So back in April I was able to pick up a very nice, used Fox Triple Crown that is 68" and 46#@30". Set the brace height to 7 1/2" per Ron King's Fox Archery website -"Triple Crown recommended brace height should be 71/2" to 81/4." Left the nock where it was on the string so I could get a dozen arrows in right after the bow was delivered. By the third or fourth arrow I was expecting the local police to show up and inform me I was violating the town noise ordinances. Tried several different arrows, nock points, and brace heights in the range Ron recommends without effect. Not only was it noisy, but I was lucky to get 8"-10" groups at 15 yards. Recognizing the bow was going to be a "challenge", I hung it on the rack where it has stayed the past 4 months. Finally took it back out today at lunch to shoot one last time before I put it up for sale. Cranked the brace height up to 8" and tried 4 different sets of arrows and 2 different nock point locations but it sill sounded like a 5.56 round from an AR every time I shot it. Feeling frustrated, I put another 15 turns on the string and shot it again with both carbon and wood arrows. Noise level was a very acceptable "thud" and accuracy at 15 yards was consistantly like that in the picture with several different sets of arrows. Out of curiosity I had to put a ruler on the brace height and was amazed when it measured every bit of 9".
So am still trying to get my head around what was causing the noise problem. Is it possble that the bow was tillered for 3-under and me shooting it split finger was creating the problem? Could it have been the fact that the bow was built for a 30" draw and my pitiful 27" draw was causing the problem? Did I not move the nock point enough when I was messing with it and the very high brace height changed it enough to silence the bow? Tried long arrows, short arrows, heavy weight arrows, wood, carbon, and bamboo, but nothing seemed to help with the noise. Curious about your thoughts on what I was missing.

Is the string dacron, or equivalent, and less than 15 strands? If the bow will handle a non-stretch string, try one with a brace height of 7.5 to 8.5" Again, you can try changing the silencers or putting some on, Wool yarn works. Put them at different spacing, like 6" and other 8" from the contact with the bow. Try heavier arrows, Are the arrows hitting the shelf, sprinkle some Talcum on the shelf and window.
Bob...gonna guess if it was out of tiller enough to cause noise it would have thumped in your hand. I have a three piece that likes 8+ inches of brace. Never took it to 9" though. Also... i had a bow that was worked poorly for my particular hand / wrist and i would slap the hell outta my arm guard, making noise. A long sleeve shirt made it worse ( noise). Increasing brace kept it away from my arm guard.
Every bow is different, not all react the same way to any given tuning setup. Incorrect nock point height is a common noise-maker (even if arrow flight is ok) and so is slight limb twist, the string itself (poor construction), and don't forget issues caused by a poor release. Maybe some experimentation could help.
When you increase BH you increase the poundage. My guess without seeing you shoot and the info you've given that the arrows were too stiff. A very common problem.
Bowmania
Bob, The 9” brace height is too high for that bow. I’ve shot bows split that were even tillered without any loud noise. I had a well known bowyer tell me once that he builds all of his bows even tiller so, I doubt that’s the cause if the sound is as loud as you’re saying it is. You should give Ron a call.
those bows tend to like a little heel pressure (firm grip)
they are very nice and accurate bows