OK, I just loaded alternate chambers of my S&W 63, functionally identical to your 617, with Colibri and Super Colibri and fired them without hearing protection on my little back porch range. Both produce no discomfort outdoors, though this is the first time I have fired them without hearing protection from a handgun. I have not and will not shoot them indoors without protection. The Colibri are quieter but not enough to matter to neighbors, wildlife, or livestock. I then loaded alternate CCI CB Short (CCI catalog #0026, 29 grain bullet, 727 fps from 18.50 inch barrel, same stats as the #0038 CB Long, and, BTW, not powderless) and Super Colibri. On a purely subjective basis the CCI CB are 2-4 times louder to my completely uncalibrated ears and I will not be firing any more without protection.
My best guess? If you shoot in a basement or a room without a common wall with a neighbor, the Colibri and Super Colibri will bring no complaints. Shoot either in a room with an exterior wall, especially one with windows, and someone on a sidewalk or in a neighboring yard will be aware of it.
Note well: even at close range, the Colibri and Super Colibri will bounce off plywood. Use a bullet trap that safely deals with that.