You know that sound and you just hear it like "oh that's a wrx, that's a mustang, that's an Evo" etc. Okay, so how do manufacturers replicate that sound from year to year even when they redesign the engines? For example Mitsubishi put the new 4b11 motor in the Evo X and last year's Evo 9 had the 4G63 motor. The 4g63 was an iron block and the 4b11 is all aluminum yet these engines sound so similar. Same with the Porsche 911: over the years obviously they've changed motors and such yet that classic Porsche sound still carries over. SO what is it that makes an engine produce these unique sounds?