Fellow speaker,
If using a clip-on, lavalliere microphone, clip the microphone near the center of the chest. If you are a man wearing a dress shirt, this is just below the second button on the shirt. Attach the transmitter to the belt or place it in the back. If the speaker controls the microphone, place the transmitter on the side opposite their "handed-ness". For example, if a speaker is left-handed, place the transmitter on the right side. This will prevent the speaker from accidentally bumping into the transmitter during their speech.
Mic-ly,
Tim
