Editing Loudspeaker (section)

===Electrical characteristics of dynamic loudspeakers===
{{Main|Electrical characteristics of dynamic loudspeakers}}

To make sound, a loudspeaker is driven by modulated electric current (produced by an amplifier) that passes through a ''speaker coil''  which then (through [[Electrical inductance|inductance]]) creates a magnetic field around the coil. The electric current variations that pass through the speaker are thus converted to a varying magnetic field, whose interaction with the driver's magnetic field moves the speaker diaphragm, which thus forces the driver to produce air motion that is similar to the original signal from the amplifier.

The load that a driver presents to an amplifier consists of a complex [[electrical impedance]]—a combination of resistance and both [[Capacitance|capacitive]] and [[Inductance|inductive]] [[Electrical reactance|reactance]], which combines properties of the driver, its mechanical motion, the effects of crossover components (if any are in the signal path between amplifier and driver), and the effects of air loading on the driver as modified by the enclosure and its environment. Most amplifiers' output specifications are given at a specific power into an ideal [[resistive]] load; however, a loudspeaker does not have a constant impedance across its frequency range. Instead, the voice coil is inductive, the driver has mechanical resonances, the enclosure changes the driver's electrical and mechanical characteristics, and a passive crossover between the drivers and the amplifier contributes its own variations. The result is a load impedance that varies widely with frequency, and usually a varying phase relationship between voltage and current as well, also changing with frequency. Some amplifiers can cope with the variation better than others can.

Electrical models of loudspeakers are available that address these effects in detail.<ref>{{cite journal
  |title=Application of electric circuit analogies to loudspeaker design problems
  |author=Locanthi, Bart N
  |journal=IRE Trans. Audio
  |volume=6
  |pages=15
  |year=1952
  |url=https://www.aikenamps.com/images/Documents/speaker.pdf }}</ref>