Not directly related, just something I read recently:
Quote:The loudest component of the noise of passenger cars traveling over 40 km/h is car tyre noise, and nobody knows why. (Knowing why could be lucrative with 100 million car tyres being sold annually.) Air pumping noise generation mechanisms are an active area of research, and might include noise generated by partial singularities present due to the opening and closing of cavities as the tyre flexes.
Car engine sound synthesis is possible, but most certainly not trivial, one would need some sample code, or at least algorithm documentation I think.
One example I've seen was a single cylinder combustion signal with a simple engine, chassis mechanical frequency response, plus a bandpass for the muffler. Complicated crap. Too bad there is no open source code out there in this area, at least I haven't found any doing a quick online search.