As far as why the engine is so loud, I think it's really a combination of several factors: the higher revs is absolutely a factor, since it's just cramming more and more noisy power strokes into a smaller and smaller period of time. Also, the use of lighter weight materials throughout to counteract the vibrational forces is likely making things a bit louder as well, since thinner, lighter parts are probably less effective at deadening sound than a heavier, denser material would be.


And I'm sure there's some shrieking of the driver as he or she realizes this big V8 is revving up like a sportbike engine or something. That can get loud, too.