What's the meaning

of put faces to the noise here?

"Of course the first thing I did was talk to them. I didn't go out of my way to have a conversation just about the noise (the noise the kids makes on the floor above his apartment) but I waited a couple weeks until the first time we bumped into each other outside, and then after three minutes of small talk I nudged the conversation in that direction. And this helped a lot, even if only psychologically: just knowing that they weren't total clueless a-holes and being able to put faces to the noise really defused much of the situation."

Thanks a million!