Well, putting my personal opinion on the back burner about the situation, and answering the question I would have to say that, in part, the sound is being muffled because you are recirculating the bov (hose that goes back to the intake pipe). This is a good thing and you should not change it, but if you took that hose off that would probably amplify the sound too.

Before I got my AEM EMS I had that bov and it was recirculated. It was barely audible. Now I'm using a speed density setup so with no MAF it is VTA. Now it's loud as all hell, so it definately does make a difference.