What plasma loudspeakers are

What they are

The most exotic speaker design is undoubtedly the ionic or plasma arc loudspeaker, using electrical plasma as a driver, once commercially sold as the Ionovac. Since plasma has minimal mass, but is charged and therefore can be manipulated by an electric field, the result is a very linear output at frequencies far higher than the audible range.

A Ionic speaker is a loudspeaker that creates sound by varying air pressure through a corona discharge or 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.