Exhaust sound on deceleration

Hi all,

I was wondering if anyone (1) noticed the same and (2) know if its a bug in my sound driver or a normal exhaust note.

On some of my S2 cars, when I am slowing down and dropping gears, instead of the normal pop and rumble I hear in most of my cars, I hear a sound almost exactly like the spaceships on the cartoon The Jetsons’.

Thanks all!