How Does A Megaphone Work?

If you are interested in sports, you must have seen cheerleaders holding massive cone-shaped objects while shouting out cheers in a game. You must have seen a similar thing being held by the police inaction movies when they want to communicate to a big crowd. These cone-shaped devices are known as bullhorns or megaphones. They help in speaking to crowds or vast groups of people by amplifying the speaker’s voice. It works similar to your cupped hands when you call out for somebody. How does it happen? Let’s find out.

The secret of the megaphone lies in its conical shape. The shape helps it in amplifying the voice for several reasons. Firstly, the voice gets directed to the target because of this shape. When we speak, the sound emanates from our mouth in every direction at once. Just a part of our output moves in the direction of our intended target. The function of a megaphone is similar to that of a funnel. It channelizes the sound we make and then focuses it towards the target. It is how less sound gets scattered in other directions. Apart from directing our sounds towards the target, a megaphone also aids in increasing the overall volume output.

Sound waves work uniquely, and this results in such an effect. When there is a sudden movement in the sound waves from narrow regions to vast open space, some sound waves are reflected towards the source. It happens when we speak. These sound waves move from the narrow space of our mouths immediately to encounter the expanses of open spaces. It causes some of the waves to reflect the mouth. It reduces our speech volumes effectively. However, while speaking in a megaphone, the sound waves leave your mouth but don’t encounter the vast open spaces immediately. Instead, the waves move through the length of the megaphone’s conical shape, which slowly becomes wider until the waves move out from the end. In this way, when the sound waves move across the megaphone, lesser waves bounce back and, hence, increase the voice volume.

Electric megaphones are handheld public address systems or electronic devices that amplify the human voice or any other sound like a regular acoustic megaphone, but the former uses electric power. They consist of a microphone for converting sound waves into electrical audio signals. They also come with an amplifier for increasing the audio signal’s power. A battery is used for powering the amplifier. The loudspeaker in an electronic megaphone converts the audio signal into sound waves again. Even though an electric megaphone is slightly bulkier than an acoustic megaphone, it can amplify the sound to a greater level, to more than 90 dB.

In most applications, acoustic megaphones have been replaced by electronic ones. They are usually used for addressing congregations of masses whenever there is an unavailability of public address systems, at street demonstrations, political rallies, movie sets, outdoor sporting events, and so on. Even though electronic public address systems have been on the scene since the early 1920s, during the development of vacuum tube amplifiers, the heavyweight of the vacuum tube versions makes them too hard to carry. It was in 1947 when the development of microelectronics took place after the invention of transistors. This led to the making of practical portable electronic megaphones. EM-202, the first transistorized megaphone of the world, was developed by TOA Corporation in 1954.

The shape of a microphone has a direct impact on the range of projection. Narrower horns have to concentrate the sound more sharply than the wide horns. This is for compensating for the low power. Handheld megaphones are usually shaped like the old acoustic megaphones, with a horn speaker at one end and a microphone at the other. It has a pistol grip on one side and a trigger switch for turning it on. While using the megaphone, it is held close to the mouth while pressing the trigger when speaking.

The bigger versions can be hung on your shoulder with a strap and comprise a handheld microphone on its cord for speaking into. This way, users can communicate to the crowd without letting the device obscure the faces. These days, there are a lot of types of contemporary electronic megaphones that you can buy. They come with a huge range of price, power, weight, shoulder straps, and even alarms for catering to the user’s choice. (See, Why do we hate to hear your own voice?)

For effectively amplifying your voice, your megaphone needs to be at least of the size of the wavelength of that sound it is intensifying. As human voices consist of wavelengths that move to numerous feet, the best megaphones are generally made as cones that are multiple feet long. You can use cheerleaders using them. Bullhorns, on the other hand, do not require to be very long. It is shaped into a much smaller cone. However, bullhorns can also be excellent amplifiers of your voice, all thanks to the speaker and amplifier, which electronically amplify the voice.