Megaphone

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Megaphone

A megaphone, speaking-trumpet, bullhorn or loud hailer is a portable, usually hand-held, funnel-shaped device whose application is to amplify a person’s voice towards a targeted direction. This is accomplished by channeling the sound through a funnel, which also serves to match the acoustic impedance

Acoustic impedance

The acoustic impedance Z is a frequency f dependent parameter and is very useful, for example, for describing the behaviour of musical wind instruments....
of the voice cords to the air.

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Acoustic impedance

The acoustic impedance Z is a frequency f dependent parameter and is very useful, for example, for describing the behaviour of musical wind instruments....
of the voice cords to the air. The natural human voice

Human voice

The human voice consists of sound Voice production by a human being using the vocal folds for Speech communication, singing, Laughter, crying, screaming, etc....
tends to spread evenly in all directions, whereas when it is sent through a megaphone, the sound is concentrated in a given direction and the coupling of its energy to the air optimised. The trade-off is that if a listener is to the side, it is more difficult to hear what is being said. An electronic megaphone amplifies sound to a higher decibel

Decibel

The decibel is a logarithmic units of measurement that expresses the magnitude of a physical quantity relative to a specified or implied reference level....
level. It consists of a microphone

Microphone

A microphone, sometimes referred to as a mike or?more recently?mic, is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal....
, an amplifier

Amplifier

Generally, an amplifier or simply amp, is any machine that changes, usually increases, the amplitude of a Signal . The "signal" is usually voltage or current....
and a loudspeaker

Loudspeaker

A loudspeaker, speaker, or speaker system is an electroacoustical transducer that converts an electricity signal processing to sound....
.

Common uses for megaphones are at sporting events, political functions and generally when one needs to address congregations of people in open spaces. It was invented by Athanasius Kircher

Athanasius Kircher

Athanasius Kircher was a 17th century Germany Society of Jesus scholar who published around 40 works, most notably in the fields of Orientalism, geology, and medicine....
during the 1600s.

Megaphone

See also