A megaphone amplifies sound by increasing the sound pressure level of the voice or sound source. It does this by directing and concentrating the sound waves into a narrow beam, effectively increasing the acoustic energy in a specific direction.
The basic design of a megaphone consists of a cone-shaped horn that is open at one end and narrows to a smaller opening at the other end. When sound is produced at the small end of the cone, the shape of the horn acts as a kind of acoustic transformer, directing the sound waves and increasing their amplitude, or the amount of energy they carry. The cone-shaped horn also helps to focus the sound waves into a narrow beam, further increasing the sound pressure level.
In a megaphone, the sound source is typically the user’s mouth, and the amplified sound is produced by the combination of the user’s voice and the acoustic properties of the megaphone itself. The megaphone increases the loudness of the sound without altering its quality or frequency content, making it an effective tool for amplifying speech and other sounds in a specific direction.