i have been thinking how to create realistic sound for a car. The main sound is the engine, then all kind of wind, road and suspension sounds.
Are there any open source projects for the engine sound simulation? Simply pitching up the sample does not sound too great. The ideal would be to something that allows me to pick type of the engine (i.e. inline-4 vs v-8), add extras like turbo/supercharger whine and finally set the load and rpm. Something like http://www.sonory.org/examples.html
The kind of one used in EA sports iphone games and firemints real racing games.
When sampling pitched instruments you need a variety of samples, called multisampling. So you'll have a sample for say 600RPM, one for 1200RPM, another for 2400RPM, and so on. It is best to provide samples for exponential increments (which is how pitch is perceived).
As well as providing multisamples, you will also want to provide samples at different velocities (sometimes termed as hyper sampling), such as when you are 2 feet, 20 feet and 200 feet away. There is a difference in texture due to proximity and the way that sound travels.
Also on top of that you will want to cross fade between zones so that transitions are smooth, as well as providing mild modulations such as EQ boosts, cuts, pass filter sweeps and so on.
You can also save yourself a lot of time by asking synthesis experts on music forums such as Propellerheads or KVR. They can inform you on what synthesis methods produce a convincing engine sound, and if they can do it through synthesis, you will have a much more authentic and interactive engine sound.