What are the uses of plasma speakers, ionic loudspeakers and other massless devices when used to make sound? There are many applications outside of this field using related technology, such as ion drive engines, air purifiers, corona wind lift devices to name a few. But here are some possible sound related uses. Hi-fi Audiophile Listening As these devices can run hot, require high voltages and produce toxic gases it may be that they are never used as a general purpose loudspeaker. However, if you are willing to put up with these downsides and their mitigations then the promise that they produce sound with an inertialess driver becomes appealing to the listening goal of some audiophiles.
Tweeters Already the most common use of massless speakers, the plasma tweeter has been commercially produced for over 70 years, thanks mainly to the efforts of Siegfried Klein and the Ionophone. It is still a low volume niche product but produced and used today in high end loudspeaker systems such as Acapella and Lansche.
Full-range Speakers It seems the full-range speaker has been a harder path. Plasma has little volume to be able to drive the large amounts of air that bass requires. The use of a lot of plasmas or a large ionic transducer have so far only been theoretical or curiosities at best. One way the full range can be achieved is in headphones as there is less air volume to drive. This has been commercially exploited once with the Plasmasonic.
Ultrasonic transducers One aspect of the plasma or ionic transducer is its extended high frequency response range. This means it can have uses in areas that need very high frequency (up to MHz) ultrasonic sound production.
Noise Cancelling This may theoretically be a use for the corona wind or ionic loudspeaker where its lack of physical mass and no solid barrier can allow gas to pass through it while any unwanted acoustic disturbances can be negated by using the speaker in antiphase to the noise.
Microphones These devices do work in reverse as microphones and although fairly inefficient could afford the same promise as their speaker counterparts - namely the lack of mass means that the lack of inertia would reduce the microphones effect on the recorded sound. The extended frequency response would also be useful as per Carlsson 2018.
