Having suffered hearing loss and having titinitus (ringing in the ear) I can say the blowhards who say you hear NOTHING due to stress and this will protect you are wrong.

Prolonged exposure to sudden exposure can PERMANENTLY cause hearing loss.

Use LOWER Decibel ammunition which means lower velocity.

BIG and SLOW is better for indoors in my opinion or small slow and weak.

For urban encournters a 32 ACP might not be bad. Not too loud and not too penetrating, however it's not too lethal....