FZ1 1000 exhaust without insulator?

Let me see if I got it, is insulator supposed to be some fibers inside the muffler chamber? this fibers are supposed to reduce noise. I got my bike with some kind of improvised muffler, which is just a horn without insulator, so two things happen with that, too much noise, it sounds very aggressive and loud, but I think that not so cool because I think that muffler make a more low frequency sound, which sounds amazing, I think that it makes the same effect as a subwoofer box, bigger the box = louder and deeper frequency?

The guy who sold me the bike, also gave me a two brothers exhaust, which is pretty big, not those compact form, I want to eventually install it on my bike, but without a type of insulator, so it will be louder? (not as much as now) but keeping a low frequency? I imagine that to be awesome. Thanks.