I am suffering from a medical condition called hyperacusis, which makes normal levels of noise painful (and potentially damaging) for me. I have found ways to cope with this condition in my daily life, mostly by avoiding noisy situations and events, but sometimes even people's voices can be very painful, in particular if I am having a long conversation with someone in a small room or office, which my occupation frequently requires, and if my interlocutor has a high-pitched voice and comes from a culture where speaking loudly and confidently is encouraged.
I tried explaining my problem explicitly, and insisting that the problem is on my side and that I am not blaming the other person, but I noticed two types of undesired reactions to my request. First, some people seem to get offended by my explanation, which insinuates that the volume of their voice might be inappropriate. Second, some people do not take my request very seriously and seem to think that I am exaggerating, or that my problems are psychological (I am speculating here, this is just my impression). Anyway, this initial exchange does not put the conversation on the right track. Oftentimes, even when people make an effort initially, they quickly (and naturally) go back to their habits, and I find it very difficult and embarrassing to give them constant reminders.
I tried other strategies (lowering my own voice in the hope that my interlocutor will unconsciously imitate me, pretending that we need to speak softly to avoid bothering my colleagues in other offices), with very limited success.
How can I politely ask people to tone down without offending them, and without sounding too weird?
Many thanks to all for the answers and comments. I would like to clarify two things:
I don't need to bring the topic with all my interlocutors. I would say that only 20% of them speak at a volume which is painful/dangerous for me. Of course, I don't mention to these people that they are "special", but I still have the impression that my request offends a large fraction of them, perhaps because they have already received some comments about their voice from other people.
the specialists told me to avoid using earplugs when I speak (as they amplify your voice, which can even damage the inner ear in the long term due to bone conduction). And I think that plugging them and removing them frequently when I or my interlocutor starts to speak is not exactly helping me on the "akwardness" scale :)