Loudspeakers

A loudspeaker is an electroacoustic transducer intended to radiate acoustic power into the air, the acoustical waveform being essentially equivalent to that of the electrical input. Electrodynamic, electromagnetic and electrostatic driving systems have been used for loudspeakers operating in air. However, during the past two decades the electrodynamic has overwhelmingly predominated in all applications for loudspeakers operating in air. The almost universal use of the direct-radiator dynamic loudspeaker in radio receivers, phonographs, magnetic-tape reproducers, television receivers, announce and intercommunicating systems is due to the simplicity of construction, small space requirements and the relatively uniform response-frequency characteristics. For small-scale applications the low efficiency of the direct-radiator loudspeaker is not a handicap. However, for large-scale high-power sound applications, the high-efficiency horn loudspeaker is particularly suitable because the amplifier requirements are reduced by an order of magnitude. For the future, the promising developments in loudspeakers appear to be in the field of motion control.