You find that with a large volume of people, comes the loudness of noise. They talk louder because they can't hear over other people who are yelling or talking loud. Being at a concert you encounter this with all the different equipment the musicians have around them. I have seen some exquisite Amplifiers which can burst your eardrums if you are standing next to them when they are being used. To shop for the type you need, click on the link in this post.