I've been around a lot of suppressed arms, and aside from one competition rifle that was specifically designed to be silent (and cost many thousands of dollars

I've been around a lot of suppressed arms, and aside from one competition rifle that was specifically designed to be silent (and cost many thousands of dollars to get that way), can't recall a single one in which ear protection wouldn't have been dramatically preferred for indoor shooting. Even for that one (subsonic, small rounds, suppressed, nitro piston), it would probably have been irritating to fire indoors. Edit: In hindsight, I suppose a suppressed, rimfire 22 would be pretty quiet.