First I wanted to thank those on this board that helped out with my first project. And now the results. After trying several of the suggested shroud configuration I have determined that using the pvc pipe \ scotch brite mod is the most quiet.
However it did not quiet down until I had taken several shoots. At that point it become noticeably more quiet.
I have 5 confirmed kills using JSB predators. The furthest a pigeon at 33 yards.