Future - Massless - plasma tweeter

Besides the few surviving designs based on much earlier work there has been nothing new in the massless speaker world that has made it past the theoretical or prototype level in over the last 20 years. That's not to say it has been a stagnant area with many attempts being made to take products to market, a lot of research and patents galore.

One notable rise in the patent world is in Asia, especially the number of Chinese patents around massless speakers has ballooned. Having spent considerable time wading through many of them it looks on the face of it that most, if not all, are patenting designs that have been patented long ago in the western continents. They are difficult to search and understand for someone like me from the English speaking world, but there is the occasional nugget in there.

Notable more recent patents include the corona wind wire based speaker of Howard 1997, Sony's own plasma tweeter application 2008 (not granted) and a microwave based plasma tweeter (can't see anything to go wrong there) from Wenjie 2018.

There is a propagation of two plasma speaker/tweeter circuit designs in the web sphere. It's difficult to find an original source for either of them but the schematics are common and even available as kits from Amazon etc. They are shown off in numerous videos and many websites with designs.

The first is based on an old TV flyback transformer and simply points two electrodes (just bare wire or screws) at each other. The second uses a tesla coil, from small finger size up to megavolt monsters with an open air electrode (sometimes called a singing tesla coil, zeusaphone or thoramin). Both of these designs use a switching power supply and typically a 555 timer or other PWM controller to modulate it with an audio signal, perhaps closest to the IML DVL Digiplasma. These are great for demonstrations and experiments and may lead to more massless speakers being designed eventually, but they remain a curiosity and are not high fidelity at the moment.

There are some DIY versions of higher fidelity plasma tweeters shown online, some successfully turned into hi-fi quality kit in use alongside some audiophile setups. They are typically based on Klein's Ionophone or his Magnat tweeter.

The world has changed a lot from Klein's time, information is much more available (and misinformation) and the speed of development and opportunity for investment has increased. Components for high voltage use are now much cheaper and with a wider variety of devices. There's been a few small projects on Kickstarter, plasma kits etc. and some efforts that look like a massless speaker but often with little substance behind them.

A few more recent examples that were almost commercialised include:

Kronos Air Technologies, 2008, made a very promising looking corona wind design in a 2008 ESA paper and a 2007 patent. Nothing more.

WaveIon was a Czech design in 2014 demoed at CES, Infocomm and Axpona. It appears to be a small corona wind based vertical stick with a dynamic driver filling the bass, although their marketing speak may put this in more flowery terms. The website is still up. They were seeking funding and it looks like they didn't get any.

SonArc in 2016 from Ireland did obtain €50,000 of European grant funding for further research. They got a patent in 2020 and have released nothing more since. It was going to use the surface glow discharge plasma effect to try and achieve a wider frequency response. Although papers from Potts and Diver (2007) and Roth, Dai et.al. (2005) suggest this as a possibility, how practical this would be in reality and from several safety angles could be questioned. This is one that was also hot on the marketing speak and was obviously quite convincing judging by the funding given.

Some academic work from 2020 appears to be around using ionic speakers in active noise damping systems for ducts. In these papers released from 2020 to 2023 and a patent in 2023, Stanislav Sergeev demonstrates a working ionic speaker in a specific application. There is a deeper look at this work as it is interesting in many ways beyond the actual technology - see the complete Case Study.

Work around laser based plasma sound has increased recently, especially with regard to the use of it in military applications from 2018 onwards. Although known as a physical principle for decades, using recent developments in femtosecond pulse lasers a plasma can be formed in air and then modulated by a second laser at audio frequencies and very high sound levels can be created on or near a remote target. Also separate research from Kaleris et al from 2019 to 2024 uses femtosecond pulse lasers for more accurate sound reproduction using digital signals to modulate the lasers.

It would seem our journey ends here but as technology improves, things that were impossible in the past become easier and so new avenues can be explored.

The typical ways in which massless speakers are designed are covered in the Design section of this site.

Plasma Speaker and Tweeter Ionophone Information

Plasma Loudspeakers

Ionovac and Plasmatronic

Plasma Tweeters

Plasma Speaker

Corona Wind or Ionic and Ion Speakers