I have built to finished sizes so far, aprox 3.5" X 9.5" and a size 4 times bigger at 7.75" X 22".
Although I would like to build a much larger panel such as a 4 foot tall one, I really don't have the need for it right now, But, I will do so evenualy.
Both size panels sound the same with the exception of a slightly exended lower end response due to the larger width.
My next build will be an even larger width of aprox 11.5" X 20" in order to utilize the full width of my mylar which is 12.5" and to check the stability of the diagphram at such a width.
The choice of height is only because it was a piece of material that was left over from the previous builds.
I have tried different thickness of spacers aswell ranging from .050" to .1" with up to +/- .020" range for other differences on both panel sizes.
I personaly like the larger spacing as I like to get down to the 100hz to 200hz range and have had no problems compensating for this by using a higher bias voltage.
A thinner spacing is more desireable if you are crossing over at about 500hz and above.
I choose the window screen method mainly for the cost of materials.
I also felt that it might give me a stronger and more uniform static field across the surface area of the stator due to the smaller holes while maitaining a good open area.
Aswell as reducing the hemholtz effect and possible ringing of using solid metal panels that are preforated.
My very first panels were preforated but the open area was quite low and this degraded the performance quite considerably.
I do wish to try a build with preforated metal panels one day with the proper open area to compare to when cost is not a problem, As they have been made using this technique with great sucsess.
It is just a cost factor for me as the price of steel keeps going up, where as window screen is less than $.25 per square foot.
The window screen method in my case resulted in a very open and nonrestricted sound as I have not heard any panels using preforated metal yet, with the only exception of some Martin Logans and they where the first esl's that I have heard just before I did my first build.
I used common enamel spray paint for my stator coating and also polyurethene before I knew anything about paints and I had found out the hard way not to mix the two as one causes the other to bubble and the becomes a problem.
I have found that just plain clear acyrlic is about the best and easiest to use with the possiblity of using a primer,
Primer contains talc and talc has great characteristics as an insulating material and also has a high dielectric constant which is a desirable effect.
There have been many discussions on this as well and will be the choice for my next build to see how well it will work.
The little panels that I am currently using have been double powder coated and then later (after seven years) resealed using clear acyrlic and has been the best coating I have done so far.
But powder coating has its own set of issues and is probably the cheapest method.
But, it takes some experimentation and alot of trial and error to get it right.
But my little panels using this method perform incredibly and are the best to date.
The spray paint method is probably the easiest and most convienent method and good results can be had when properly done and I will determine this on the next build.
However it can be abit costly as it takes quite a bit of cans in order to get a sufficient thickness of coating depending on the bias an drive voltages you plan on using and it is what is holding me up at the moment.
I need more paint!
Also, It is suggested not to use any paint that has a pigment except for the posiblity of one layer for color and thats it!
As most pigments are titanium dioxide and it conducts very well at high voltages.
Also black that uses carbon as a pigment.
There are a few discussions on this, But no test data, and, it is something that needs to be investigated further.
I have this problem with my first panel as I used white spray paint to coat them with and have had to combat the problem with some clear.
But the coating is already quite thick and the newer coats of clear reduced the hole sizes of the screen and reduced the open area considerabley.
So I started a new process using the proper combination of paint types.
That is my basic method in detail and I hope this information is of any help to the beginner diy'ers in the construction of diy esl's.
As I stated, earlier, I will start a new thread showing the details with pictures when I start my next build.
Enjoy and Good Luck. jer
Although I would like to build a much larger panel such as a 4 foot tall one, I really don't have the need for it right now, But, I will do so evenualy.
Both size panels sound the same with the exception of a slightly exended lower end response due to the larger width.
My next build will be an even larger width of aprox 11.5" X 20" in order to utilize the full width of my mylar which is 12.5" and to check the stability of the diagphram at such a width.
The choice of height is only because it was a piece of material that was left over from the previous builds.
I have tried different thickness of spacers aswell ranging from .050" to .1" with up to +/- .020" range for other differences on both panel sizes.
I personaly like the larger spacing as I like to get down to the 100hz to 200hz range and have had no problems compensating for this by using a higher bias voltage.
A thinner spacing is more desireable if you are crossing over at about 500hz and above.
I choose the window screen method mainly for the cost of materials.
I also felt that it might give me a stronger and more uniform static field across the surface area of the stator due to the smaller holes while maitaining a good open area.
Aswell as reducing the hemholtz effect and possible ringing of using solid metal panels that are preforated.
My very first panels were preforated but the open area was quite low and this degraded the performance quite considerably.
I do wish to try a build with preforated metal panels one day with the proper open area to compare to when cost is not a problem, As they have been made using this technique with great sucsess.
It is just a cost factor for me as the price of steel keeps going up, where as window screen is less than $.25 per square foot.
The window screen method in my case resulted in a very open and nonrestricted sound as I have not heard any panels using preforated metal yet, with the only exception of some Martin Logans and they where the first esl's that I have heard just before I did my first build.
I used common enamel spray paint for my stator coating and also polyurethene before I knew anything about paints and I had found out the hard way not to mix the two as one causes the other to bubble and the becomes a problem.
I have found that just plain clear acyrlic is about the best and easiest to use with the possiblity of using a primer,
Primer contains talc and talc has great characteristics as an insulating material and also has a high dielectric constant which is a desirable effect.
There have been many discussions on this as well and will be the choice for my next build to see how well it will work.
The little panels that I am currently using have been double powder coated and then later (after seven years) resealed using clear acyrlic and has been the best coating I have done so far.
But powder coating has its own set of issues and is probably the cheapest method.
But, it takes some experimentation and alot of trial and error to get it right.
But my little panels using this method perform incredibly and are the best to date.
The spray paint method is probably the easiest and most convienent method and good results can be had when properly done and I will determine this on the next build.
However it can be abit costly as it takes quite a bit of cans in order to get a sufficient thickness of coating depending on the bias an drive voltages you plan on using and it is what is holding me up at the moment.
I need more paint!
Also, It is suggested not to use any paint that has a pigment except for the posiblity of one layer for color and thats it!
As most pigments are titanium dioxide and it conducts very well at high voltages.
Also black that uses carbon as a pigment.
There are a few discussions on this, But no test data, and, it is something that needs to be investigated further.
I have this problem with my first panel as I used white spray paint to coat them with and have had to combat the problem with some clear.
But the coating is already quite thick and the newer coats of clear reduced the hole sizes of the screen and reduced the open area considerabley.
So I started a new process using the proper combination of paint types.
That is my basic method in detail and I hope this information is of any help to the beginner diy'ers in the construction of diy esl's.
As I stated, earlier, I will start a new thread showing the details with pictures when I start my next build.
Enjoy and Good Luck. jer
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Hi,
No!
The phase angle was, is and will always be -90° for a pure capacitance and +90° for a pure inductance. Just the value of the impedance changes.
See Wikipedia "electrical impedance" and "electrical reactance"
Helpful might be to draw the complex plane diagram in which the X-axis represents the real part of the complex impedance and the Y-axis represents the imaginary part of the complex impedance. The vector Z representing the (complex) impedance value is drawn begiining in the centre with a length of |Z| Ohms and a phase angle of Phi. Calculation of the real part and the imaginary part is just a matter of simple trigonometry. Real part is |Z|*cos(phi), the Imaginary part is |Z|*sin(phi). The same diagram can also be used to show how the complex current is put together. Setting the real and imaginary values into a relationship Cos(phi)/Sin(phi) then gives the afore mentioned current-relationship depending on the phase angle.
If You rotate the Vector Z (or current vector I) from -90° (capacitance) over 0° (resistor) to 90° (inductance) You see how the real part starts from 0 (at -90°) reaches its maximum at 0° and going back to 0 at +90°, while the imaginary part starts at minimum crossing the 0 and eventually reaching the maximum.
So changing the capacitance value just changes the length of the impedance vector pointing 90° downwards. It doesn´t change the phase angle Phi. Only a additional resistive component can change Phi to values higher -90° (or lower than |-90°|).
jauu
Calvin
No!
The phase angle was, is and will always be -90° for a pure capacitance and +90° for a pure inductance. Just the value of the impedance changes.
See Wikipedia "electrical impedance" and "electrical reactance"
Helpful might be to draw the complex plane diagram in which the X-axis represents the real part of the complex impedance and the Y-axis represents the imaginary part of the complex impedance. The vector Z representing the (complex) impedance value is drawn begiining in the centre with a length of |Z| Ohms and a phase angle of Phi. Calculation of the real part and the imaginary part is just a matter of simple trigonometry. Real part is |Z|*cos(phi), the Imaginary part is |Z|*sin(phi). The same diagram can also be used to show how the complex current is put together. Setting the real and imaginary values into a relationship Cos(phi)/Sin(phi) then gives the afore mentioned current-relationship depending on the phase angle.
If You rotate the Vector Z (or current vector I) from -90° (capacitance) over 0° (resistor) to 90° (inductance) You see how the real part starts from 0 (at -90°) reaches its maximum at 0° and going back to 0 at +90°, while the imaginary part starts at minimum crossing the 0 and eventually reaching the maximum.
So changing the capacitance value just changes the length of the impedance vector pointing 90° downwards. It doesn´t change the phase angle Phi. Only a additional resistive component can change Phi to values higher -90° (or lower than |-90°|).
jauu
Calvin
Update on copper mesh at Lee Valley:
I didn't buy it. It was a very loose weave, and it wouldn't stretch or take any tension at all before it would start to unravel. Not suitable for ESL use.
BUT, the copper tape I did buy. It's about 0.005" thick, so it has some strength to it.
AND...Michael's (hobby/gift store) does have diamond pattern perforated copper mesh in various thickness' and hole size. I'll check this out when I get the chance and I'll post pics.
I didn't buy it. It was a very loose weave, and it wouldn't stretch or take any tension at all before it would start to unravel. Not suitable for ESL use.
BUT, the copper tape I did buy. It's about 0.005" thick, so it has some strength to it.
AND...Michael's (hobby/gift store) does have diamond pattern perforated copper mesh in various thickness' and hole size. I'll check this out when I get the chance and I'll post pics.
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Correct me if I'm wrong, but I believe it is only the resistive part of the radiation impedance that can generate useful acoustic output, not the resistive losses in the ESL capacitance or resistance in the transformer windings or crossover parts.
Hi,
Naaa, just kiddin´
I´ve been thinking for a while -well, some years actually- of an ESL made only from clear transparent materials. I think that a ´glass-ESL´ could really gain some interest, because it would look even less like a loudspeaker as a common ESL. I know how to do and what materials to use and where and how to manufacture, but it´ll be very costly and my boss is unwilling to throw the bucks at it right now.
jauu
Calvin
Go to jail! Don´t pass Go! Don´t collect the money!
Naaa, just kiddin´
I´ve been thinking for a while -well, some years actually- of an ESL made only from clear transparent materials. I think that a ´glass-ESL´ could really gain some interest, because it would look even less like a loudspeaker as a common ESL. I know how to do and what materials to use and where and how to manufacture, but it´ll be very costly and my boss is unwilling to throw the bucks at it right now.
jauu
Calvin
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Hi,
well Sennheiser´s Orpheus featured glass stator electrodes afaik.
Holes formed by an etching process into the electrodes and then made electrically conductive. The renowned Schott company produced the electrodes.
But for a large electrode glass would very probabely much to sensitive against breaking. I´d rather think of a plastik material instead, maybe clear acrylics.
jauu
Calvin
well Sennheiser´s Orpheus featured glass stator electrodes afaik.
Holes formed by an etching process into the electrodes and then made electrically conductive. The renowned Schott company produced the electrodes.
But for a large electrode glass would very probabely much to sensitive against breaking. I´d rather think of a plastik material instead, maybe clear acrylics.
jauu
Calvin
I would agree that acrylic would be better stator material choice than glass for a large ESL. Thermal expansion coefficient of Mylar and acrylic are nearly the same. Glass is 6 to 8 times less, so diaphragm tension would change more with temperature.
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Hi,
etching acrylics? No way. Getting it to conduct should be easy.
But don´t know yet if I´d experience the same problems Final had.
Besides the current stress on the conducting diaphragm they had the mechanical vibrational stress. I assume that that was the reason for the failures they experienced. I hope that a clear conductive stator -without the vibrational stress- will be longtime stable.
jauu
Calvin
etching acrylics? No way. Getting it to conduct should be easy.
But don´t know yet if I´d experience the same problems Final had.
Besides the current stress on the conducting diaphragm they had the mechanical vibrational stress. I assume that that was the reason for the failures they experienced. I hope that a clear conductive stator -without the vibrational stress- will be longtime stable.
jauu
Calvin
Tin oxide is what licron uses as conducter.
Etching does two things (IMHO as I am no chemist) 1# it causes a rougher surface in order to bond too.
2# due to this increased surface area, it allows a more thicker material to to be deposited therefore reducing the surface area resistance.
But acrylic has a rarther long chain of molecules, and it is because of this factor that makes it so durable.
And like mylar makes it very difficult to bond to.
jer
Etching does two things (IMHO as I am no chemist) 1# it causes a rougher surface in order to bond too.
2# due to this increased surface area, it allows a more thicker material to to be deposited therefore reducing the surface area resistance.
But acrylic has a rarther long chain of molecules, and it is because of this factor that makes it so durable.
And like mylar makes it very difficult to bond to.
jer
I also have had Issue's with aluminium has a stator material after it has been powder coated It becomes very brittle and breaks very easily due to the mechanical stress.
Not to mention the corrosion problems after seven years of deliberate hard abuse from using aluminium as a stator material.
I sealed that problem with a few coates of spray acyrlic.
I have been thinking about using glass but the issues of it being so britttle have set me back a bit as getting enough heat to work with it is not an issue.
I think that it would definitely work for a smaller size panel without a hitch.
Those are my thoughts on the subject and hopefully I might be able to investigate this further.
jer
Not to mention the corrosion problems after seven years of deliberate hard abuse from using aluminium as a stator material.
I sealed that problem with a few coates of spray acyrlic.
I have been thinking about using glass but the issues of it being so britttle have set me back a bit as getting enough heat to work with it is not an issue.
I think that it would definitely work for a smaller size panel without a hitch.
Those are my thoughts on the subject and hopefully I might be able to investigate this further.
jer
Hi friends,
I'm sorry if this is a bit off the topic. But, what impact do you think that the open area, hole size and thickness of stator have on the sounding of an ESL? Do you think that more open area sounds better? Do you think that thinner stator sounds better? Do you think that given the same open area, stators with smaller holes sound better than stators with larger holes?
These are two photos of the stator of a new flagship headphone from Stax. Notice the big opening in the middle of the stator. What and why do you think they do that for?
Wachara C.
I'm sorry if this is a bit off the topic. But, what impact do you think that the open area, hole size and thickness of stator have on the sounding of an ESL? Do you think that more open area sounds better? Do you think that thinner stator sounds better? Do you think that given the same open area, stators with smaller holes sound better than stators with larger holes?
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
These are two photos of the stator of a new flagship headphone from Stax. Notice the big opening in the middle of the stator. What and why do you think they do that for?
Wachara C.
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