LFS sound engine is very challenging and interesting from an engineering point of view. It attempts to recreate the whole sound of a car from very simple sounds, like one explosion in one cylinder.
Nice, but it does not work. The sound of a car engine at 4000 RPM is not the sound of one cylinder explosion played 4*4000 times per second.
When you record a real car engine at 4000 RPM, and you look at the frequency analysis, you can see an incredible number of sounds at every frequency level mixed together.
Explosions in cylinders generate thousands of other noises because of transmission and addition of vibration in parts of the car. And these noises are not neglectable and reach the same level than the cylinder noise, and can completely change the nature of the engine noise at different RPM.
The only way for LFS sound system to produce something life-like would be to add hundreds, thousands of parameters...tiny metallic noise, muffled or not, dozens of options to decide how irregular and cyclical is the idle noise...etc.
ISI approach is in fact the same than in LFS, but try to use richer samples. They take several samples, adjust their frequency to RPM, and add them together. But instead of adding a dozen of small samples, they add 4 or 5 larger samples which already contain all these vibrations.
With CSR (Car Sound Remixer) addon for LFS, you can check yourself what becomes LFS sound with a ISI-like sound engine. The result is amazing. So much alive than default LFS sound. I found this addon today and it saved me, because I was upset with LFS sound after comparing with rFactor and Race 07. LFS diserves better.
Please try this addon, with the sound package in the thread:
http://www.lfsforum.net/showthread.php?t=12863
The best solution would be to use ISI approach, but with more samples to cover the entire RPM range of the car. 4 samples is not enough.
Concerning LFS state of development:
- they are 3, they go as fast as they can, and people ask for more.
- the only way to go faster is to hire someone else, but they have to pay him/her.
- people are ready to pay for more...no doubt about that.
- hiring someone may be a risk, but according to preceding points will certainly give an increasing success. Most companies hiring are not sure at all there will be a market for their product. LFS team has an almost garanteed development if they want.
So the problem is not a problem, it's a choice. They have chosen not to risk any further development of their team because the slow-pace is part of their business model and quality of life. But on the other side they risk to have more and more customers unsatisfied and finally to collapse. On long term, no growth is always more risky than growth.