[mugdecoffee]

I remember reading an article linked from here about plasma tweeters where basically a flame was used to put ions in the air and then a coil changed the electric field thus making the ions in the air move to make noise (music). They apparently sounded amazing since there were no physical properties of the driver to worry about such as ringing or dampening. It basically worked like electrostatic headphones but instead of moving the charged membrane, it moved charged air. I may be a little off on the details but I think the overall idea is correct.

The drawbacks were that it needed a constant flame and that it could only move small amounts of air so it was limited to higher frequencies.

Today I stumbled on this article: New 'fan' design has no moving parts - The Tech Report where somehow researchers have figured out how to make a small fan using an electric field and no moving parts. The article says a 1cc module could cool a laptop which suggests it moves enough air to be useful as a headphone driver. Am I crazy or wrong somewhere? Has anyone else heard about this? Know of any other motionless driver designs?

 

[digger945]

Might sound OK, but what about the soundstaging, and would it be enough to fulfill the bass dept.?

Did you notice the one guy's reply with "Ionic Breeze" ca. 1990's?

Makes me think of magnetohydrodynamic drive on "Hunt for Red October"(Caterpillar drive I think they called it).

Interesting.

 

[jnewman]

Quote:

Originally Posted by digger945 /img/forum/go_quote.gif Makes me think of magnetohydrodynamic drive on "Hunt for Red October"(Caterpillar drive I think they called it).

While the book was fictional, the drive is real (albeit probably not actually practical for a sub)... I made one in high school physics class.

 

[Emooze]

Edit: Never mind, read that all wrong.

The concept is interesting but will it be able to move air back and forth rapidly enough for higher frequencies? I imagine a larger one would be great for subwoofers...

 

[Omega]

Been around a long time, in some incarnation or another.

The Rubens' tube is always awesome:
YouTube - Rubens Tube

(Yes, I know the Rubens' tube is a visualization, not a sound-producing device, but you know you liked the video!)

"Moving air" can be a misleading way to think of sound transducer mechanics. It must create a compression wave. Waves make tones, music, etc..."moving air" makes thumps. Cows move air daily, but seldom make music.

 

[Emooze]

Hmm, I guess I should have said, will the device be able to move fast enough to produce audible tones?

But if you say it's been around for a while and no one has yet used it to make sound, either can't or we have some unimaginative people in charge.

 

[jnewman]

Quote:

Originally Posted by Emooze /img/forum/go_quote.gif Hmm, I guess I should have said, will the device be able to move fast enough to produce audible tones? But if you say it's been around for a while and no one has yet used it to make sound, either can't or we have some unimaginative people in charge.

Nelson Pass made some speakers with plasma tweeters a while back. I recall he wrote that they sounded quite good but he just about died from ozone poisoning using them in an area without sufficient ventilation.

Fast isn't the problem, they apparently make super tweeters but can't do lows/mids. The thread linked below has some of Nelson Pass's comments as well as comments by some others who have built or used them.

http://www.diyaudio.com/forums/showthread.php?t=1841

 

[Uncle Erik]

Quote:

Originally Posted by jnewman /img/forum/go_quote.gif Fast isn't the problem, they apparently make super tweeters but can't do lows/mids.

You can get mids and lows with plasma. However, that requires truly frightening levels of power and ozone production. And probably a very large electric bill, as well.

 

[Emooze]

Quote:

Originally Posted by jnewman /img/forum/go_quote.gif Nelson Pass made some speakers with plasma tweeters a while back. I recall he wrote that they sounded quite good but he just about died from ozone poisoning using them in an area without sufficient ventilation. Fast isn't the problem, they apparently make super tweeters but can't do lows/mids. The thread linked below has some of Nelson Pass's comments as well as comments by some others who have built or used them. Pass plasma speaker history? - diyAudio

I was commenting on the ion fan device.

 

[jnewman]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif You can get mids and lows with plasma. However, that requires truly frightening levels of power and ozone production. And probably a very large electric bill, as well.

I'm sure you're right.