this is my take on a summary of a very interesting review. It's about Lansche Audio speakers which use plasma tweeters. There tweeters are extremely rare today and have been mystified to a certain degree, mostly because the last time manufacturers seriously tried to use them in speakers was in the 80s. This review in german magazine "Stereoplay" even contains an interview with Mr. Lansche himself !
I will not post the whole review, as I try to focus on those parts that are - in my opinion - the most interesting ones.
The idea of the mass-less ion tweeter came up for the first time in 1900, when british physicist William Du Bois experimented with his "singing electric arc". As time passed by, many enthusiasts tried to build tweeters according to this concept: at the end of the 70s, Dr. Alan Hill created quite some buzz in the United States with his take on the Ion tweeter. French ion-tweeter specialist Dr. Siegried Klein cooperated with Magnat in the 80s, which actually started a minor hype in Germany! At the same time Otto Braun in Saarbrücken experimented with his Corona-Tweeter. But even in the golden age of Hi-Fi massless tweeters never had their breakthrough...
Bottom line: At the time, plasma tweeters just couldn't play loud enough and emitted Ozone (O³) - simply put, the listening room started to smell quite unpleasantly after a few minutes.
In 1999, engineer Rüdiger Lansche aquired Otto Brauns patent and continued the development of the Corona tweeter. It works like this: An electric arc, about 8mm in size and glowing at 400 C°, resides inside a burning chamber. It oscillates at 27 Megahertz and creates an ionized gas field, which is the purplish/blueish flame one can see from the outside when looking at the center of the horn. This flame gets bigger or smaller according to the music signal, thus effectively causing air vibrations: sound...
(At this point I will leave out a lot of technical stuff and jump directly to how the No. 3.1 perfoms as a speaker, then I will go on to some additional info and finally the interview with Engineer Rüdiger Lansche.)
Sound is very cohesive. The typical problem of the 80s - light speed tweeter meets lame bass - is gone. It is however necessary to directly point the speakers at the listening position to enjoy these speakers to the fullest.
In direct comparison to our reference (in this price class), the Bowers & Wilkins 802 Diamond, the No. 3.1 turned out to be a really good speaker. In the end the Bowers played a tad fuller ,with richer colors and it also offered the higher maximum volume. But the Diamond tweeter was only second-rate against the Corona. This was a true shock for a convinced Diamond fanboy like me. Both tweeters offer insane resolution, but with the Lansche 3.1 finest details got to my ear in a more impulsive, direct and simply effortless manner.
Lansche Audio No. 3.1
18.500€ (recommended price)
W: 24cm H: 98cm D: 39cm
Suitable for rooms up to 40m²
Q: Mr. Lansche, you have been working for over 14 years on the Corona. What's so special about this technology?
A: Little to no resoncances, very impulse-prone as there is almost no mass and a huge frequency range. There's nothing better, at least nothing I know of.
Q: Many people are fascinated by the range. But how far does it really go? Where's the limit?
A: Even our microphones top out at 40 khz. But we sold a Corona to Bosch recently. They wanted a tweeter that can go to 60khz at a relatively high volume. Our Corona was the only tweeter that fulfilled that criteria. I believe it even goes to 150khz.
Q: But aren't there some disadvantages?
A: Depends on how you look at it. With a power amp that oscillates at 100khz a normal tweeter would have way too much impedance for anyhting to go wrong. But our Corona feels right at home there. This can be a serious problem with low quality amps. A different kind of problem is that absolute neutrality: some people are actually irritated when they listen to it for the first time - it sounds so pure.
Q: What about common problems such as low efficiency and Ozone?
A: Do you smell something? No, those days are definitely gone. And the 3.1 is no slouch, it can go as loud as most speakers of the same size can.
Q: If this concept is so superior, then why not go for an ion midrange driver?
A: It's definitely worth a shot. Maybe we can even suceed. But we will probably reach our limits soon, because all the problems of the Corona multiply when you try to make it bigger. Let me say it like this: We are working on it, but don't expect anything in the near future.
Edited by AManAnd88Keys - 2/25/14 at 12:12pm