I'm a Brit living in the states and I agree with Jeff G. Brits are much louder than Americans :-)
My b/f lives in Northern Ireland and, although his family may well be the exception, his house is one big yell fest. I don't mean they yell at each other - they just yell to each other. One person will scream the other person's name over and over until they finally answer by yelling "WHAT??!". I come from an extremely quiet home, so I've never really gotten used to it.