RE: Wow, 450plus is loud
Lots of things will make a difference, and some materials are louder on some bows. From what I've seen (heard), a material that's loudest on one bow may be the quietest on another. I shoot Dynaflight '97 on my personal bows, and get comments all the time on how quiet it is.
The right silencer material will make a difference. I love the look of fur silencers, but in my experience rubber "cat whiskers" work the best. As missedagain pointed out, where they are placed can make a big difference also. I've tinkered with a few short bows, and when the silencers were moved 1" it made a big difference.
Another thing we often don't consider is the pitch--a higher pitch will often sound louder to our ears.
Hope this helps.
Chad