Engine And Exhaust sound smoothing out at higher rmps

Why does the engine and exhaust sound smooth out after a certain amount of rpms? In my case it smooths out around 830 rpms. I am using the stock Gavril 4.5L V8 engine with only the Engin Audio Debug Tool. I have screenshot two pictures to show you. Is there a way to keep the engine and exhaust note from smoothing out as I accelerate and is it possible to change at what rpms the engine and exhaust note smooths out?

 

The Note of an engine naturally smoothes out as the rpm increases because the human hearing apparatus can no longer distinguish between different cylinders firing, that's the reason why the engine Note of, for example a v10 f1 car at Max rpm is just one singular high pitched scream

 

when I had the d series exhaust configured the way it was in that it almost sounded like the idle wasn't sounding like it wasn't part of the rest of the engin/exhaust. to get a better idea of what I am talking about spawn up the d series remove the muffler and open the engine audio debug tool and set it to the same presets as in the picture above and slowly (with the r trigger or pedal) accelerate to around 830 rpms and then you will notice a change in the sound one you start getting above that. And also it may be the lack of a proper cam profile simulation

 

Cam profiles aren't simulated at all

 

Yeah bad choice of words! lol! I meant the lack of having cam profile in the game.