Why do AMERICANS talk so LOUD in public while in foreign countries?

We know that Americans read our blogg and thats why we write this in english.
Well, I (Tom) try my best :-)

No one of us have benn in US so we don't know how loud you are talking there.
But can you please tell us why americans "always" have to speak so loud when you
are abroad. Last year we had to listen to loudspeaking americans in Iceland, Prague,
Mexico and a lot of places in Norway.
You can hear an american five blocks away...or if you are sitting in a bar enjoying a
bottle of red wine with your love looking into your eyes through the candlelights...
its quiet in the room...all you hear is a little bit of cozy pianomusic from the speaker
a few meters away...it is a magic moment....UNTIL an american enters the room.