The Loud Worshipper
Question: There is a pious member of the synagogue in which I pray who is in the habit of saying the silent Amida prayer in a loud voice which disturbs me and others who are trying to concentrate on our prayers. Must we tolerate his effort for greater concentration at the expense of our own? What is the right thing to do?
Answer: Although the Shulchan Aruch (Orach Chaim 101:2) rules that if one is unable to concentrate on his prayers while saying them silently it is permissible for him to raise his voice, this is limited to doing so in the privacy of his home. To pray loudly when praying together with others is forbidden because it prevents them from concentrating.
The issue then is not whether that member is acting properly but rather how to solve the problem he creates, to the satisfaction of all.
The solution suggested by one of the halachic authorities (Prisha on the Tur) of directing that member to pray in his home is rejected by a later authority (Pri Megadim), because it may set a dangerous precedent for others to avoid praying in the synagogue despite their ability to do so. Only if that loud worshipper is respected as a truly outstanding Jewish leader, whose every action is directed towards serving G-d, is it proper for taking this option of private prayer for the purpose of greater concentration.
Keep in mind that the worshipper to whom you refer may be ignorant of the fact that he is actually disturbing you, or of the halachic ruling that forbids him to do so. Your only recourse then is to gently inform him that he is indeed disturbing you, and to show him the halachic ruling regarding his behavior. A Jew who prays aloud with the intention of better serving G-d will most likely react in a positive manner and you will have succeeded in restoring silence while also preserving the peace.