guys - don't compare modern planes to the old bombers and fighters in noise levels.Modern planes are regulated how much nouse they can generate and use special materials to achieve that - things they didn't care about in the past. If you ever been to a flight show you know what I am saying...
there are simply too many factors (altitude, speed, number of engines, etc) to make an accurate model and I think the stock is a good compromise all around (I am not an expert by no means, but the visibility is more concerning than the noise)