I have a player who has an issue with loud noises, especially the persistent loud noises of raised voices (less so occasional shouting). Loud voices have an energy to them which in some games is not only logical, but which could make it very difficult for people to keep it to a reasonably quiet level. Plus a few of our louder players have their own issues (i.e. ADHD) which can make it difficult for them to moderate their tones especially when the situation calls for loudness. Attempting to do so would be incredibly draining to them, presuming they could manage it. Now while there are some games that reward and encourage quiet and respectful tones (stealth games, some political games) others include loud volumes as a matter of course. And simply telling groups of people to be more quiet lasts for about 5 minutes before the volume steadily rises. How do we find the balance between the two sets of needs? What kind of environment might encourage people to keep their voices down — or at least not be persistently loud?
This is definitely a tricky situation to be in and one I think a lot of conscientious organisers have come across.
Firstly I think it’s fair to say that any event with large numbers of people, unless it is specifically something which should be quiet like a stealth mission, is likely to get noisy. Most people with noise sensitivity whether due to neurodivergence, mental health or hearing impairment are going to be aware of this and understand that it is something they have to consider. The first step is letting players know if crowd noise is going to be an issue and that can be as simple as stating the number of players or describing the basic game play – 100 people in a scout hall is far noisier than 100 people spread out camping in field for instance. Already you are helping players prepare.
This stage is usually where you would tell players if it is an overnight event if sleeping is OOC or IC and what times are time in if it is not 24hr. If this is the case you can also include details of when players are expected to keep the volume lower for people to sleep, if appropriate for your game.
After that you can start thinking about specific things you can put in place that may be helpful. Think if the game and venue lends itself to having different In Character areas, preferably in different rooms. It is often possible to make some of these IC quiet areas in an IC manner, for instance by creating an area effect or aura of calm on a particular room; set dressing it as a temple or other quiet place; creating a roleplay effect that rewards quiet and so on.
This means that there is an In Character place that people can go to if they can’t deal with loud crowd noise but want to continue roleplaying. It also means that it is easier to ask people to pipe down either OOC or IC and have that respected (though ideally people should respect those wishes anyway as you note it can be difficult if it’s a large group).
The alternative or addition to this is providing an OOC quiet space that people can go too if they need a moment to calm, refocus or manage their own access needs. OOC quiet rooms can help a lot of people and I generally encourage having them available. The downside to an OOC quiet room is of course that the player has to drop OOC but that is often preferential to not being able to get away from the loud noise at all.
If you are running an overnight game it is worth making sure that OOC and IC quiet rooms are near the OOC sleeping quarters, as that also means that any late night noise roleplay should be going on further away from people who need to sleep.
Know where are likely to become busy and noisy areas and keep an eye on where is quieter during Time In. For instance the dining room is likely to get very noisy at meal times, so offer the option of eating in a different room for players who need it. It also means that if you notice a player in distress you can help guide them to a more suitable area.
Then there are rules options you can think about. Many games make use of some sort of sign or token to signify that a person is acting OOC in an IC area. How these work can vary dramatically but they are very good for people who need to remove themselves from an OOC difficult situation (such as anxiety inducing noise) with the minimum of fuss. Pictured is a “take a break” tag that was used at a recent Empire LRP player event. People with access needs could use it in different ways to suit their needs but one way it could be used was to say “I need to step out for a bit” without having to actually explain in detail to other people. Players also had the option of having an individual phrase written which might include something like “I need a quiet area”. We were lucky to have these made in wood for our game but there is no reason they couldn’t be printed cards or similar.
[note: for players who struggle to communicate verbally in times of need you may with to consider communication tags as shown in this post.]
Other mechanisms may include a hand symbol, for instance a hand on head, or verbal call such as “Break” which allows the person to break from a scene for OOC reasons and relocate as necessary. Again this isn’t just for noise issues but it is one manner this can be used.
Other than that you can of course look at ways of folding quiet in to your plot. As you mentioned in your initial question, some games with stealth missions are inherently more quiet and there may be other things you can do to encourage lower voices from waking monsters to sound eating spells.
Though your question was mainly focused on neurodivergence and mental health reasons for noise aversion, crowd noise can also be tough on some people with hearing impairments. In those cases you may need to talk to the individual to find out what helps and hinders them and look in to things like hearing loop systems the venue may have or other aides that may help the player.