We went to the one in London recently with DS (5) and DD (2). DD is very sensitive (scared of TV programmes etc), so we asked to be sat away from the main noise making animals. We were sat near to some butterflies and a big tank of fish. We could then go and check out the big animals when she was feeling a bit braver.
The place we were sat was less atmospheric than by the main animals, but it worked well for us.
Perhaps you could do the same if you are concerned?