This is a little known trick made popular by comedian Robert Schimmel. When the audience gets loud, there’s a tendency to try to shout over them and feel that you’re going to win because you’ve got a mike and an amplification device. This doesn’t work unless you are by nature a very loud performer. Even then, you’re playing an extremely dangerous game. You better have some winning bits up your sleeve to succeed at the yelling game.
Instead of yelling, do what Schimmel does and get unbelievably quiet. When you start talking very quietly the audience will quiet down to hear what you have to say. It works, but for it to work, you have to commit to it. Keep doing it and the audience will eventually quiet down. They want to hear what you’re saying.
In a great pdf on how to give successful conferences (PDF), he gives tips for attendees:
I have attended keynotes with some of the country’s most wealthy millionaires and billionaires. And those were the most uninspiring and unrevealing speeches. You know why millionaires and billionaires become and stay millionaires and billionaires? Because they don’t reveal valuable information to hundreds or thousands of conference attendees.
The only exception I can think of is watching a MacWorld keynote with Steve Jobs who always delivers something valuable (usually a product launch) during his keynote. For everyone else, stay out in the hall and…
…Have a conversation The one hour you missed in the keynote room will be happily remedied by engaging in a conversation with all the other smart attendees who decided to wait in the hall. You’ll be surprised what stories and connections you can make with anyone who is attending a conference the two of you are both interested in. And if you still don’t think I’m right, when the keynote breaks ask someone walking out what they thought. Chances are they’ll just shrug and sigh in disappointment. And if by remote chance it happens to be fantastic, don’t worry, someone will write it up in a blog or trade publication. No one will write up that conversation you just had in the hall.