I have always been quiet, sometimes I will moan quite a bit during an intense orgasm, but try to keep it quiet.
We live in an apartment builiding and the walls are not sound proof at all.
The woman who used to live upstairs from us was a phone sex girl and had no problems with being loud. She used to talk to someone, but there was never anybody else in the room, we were told that she did not have a boyfriend. She would do this at least three times a day every day. There were times when I wanted to clap and cheer when she was finished.