So more interesting results, all with these settings: Listening Position 62, Party Effects-Limited, Others Effects-None, Object Quantity-Low.
I got zero audio stuttering at all in the first three floors of the new raid. Then in the fourth floor, I got the normal amount; changing Listening Position to 100 reduced its frequency greatly but did not eliminate it 100%, just like what happens in other duties that have stuttering. The stuttering in the fourth floor didn't seem to coincide with any special skills or events either. Hell, it happened even while the boss was only casting a simple raidwide attack with no special floor effects active or anything. Perhaps healers and others were casting several reduction abilities that I couldn't see because of Limited Party Effects, although you can still HEAR those effects, so I'm not sure if that setting is really doing anything, but it felt like it might have had an effect in Alliance Raids.
I really am at a loss here. It's like there's almost no consistency. It's crazy that it varies so much not only between people but for a single person as well.