A amplified speaker is a device that converts electrical energy waves into mechanical energy waves or audible sound. Sound is produced by the vibration of an object. This vibration creates a series of ripples or waves, like throwing a stone into a pond. A amplified speaker reproduces sound waves (or audio) at various frequencies. The frequency is the rate at which particles in the air vibrate. The human ear can hear sound from about 20 hertz (Hz) to 20,000 Hz or 20 hertz (kHz). Amplified speakers can be used in all types of communication and entertainment equipment, such as radio and television receivers, tape recorders, telephone answering machines. Baby monitor and stereo home entertainment system.
Since 1874, Ernst Siemens applied for a dynamic amplified speakers, its fundamentals have hardly changed. Siemens described his invention as a device for obtaining mechanical movement of an electric coil from the current flowing through it. The original intent of his invention was to move the telegraph arm. Two years later, Alexander Graham Bell applied the principles of the Siemens device to the telephone. Thomas Edison invented the now well known amplified speakers. It consists of a flexible diaphragm (cone) attached to the throat of the acoustic speaker.
Early amplified speakers used a variety of materials for their cones, such as thin metal sheets, leather and paper. Paper was (and still is) used in the construction of speaker cones because it was cheap and easily available.