Kris,
I took off the brush buttons on my Widow because they actually caused noise for me. I live in an area that gets cold during hunting season. As soon as the temperature dropped down near freezing, the brush buttons got hard as acorns. They smacked against the bow limbs and my bow sounded like a 22 rifle.
I also use a second set of beaver wraps way up next to the tip, where the string contacts the limb. I actually used only one wrap and cut it in half. I tied it so when the bow is strung but not flexed, about 1/2 inch of beaver fur is wedged between the string and limb. My thought is that on release, the tip flexes forward and the string strikes the limb below the contact point of the unflexed limb. It did help.
Another thing I've noticed with fast flight string. As they get used, they begin to make more noise. I think whats happening is that the string wax is slowly getting squeezed from between the stands as we shoot. The more we shoot the more wax gets displaced. The wax actually cushions the sound so the more we displace, the more noise she makes. I unstring my bow and wax the string, making sure I work wax in between the strands. This sometimes does the trick but after a while, a have to change strings. I did have one string that was load right off the bat. I had to throw it away.
Check your brace height. Usually you can make a big difference with just a small adjustment. My bow is load at 8&1/2, quiet at 8&5/8 and it starts getting load again at 8&3/4. There is a sweet spot and it takes some looking to find it. One trick that seems to work for me is lightly pluck the string and listen. Twist the string up or down a turn or two and lightly pluck it agian and listen again. You should hear the tone change when your getting close to the spot. Bare shaft tuning will nail down the spot.
Another BIG help is arrow weight. My Widow is load with any weight less than 10 grains per pound of draw weight. Example, 55lb draw requires a 550 grain arrow, minimum. The heavier the arrow, the more energy is transfered to the arrow on release. The noise we hear is actually energy being wasted. Try increasing your arrow weight and I'll bet your bow gets quieter.
Every bow is different and every archer has a little different form. I've shot bows that cracked like a gun for me. When the owner shot the same bow, it seemed quiet. Work at it and you'll smoth her out. Good Luck!