Is it possible that the game is outputting audio through audio channels you don't have?
For instance, if yous et the game's audio dynamic range to home theater while you only have a stereo setup. This would cause the game to output a 5.1 surround signal through stereo speakers, which means some audio, more specifically everything going through the central and real speakers, can't be heard.
Since your character walks in the center of the screen, your armor sounds might come through the central speaker. Party banter is also output through the central speaker. I want to know if you have subtitles disabled, because if the game outputs in surround and subtitles are disabled, you wouldn't know if there were party banter if you only have a stereo setup. In that case you'd have to set dynamic range to headphones.
This was also a hypothetical cause of the "banter bug" as proposed by BioWare, who after reviewing several save files by affected players found no actual party banter bug. I think they still don't believe it exists.