Plasma Speaker, Plasma Chamber
GhostNull, Thu Sept 09 2010, 11:31AMHey
How are plasma chambers made?
What is structure of a plasma chamber like?
I've done reasearch on commerical plasma speakers and have found that higher quality plasma speakers utilise a helium filled charmber for the ionisation of gas. This I think means that they do not give off much if any ozone. It also I think means that they are better at producing sound, due to the lower break down voltage of Helium and the chamber helping to amplify and direct the sound. I'm going to be making a plasma speaker and I'm considering maaaaybe making a plasma chamber. Problem is, I haven't been able find any information on how plasma chambers work.
I've attached my idea for a plasma chamber.
Corrections would be welcome
Thanks
-Ken
Re: Plasma Speaker, Plasma Chamber
Patrick, Thu Sept 09 2010, 05:10PM
from my high school research i believe plasma is used for tweeter apps, due to low inertia, and therefore fast freq response, i dont know of an application of mid or low range freqs, it may be possible. you may be in uncharted territory. good luck!
Patrick, Thu Sept 09 2010, 05:10PM
from my high school research i believe plasma is used for tweeter apps, due to low inertia, and therefore fast freq response, i dont know of an application of mid or low range freqs, it may be possible. you may be in uncharted territory. good luck!
Re: Plasma Speaker, Plasma Chamber
Sulaiman, Thu Sept 09 2010, 05:37PM
I'm pretty sure the helium would diffuse away quite quickly,
you'd need some kind of helium-proof membrane across the open end to stop that.
The movement of the membrane would probably be less than one mm at practical frequencies.
Sulaiman, Thu Sept 09 2010, 05:37PM
I'm pretty sure the helium would diffuse away quite quickly,
you'd need some kind of helium-proof membrane across the open end to stop that.
The movement of the membrane would probably be less than one mm at practical frequencies.
Re: Plasma Speaker, Plasma Chamber
Patrick, Thu Sept 09 2010, 08:36PM
my chemistry book reveals: He to have a average speed of 1350 m/s @ STP
N2 = 520 m/s
O2 = 490 m/s
thus, his "horn" must be quite long to keep them from effusing, remember K-M theory suggests that the rate of effusion is inversely proportional to the square root of its mass. but he should try anyway.
based on hiscurrent idea, with short horn, the He may dissipate in a few seconds or a few hours, its hard to calculate.
also, including a membrane defeats the whole purpose of a low inertia speaker device.
Patrick, Thu Sept 09 2010, 08:36PM
my chemistry book reveals: He to have a average speed of 1350 m/s @ STP
N2 = 520 m/s
O2 = 490 m/s
thus, his "horn" must be quite long to keep them from effusing, remember K-M theory suggests that the rate of effusion is inversely proportional to the square root of its mass. but he should try anyway.
based on hiscurrent idea, with short horn, the He may dissipate in a few seconds or a few hours, its hard to calculate.
also, including a membrane defeats the whole purpose of a low inertia speaker device.
Re: Plasma Speaker, Plasma Chamber
radiotech, Thu Sept 09 2010, 08:47PM
The corona wind loudspeaker Gerald Shirley- June 11 1956 AES New York Section
DM Tombs Nature 176 923 ((1955) Dr Tombs thought radioactive needles would work best. Look at Shirleys curves. It was the 50's
Perhaps the internet will cough up these papers
radiotech, Thu Sept 09 2010, 08:47PM
The corona wind loudspeaker Gerald Shirley- June 11 1956 AES New York Section
DM Tombs Nature 176 923 ((1955) Dr Tombs thought radioactive needles would work best. Look at Shirleys curves. It was the 50's
Perhaps the internet will cough up these papers
Re: Plasma Speaker, Plasma Chamber
Patrick, Thu Sept 09 2010, 09:27PM
geez radiotech, you say "Radioactive" and "the 50's" like its a bad thing, love canal (pcb's), rivers burning (benzene) and Dr. Strangelove (nuclear war), you worry to much radiotech.
hmmm...radioacive needles...
EDIT: thats a great scan doc, the corona speaker is like a DeSeversky lifter, but made to be by directional.
Patrick, Thu Sept 09 2010, 09:27PM
radiotech wrote ...
Dr Tombs thought radioactive needles would work best... It was the 50's
Dr Tombs thought radioactive needles would work best... It was the 50's
geez radiotech, you say "Radioactive" and "the 50's" like its a bad thing, love canal (pcb's), rivers burning (benzene) and Dr. Strangelove (nuclear war), you worry to much radiotech.
hmmm...radioacive needles...
EDIT: thats a great scan doc, the corona speaker is like a DeSeversky lifter, but made to be by directional.
Re: Plasma Speaker, Plasma Chamber
radiotech, Thu Sept 09 2010, 11:25PM
The needles are fun as sources in cloud chambers. The Plasma design that GhostNull proposes is a horn and a horn is an acoustical transformer with throat loading issues.
We are not suggesting a nuclear powered Klipschorn to solve the response issues.
radiotech, Thu Sept 09 2010, 11:25PM
The needles are fun as sources in cloud chambers. The Plasma design that GhostNull proposes is a horn and a horn is an acoustical transformer with throat loading issues.
We are not suggesting a nuclear powered Klipschorn to solve the response issues.
Re: Plasma Speaker, Plasma Chamber
Adam Munich, Fri Sept 10 2010, 03:43AM
Often small neon bulbs will have thorium coated electrodes. You should also try thorated tungsten welding rods. It won't melt and may make a difference, be it ever so slight.
Adam Munich, Fri Sept 10 2010, 03:43AM
Often small neon bulbs will have thorium coated electrodes. You should also try thorated tungsten welding rods. It won't melt and may make a difference, be it ever so slight.
Re: Plasma Speaker, Plasma Chamber
Patrick, Fri Sept 10 2010, 04:24AM
Patrick, Fri Sept 10 2010, 04:24AM
radiotech wrote ...
The needles are fun as sources in cloud chambers.
This is a great point, I forgot that radiotech!The needles are fun as sources in cloud chambers.
Re: Plasma Speaker, Plasma Chamber
GhostNull, Fri Sept 10 2010, 09:58AM
Thanks for the Replies,
Looks like the helium diffusing would be the biggest problem, but in the final product there would no problem having a canister of helium to countinually top up the helium in the chamber unless I get heaps of helium diffusing.
And as for thorated tungsten welding rods, I think it would be more trouble than it's worth. From what I've seen tungsten, espcially with impureities is very hard to work and I haven't done any real metal work before. My plasma speaker it's probally going to be Dr. Kilovolt's circuit and even if it's not I doubt I'll go over 200w, it's not going to be a kW SGTC, so I don't think melting will be a problem. The amount of thorium in weld rods will most likely have little effect as you said, Grenadier. So thorated tungsten welding rods would be more trouble than it's worth. but hey, I could be wrong
My main concern is about the construction of the plasma chamber and making sure it sufficiently holds the helium.
I'm thinking of making the chamber by:
1. Making an open box out of some non-conductive material,
2. Lining it with plaster of paris
3. Drilling holes for electrodes and horn
4. Placing a piece of glass on for a veiwing window
5. Sealing it all up with...something, Suggestions?
My ideas for materials at the moment are:
Plexi for the structural box, since it's widely availible and easily workable. Any suggestions?
Steel for the electrodes, since it's tough, widely availible and workable. Any possible other metals that are easily workable and durable?
As for the horn I'm thinking one from a gramma phone with the curl in it would be good. The curl would help hold the helium and mean I could have the horn facing outward rather than down.
Could maybe another gas be used instead of Helium?
Suggestions would be great.
Thanks
-Ken
GhostNull, Fri Sept 10 2010, 09:58AM
Thanks for the Replies,
Looks like the helium diffusing would be the biggest problem, but in the final product there would no problem having a canister of helium to countinually top up the helium in the chamber unless I get heaps of helium diffusing.
And as for thorated tungsten welding rods, I think it would be more trouble than it's worth. From what I've seen tungsten, espcially with impureities is very hard to work and I haven't done any real metal work before. My plasma speaker it's probally going to be Dr. Kilovolt's circuit and even if it's not I doubt I'll go over 200w, it's not going to be a kW SGTC, so I don't think melting will be a problem. The amount of thorium in weld rods will most likely have little effect as you said, Grenadier. So thorated tungsten welding rods would be more trouble than it's worth. but hey, I could be wrong
My main concern is about the construction of the plasma chamber and making sure it sufficiently holds the helium.
I'm thinking of making the chamber by:
1. Making an open box out of some non-conductive material,
2. Lining it with plaster of paris
3. Drilling holes for electrodes and horn
4. Placing a piece of glass on for a veiwing window
5. Sealing it all up with...something, Suggestions?
My ideas for materials at the moment are:
Plexi for the structural box, since it's widely availible and easily workable. Any suggestions?
Steel for the electrodes, since it's tough, widely availible and workable. Any possible other metals that are easily workable and durable?
As for the horn I'm thinking one from a gramma phone with the curl in it would be good. The curl would help hold the helium and mean I could have the horn facing outward rather than down.
Could maybe another gas be used instead of Helium?
Suggestions would be great.
Thanks
-Ken
Re: Plasma Speaker, Plasma Chamber
Patrick, Sat Sept 11 2010, 04:12AM
why did you fisrt specify helium? was your choice merely a desire for a noble gas to limit eletrode side reactions?
Patrick, Sat Sept 11 2010, 04:12AM
why did you fisrt specify helium? was your choice merely a desire for a noble gas to limit eletrode side reactions?
Re: Plasma Speaker, Plasma Chamber
GhostNull, Sat Sept 11 2010, 07:05AM
I mentioned helium because that's what appearres to be used in most plasma speakers. I'm sure exactly why helium is used but I put my thoughts down on the orginal post
GhostNull, Sat Sept 11 2010, 07:05AM
I mentioned helium because that's what appearres to be used in most plasma speakers. I'm sure exactly why helium is used but I put my thoughts down on the orginal post
Re: Plasma Speaker, Plasma Chamber
radiotech, Sat Sept 11 2010, 08:53AM
The sound, say 1 metre from the opening of your speaker is compression and rarefaction of air mollecules, as is all sound.
How does the He plasma modulated by the audio get coupled to the air in the horn throat?
radiotech, Sat Sept 11 2010, 08:53AM
The sound, say 1 metre from the opening of your speaker is compression and rarefaction of air mollecules, as is all sound.
How does the He plasma modulated by the audio get coupled to the air in the horn throat?
Re: Plasma Speaker, Plasma Chamber
GhostNull, Sat Sept 11 2010, 11:31AM
To be honest I never really understood precisely how plasma speakers work. Maybe someone with better knowledge could explain *looks at Dr. Kilovolt*
My current understanding is that plasma speakers work by varying current through the arc,
by doing this it causes the intensity of the plasma to change
The rapidly varying plasma/arc causes the compression and rarefaction of air molecules
The He molecules would interact with the normal air molecules passing on the sound. Ah I see, since the He is less dense than normal air it will give the sound a higher pitch, just like when people talk with helium.
Thanks =D
I guess that means I would need compensation kind of compensation =/ Any ideas?
GhostNull, Sat Sept 11 2010, 11:31AM
To be honest I never really understood precisely how plasma speakers work. Maybe someone with better knowledge could explain *looks at Dr. Kilovolt*
My current understanding is that plasma speakers work by varying current through the arc,
by doing this it causes the intensity of the plasma to change
The rapidly varying plasma/arc causes the compression and rarefaction of air molecules
The He molecules would interact with the normal air molecules passing on the sound. Ah I see, since the He is less dense than normal air it will give the sound a higher pitch, just like when people talk with helium.
Thanks =D
I guess that means I would need compensation kind of compensation =/ Any ideas?
Re: Plasma Speaker, Plasma Chamber
radiotech, Mon Sept 13 2010, 02:40AM
Ghostnull Wrote.
The He molecules would interact with the normal air molecules passing on the sound. Ah I see, since the He is less dense than normal air it will give the sound a higher pitch, just like when people talk with helium.
I dont know if that follows.
An AC signal, like a sin tone has to find a way to move the
air in a bipolar way. In a moving coil loudspeaker the polarity
comes from the attraction/repulsion of the magnet to the moveable coil. Leaving the iron pole piece in place, if the magnet is taken away, the speaker will still work but double frequency of the the
acoustic.It goes into a square law mode where the current has to both generate a field in the pole as well as in the coil. The electrostatic speaker analogy is similar, only the polarizing is done by the DC bias onto which the AC is modulated.
So that would be a starting point, what mode of induction heats the gas? Now you have a gas on ions. That is an electrical conductor. From there you could reverse engineer a magnetohydrodynamic generator.
You could start with a propane jet, and a way to seed the flame and experiment with a MHD. to lay the foundations of making your plasma emit sound. The internet knows how these classlab kits work
if you can get it to tell.
btw Gramaphone horns sounded lousy untill telco types found out some physics and fixed them. Your's wont I hope.
radiotech, Mon Sept 13 2010, 02:40AM
Ghostnull Wrote.
The He molecules would interact with the normal air molecules passing on the sound. Ah I see, since the He is less dense than normal air it will give the sound a higher pitch, just like when people talk with helium.
I dont know if that follows.
An AC signal, like a sin tone has to find a way to move the
air in a bipolar way. In a moving coil loudspeaker the polarity
comes from the attraction/repulsion of the magnet to the moveable coil. Leaving the iron pole piece in place, if the magnet is taken away, the speaker will still work but double frequency of the the
acoustic.It goes into a square law mode where the current has to both generate a field in the pole as well as in the coil. The electrostatic speaker analogy is similar, only the polarizing is done by the DC bias onto which the AC is modulated.
So that would be a starting point, what mode of induction heats the gas? Now you have a gas on ions. That is an electrical conductor. From there you could reverse engineer a magnetohydrodynamic generator.
You could start with a propane jet, and a way to seed the flame and experiment with a MHD. to lay the foundations of making your plasma emit sound. The internet knows how these classlab kits work
if you can get it to tell.
btw Gramaphone horns sounded lousy untill telco types found out some physics and fixed them. Your's wont I hope.
Re: Plasma Speaker, Plasma Chamber
Patrick, Mon Sept 13 2010, 03:15AM
Patrick, Mon Sept 13 2010, 03:15AM
radiotech wrote ...
Ghostnull Wrote.
The He molecules would interact with the normal air molecules passing on the sound. Ah I see, since the He is less dense than normal air it will give the sound a higher pitch, just like when people talk with helium.
I dont know if that follows.
yeah, the purpose of a tweeter is to give the high freqs as the mids, and woofers, find it difficult to move that fast. the plasma tweeter doesnt provide a difference in tone, its just like a piezo, you dont need compensation. ghost null failed to understant my point in the previous post. its not at all like inhaling a balloon's helium and getting a squirells voice.Ghostnull Wrote.
The He molecules would interact with the normal air molecules passing on the sound. Ah I see, since the He is less dense than normal air it will give the sound a higher pitch, just like when people talk with helium.
I dont know if that follows.
Re: Plasma Speaker, Plasma Chamber
okk, Mon Sept 13 2010, 08:45AM
Hello all friends:
This is a good topic, that I interested in for a period.
As a sound source, the plasma flame enveloped by a chamber, connected to a horn, a plasma tweeter built.
In the traditional plasma tweeter with chamber (made in last 50-60's and used up to now), they did not fill any He. And the modern commercial plasma speakers(for example Acapella or Corona in europe) also did not fill any He. Actually they make O3 very little, because the voltage for keeping corona is very low (hundreds volts), so they can be survival.
But the tesla coil project gives much higher voltage, so it'll make much more O3.
I think the key-point of chambered plasma tweeter is chamber itself. I have not find any Patent about chamber of modern commercial plasma speakers. Somebody can recommend something to me?
Thanks.
okk, Mon Sept 13 2010, 08:45AM
Hello all friends:
This is a good topic, that I interested in for a period.
As a sound source, the plasma flame enveloped by a chamber, connected to a horn, a plasma tweeter built.
In the traditional plasma tweeter with chamber (made in last 50-60's and used up to now), they did not fill any He. And the modern commercial plasma speakers(for example Acapella or Corona in europe) also did not fill any He. Actually they make O3 very little, because the voltage for keeping corona is very low (hundreds volts), so they can be survival.
But the tesla coil project gives much higher voltage, so it'll make much more O3.
I think the key-point of chambered plasma tweeter is chamber itself. I have not find any Patent about chamber of modern commercial plasma speakers. Somebody can recommend something to me?
Thanks.
Re: Plasma Speaker, Plasma Chamber
GhostNull, Mon Sept 13 2010, 10:22AM
How did I misunderstand it? ='(
GhostNull, Mon Sept 13 2010, 10:22AM
Patrick wrote ...
radiotech wrote ...
Ghostnull Wrote.
The He molecules would interact with the normal air molecules passing on the sound. Ah I see, since the He is less dense than normal air it will give the sound a higher pitch, just like when people talk with helium.
I dont know if that follows.
yeah, the purpose of a tweeter is to give the high freqs as the mids, and woofers, find it difficult to move that fast. the plasma tweeter doesnt provide a difference in tone, its just like a piezo, you dont need compensation. ghost null failed to understant my point in the previous post. its not at all like inhaling a balloon's helium and getting a squirells voice.Ghostnull Wrote.
The He molecules would interact with the normal air molecules passing on the sound. Ah I see, since the He is less dense than normal air it will give the sound a higher pitch, just like when people talk with helium.
I dont know if that follows.
How did I misunderstand it? ='(
Re: Plasma Speaker, Plasma Chamber
Patrick, Mon Sept 13 2010, 02:24PM
its not the He that gives influences the sound, dont bother using it.
Patrick, Mon Sept 13 2010, 02:24PM
its not the He that gives influences the sound, dont bother using it.
Re: Plasma Speaker, Plasma Chamber
GhostNull, Tue Sept 14 2010, 08:25AM
Then why do they use it in some commerical speakers?
I guess it's not worth the trouble in that case.
Thanks...
GhostNull, Tue Sept 14 2010, 08:25AM
Then why do they use it in some commerical speakers?
I guess it's not worth the trouble in that case.
Thanks...
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