The Lapel Microphone

Abstract

AT public meetings and at lectures, the microphone and loud speaker is often a great boon to both the speaker, who speaks practically in his natural voice, and to the audience, who hear him clearly. There are some, however, who forget that they are addressing a stationary microphone and move about freely, with the result that sometimes they can scarcely be heard. To get over this difficulty, the Bell Telephone Company has invented the lapel microphone, a description of which is given in its Record for January. The microphone is only about an inch in diameter and weighs one and one-half ounces. A thirty-foot length of flexible cord provides the connexion to the amplifier of the public address system. The diaphragm is made of thin aluminium in the shape of a cone of sufficient stiffness to cause it to vibrate as a unit throughout the required frequency range. A rubber covering for the microphone eliminates the disturbing noise which would otherwise result from rubbing against the speaker's clothing, or would be picked up through the clip which is provided for attaching it to the clothing. The best place to attach the clip is to the lapel of the speaker's coat. This device has been used very successfully in large auditoriums in America. It should prove useful to speakers who depend on gestures for effective delivery or who need to turn to explain lantern slides or use a blackboard.