According to professional speaker Eric Edmeades, when you begin your speech, start with low energy and gradually through your speech build the energy to a crescendo. This is because there are three types of people in your audience: kinesthetic (low energy), auditory (medium energy), and visual (high energy). Starting with high energy annoys the kinesthetic people and can drive them out, while starting with low energy does not bother the auditory or visual people. The result is you will satisfy all three types of people in your audience.
Starting low,
Tim Wilson
Professional Speech Coach
Free speaking tips at: http://speakingquicktips.blogspot.com