A plasma arc loudspeaker or plasma-dynamic loudspeaker is a loudspeaker that creates sound by varying corona pressure of an electric arc. It is an evolution of William Duddell's "singing arc" of 1900 and modern research into spacecraft propulsion in the form of the ion thruster.
It is claimed to be an advance on traditional loudspeaker designs because the driver has very little mass, and so low inertia, reducing distortion. It also has a frequency response far exceeding physical speaker cones, estimated as 50 Hz to 250 kHz.
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