Why Do Megaphones Make Voices Sound Louder?
To understand how megaphones work, we first must understand how sound works. When someone makes a sound, it creates a sound wave that moves out in every direction from the point of origin. These waves disturb the air surrounding them, allowing the sound to be carried over a long distance. Under normal conditions, a soundwave moves at 1130 ft/sec (feet per second).
This is what is known as the speed of sound. A good visual analogy of how a soundwave works can be seen by dropping a pebble into a bucket of water. The waves that flow out from where the pebble was dropped work the same way soundwaves do. When they hit the end of the bucket, they are reflected back towards the point of origin. Those reflections represent echoes. An echo is a soundwave that bounces off an object and reflects back causing a repeat of the initial sound.
Now, had you chosen to drop the pebble into the middle of a pond or lake instead of a bucket, you would notice that the waves created by the pebble begin to weaken as they expand. Sound works the same way. The farther away you are from the source of the sound, the weaker the sound waves will be. Now that you have a general idea of how sound works, we can now look at how megaphones work.
If you have ever cupped your hands around your mouth to yell to someone a good distance away, you have made your hands into a rudimentary form of megaphone. A non-electronic cone-shaped megaphone works by taking the sound that comes out of your mouth and focusing it to a single direction. These types of megaphones are most often seen in the hands of cheerleaders at sporting events when they want to address the audience.
Another visual representation, similar to the pebble and bucket that you can use to see how a non-electronic megaphone works is to attach a multi-pattern spray nozzle to a garden hose. On a mist setting, the water goes in a wide spray, flying in just about every direction, much like how your voice would spread out without the megaphone. However, when the nozzle is adjusted to the jet setting, the majority of water is flowing in a much more focused direction.
The focused direction of the water on the jet setting is similar to how your voice is focused by the megaphone. You may still have to yell when you are using a non-electronic megaphone, but because it focuses your voice toward your intended recipients, you won’t have to yell as loudly as you would without one.
Next, is the electronic megaphone, also commonly referred to as a bullhorn. The bullhorn can be broken down into 4 basic parts. These parts are a microphone, an amplifier, a speaker and a power supply. When someone speaks into the microphone, it is electronically amplified by the internal amplifier. The level of amplification is dependent on the amount of power supplied to the megaphone.
From the amplifier, the sound travels to the speaker which directs the sound through the cone-shaped end of the bullhorn. This whole process takes such a brief amount of time that to us it seems instantaneous. Electronic megaphones have a far more effective range than their simple cone-shaped counterparts due to the electronic amplification. They also have the advantage of not requiring you to yell to project your voice further.