract a portion of the sound during the accelleration and to repeat it in a loop... but i can't get a costant sound to simulate the engine running at the same rpm. And even, i'm not sure that i must sample every throttle position... i think that with the pitch control i can simulate an acceleration or deceleration right ? But what's better to sample ? the engine in idle mode and the upgrading with the pitch, or the engine at full throttle and downgrade with the pitch ? Anyone know where to find somewhere on the web or in a book, how the professional game programmers will do that ? i mean simulate an engine, aircraft, car, bike... it's all the same... into the game you can accelerate a little, then go with a costant sound, then accelerate again, then decelerate... i don't think they have recorded every single rpm right ? Thank you for your help ! regards David

What I've done for some car games is record samples at all gears. So ten seconds at Neutral, 1st, 2nd, 3rd, 4th, 5th. So I have 6 levels of engine activity. Within those gears it sounds ok for the audio engine to pitch it up and down. I wouldn't really ask the audio engine to pitch bend the samples more than a few gears anyway , so you can get away with less gears (zones) sampled but be careful.

And generally speaking, you want the program to mostly pitch your samples up, but some audio engines have sounded impressive bending both ways. That also depends on the quality and characteristics of your original sample.

Bare minimum you want an idle loop (unless the vehicle never is at idle), an in gear loop or two and let the program have at it, results vary. Though that sound from an idle engine to 1st gear is not something you want to typically let the pitch bend handle. Try and sample it yourself and throw it in as an intermediary "zone" in the chain.

Ideally you want ignition, idle loop, idle to first gear accelleration (non-looping segue), 1st gear, gear shift sound, and each accompanying gear you need after that.

Though, looking back at a lot of racing games, they cheat and get by with just one zone or two of in-gear revving and just throw in the clutch sound at intervals predetermined by speed. That works too if your samples can handle it. Usually an engine in first gear will sound thin and whiny when you "speed it up" to high. And an engine at a higher rev pitched down to 1st will start creating artifacts and aliasing issues before they become useable.

This is all from my experiences, so others may have gotten more lucky, but I find the most accurate way of reproducing engines is to accurately reproduce them gear by gear, nuance by nuance.

Of course that all depends if you are handling integration or not!

Tony

Hi,
I have done quite a lot of recording, editing, and programming of sounds for flight simulators.

Ideally you should have several seamless looping sounds, I usually try to have at least 3 (idle, medium, & maximum thrust) and use the pitch shifting of the game engine to blend them together like you described. But it is always a compromise between sound quality and file size.
If you used only one loop and simulated acceleration just usng pitch shifting it would probably sound very odd.
It makes sense that pitch shifting a sound upwards would sound better than downwards, but I have never really noticed a huge difference in quality using Microsoft FS.

Creating a seamless loop is very easy if you have a decent recording to start with and the right tools, what software are you using?

[Edited by - Haydn on January 16, 2007 11:20:14 AM]

Thankyou anthemaudio for your reply,

you was enough clear to understand :-)


I don't have to create samples from a car engine but from an Aircraft engine, so no gear-change problems eheh.

The problem for me is : Take for example an aircraft starting up and running at idle, then the pilot give some throttle (say..30%), and the engine must run constantly in a loop at this rpm, then the pilot give throttle at... 60% for example, and the engine must run at this rpm still looping.. and so on until full throttle.
I have an high quality cd with the sound of the idle, acceleration until 80% throttle, and a fast fly-by at full throttle where i must try to extract a portion of sound to make a looping sound.

I don't know if there is techniques other than playing with pitch.. but if there's something, i ask your help and suggestions :-)

P.S: sorry for my bad english..

regards
David

Quote: Original post by Haydn
Hi,
I have done quite a lot of recording, editing, and programming of sounds for flight simulators.

Ideally you should have several seamless looping sounds, I usually try to have at least 3 (idle, medium, & maximum thrust) and use the pitch shifting of the game engine to blend them together like you described. But it is always a compromise between sound quality and file size.
If you used only one loop and simulated acceleration just usng pitch shifting it would probably sound very odd.
It might sense that pitch shifting a sound upwards would sound better than downwards, but I have never really noticed a huge difference in quality using Microsoft FS.

Creating a seamless loop is very easy if you have a decent recording to start with and the right tools, what software are you using?

Hi Haydn, thank you for your reply.

this is exactly what i need.
I have an high quality CD with sound of various aircraft, the only problem is the full throttle that is a fly-by... you know.. not a costant sound and i have problems trying to extract only few seconds to make a looping (until now the result is a looping sound that varies intensity..i can't describe with words..)

The software i have to edit audio files are :
- Nero Wave editor (lol)
- Sony Soundforge 7

I use soundforge to test the realtime pitch shift.

There is some better software for this things ?

Thankyou, regards
David

Hi,
Soundforge is great, it is definitely suitable software for this.

The method I use to get seamless loops is;

1. Find a section of audio that is reasonably constant in pitch and tonal characteristics, maybe a few seconds.

2. Cut this audio clip in the centre and place the first half of the clip after the second half.

3. Join the two clips together with a crossfade, and adjust the parameters of the crossfade till it sounds good to you!

This will probably work very well with the constant engine RPM sounds you have, but it might not be easy to get a good sound from the flypast, because you probably wont have a continuous section of the recording that doesnt change pitch or volume much.
The only aeroplane I have been able to get /really/ good constant engine sounds at max RPM from is the harrier, because it can hover.

I also use automatic pitch control effects (autotune) when creating these loops which locks the pitch of the audio to 1 'note', but I dont know if sound forge can do this.

Quote: Original post by Haydn
Hi,
Soundforge is great, it is definitely suitable software for this.

The method I use to get seamless loops is;

1. Find a section of audio that is reasonably constant in pitch and tonal characteristics, maybe a few seconds.

2. Cut this audio clip in the centre and place the first half of the clip after the second half.

3. Join the two clips together with a crossfade, and adjust the parameters of the crossfade till it sounds good to you!

This will probably work very well with the constant engine RPM sounds you have, but it might not be easy to get a good sound from the flypast, because you probably wont have a continuous section of the recording that doesnt change pitch or volume much.
The only aeroplane I have been able to get /really/ good constant engine sounds at max RPM from is the harrier, because it can hover.

I also use automatic pitch control effects (autotune) when creating these loops which locks the pitch of the audio to 1 'note', but I dont know if sound forge can do this.

Hi ! Thank you for your help, tomorrow i'll try this trick.

Can i ask you which software do you use ?

regards
David

I use Steinberg's Nuendo, it is a multi-track sequencer rather than a 1 track audio editor like Sound Forge (but I don't think you need multiple tracks)

I use wavelab as an alternative to Sound Forge, but Sound Forge is very popular and a great piece of software.