I haven't been to a wedding in a while, years it seems. I remember at the receptions, sitting next to my wife with 6 other people around a table. My wife would engage in conversation with a lady sitting next to her but in doing so, she'd turn toward her, away from me. I could then only hear a sparse word and it was annoying. Note my wife was sitting right next to me but I could not make out a full sentence on more than one occasion and she wasn't deliberately trying to be private. Her voice volume was normal.
I bring this up to illustrate points about sound. Wedding receptions (or sports games) are loud at times, like while the music is going, while the away team is shooting free throws in a basketball game or while the away team is serving in a volleyball team. It would be difficult to hear an individual unless they were somewhat close and facing you. As everyone is facing the sports teams, the teams are not obstructed in hearing by direction. However, audience members behind someone screaming will have less capacity to hear and more opportunity for sound interference to play a role.