It may just be a matter of brace height and your big bow begging for a heavy arrow.
I own a Pittsley Predator, and it weighs 73 lbs at my 29 1/2" draw. Predators are very fast bows, and dead in the hand...BUT I have heard complaints about them being noisy.
I use a Delta type bowquiver that is always on my bow, Catwhiskers, padded limb tips, and Bow Hush wool on the string tips...AND a 750 grain arrow. My bow is VERY quiet. (except if my brace height is low)
(I found the String Leeches work better than ANY string silencer I have ever used, BUT, when I try them, the string literally cuts them in half with just a few shots.)
Providing your bow/arrow combo is tuned, the noise is caused from the string leaving your fingers, contact between string and limb tips, and WASTED energy. Harness that energy. Do NOT be afraid of a HEAVY arrow.
Seventy plus pounds and arrows in the 750-850 grain range are a hunters best friends...providing the weight does not affect accuracy.
What brand bow are we talking about?