Why Do Megaphones Make Sound Louder?
Other People Are Reading
-
Sound Is Really Vibration of Air
-
Sound is no more than vibrations of air that can be decoded by the human auditory system. When an individual speaks, air flows from the lungs, across the vocal chords, and out through the mouth; movements of the tongue and lips help articulate specific sounds. As the air passes over the vocal chords and the tongue, the vibrations of these body parts generate the individual's voice. The vibrations travel through the air until they are received by another person or a group of people. When the vibrations arrive at the listener, they cause the sensitive membrane of the listener's ear to vibrate. Sensitive nerves within the ear carry these vibrations to the brain where they are decoded into sound.
Sounds Tend to Disperse
-
When an individual speaks, or even yells, the air vibrations exiting the mouth scatter in a broad range of directions. Under normal circumstances, this scattering of air vibration is helpful because it allows listeners to hear the speaker no matter where they are in proximity to the individual's mouth. In noisy environments or over great distances, though, the scattering of sound causes the speaker's voice to rapidly dissipate; likewise, the concentration of people in crowded venues allows the air vibrations to be absorbed by bodies, clothing, and personal effects like handbags. For this reason, a speaker on one side of a crowded auditorium is unlikely to be heard very well by someone on the other side, as the vibrations of the speaker's voice are both scattered and quickly absorbed by other individuals closer to the source of the sound.
-
Megaphone Concentrates Sound
-
When a speaker speaks into a megaphone, however, the conical shape of the device captures the air vibrations and prevents them from scattering. As the vibrations travel through the megaphone, they are protected from interference by other sound sources (such as other people talking or yelling). The sounds exit the megaphone as a tightly packed, concentrated collection of air vibrations that are able to be travel greater distances without being dispersed or absorbed by nearby items. While a listener who is standing or sitting beside someone using a megaphone may not hear the speaker as clearly as if he were not using the device, someone in the path of the megaphone's projection, that is, someone who receives the concentrated collection of air vibrations, interprets the sound as much louder than if the megaphone were not used.
Megaphones May Be High or Low Tech
-
The traditional image of a megaphone is a cone-shaped plastic device with or without a handle. While this image represents the classic megaphone, other types of megaphones are also readily available. Some high-tech megaphones allow a user to speak into a microphone; the system picks up the user's voice as sound waves, converts them to electronic signals, and plays them through a powerful, amplified speaker; the speaker then uses the acoustic amplification of traditional megaphones to further boost the sound before sending the vibrations out to an audience. On the opposite end of the spectrum, a decidedly low-tech approach to voice amplification is to simply cup an individual's hands around the mouth when speaking. This process catches the air vibrations as they exit the speaker's mouth, preventing them from instantly scattering. While the cupping of hands may not give as much of a boost to a voice as a traditional megaphone, it is a simple and free way to quickly project a speaker's voice when needed.
-
