Firing any gun in an enclosed space is going to be loud... But when it comes between your life and exposing your ears to a few loud blast of gunfire... Your ears take a distant decond to your life.
I do not use ear protection when I shoot .22 or .17 HMR out of a rifle. I do use ear plugs when I shoot my .17 HMR revolver. Its a good policy for whatever you are shooting.
I wear ear plugs when shooting handguns. Once you damage your hearing dont expect it to get better.
If you feel like dealing with the paperwork and expenses, a suppressor knocks down the noise a lot.