Hi,
I have built 1 stator made of perforated, powder coated steel plates, d/s = 2 mm and stator size is 1000mm X 350mm. Spacers are sectioned in 4 sections of 250X350mm
I find the size impractical, and using steel stators gives some challenges when it comes to insulation, fastening to supports etc. Gluing the diaphragm is also a challenge - it requires a slow-curing glue that will glue to spacers and diaphragm.
I have designed a new stator in standard A4 (297X210mm) that will be made out of lexan, and coated with a conductive coating on the inner side.
I will make 6-10 of these stators and make an array, electrically connected in parallel.
My question is, how will this affect frequency response? The new stators will be about the same size as one section of the big stator, but total size of 4-5 of these panels will be larger.
Thanks for any input!
Regards,
Bent
I have built 1 stator made of perforated, powder coated steel plates, d/s = 2 mm and stator size is 1000mm X 350mm. Spacers are sectioned in 4 sections of 250X350mm
I find the size impractical, and using steel stators gives some challenges when it comes to insulation, fastening to supports etc. Gluing the diaphragm is also a challenge - it requires a slow-curing glue that will glue to spacers and diaphragm.
I have designed a new stator in standard A4 (297X210mm) that will be made out of lexan, and coated with a conductive coating on the inner side.
I will make 6-10 of these stators and make an array, electrically connected in parallel.
My question is, how will this affect frequency response? The new stators will be about the same size as one section of the big stator, but total size of 4-5 of these panels will be larger.
Thanks for any input!
Regards,
Bent
Hi Bent,
stator dimensions affect the frequency range in two ways:
1 - The smallest dimension sets the frequency at which bass roll-off starts, due to cancellation of the back & front waves. You only get more bass if you put two 'stacks' of modular panels right next to each other side-by-side.
2 - The panel area determines the capacitance, and this affects the frequency range insofar as a larger panel presents a lower reactance to your amplifier at high frequencies.
Making the panel area higher, but not wider, is a good thing. It does not extend low frequencies but gives you more max SPL. It also makes your speaker work more like a line source, which means that the SPL will not decay so fast with increasing listening distance.
To sum it up: if you make N panel modules, you have two options:
1 - Try to keep the smallest dimension big, to get more bass --> make your panels more or less square.
2 - Strive for a line source to get better SPL at your listening position and to minimize room interaction --> make narrow floor-to-ceiling panels.
3 - Make another N modules + amps and do both
HTH
Kenneth
stator dimensions affect the frequency range in two ways:
1 - The smallest dimension sets the frequency at which bass roll-off starts, due to cancellation of the back & front waves. You only get more bass if you put two 'stacks' of modular panels right next to each other side-by-side.
2 - The panel area determines the capacitance, and this affects the frequency range insofar as a larger panel presents a lower reactance to your amplifier at high frequencies.
Making the panel area higher, but not wider, is a good thing. It does not extend low frequencies but gives you more max SPL. It also makes your speaker work more like a line source, which means that the SPL will not decay so fast with increasing listening distance.
To sum it up: if you make N panel modules, you have two options:
1 - Try to keep the smallest dimension big, to get more bass --> make your panels more or less square.
2 - Strive for a line source to get better SPL at your listening position and to minimize room interaction --> make narrow floor-to-ceiling panels.
3 - Make another N modules + amps and do both
HTH
Kenneth
Stator conductive coating
Hi,
the plastic stators will be machined this week, and I am looking into what conductive coating to use on the stators, and what to insulate the conductive coating with.
As conductive coating I plan to use Graphite Dry Lubrication, a spray on graphite that dries and forms a uniform and wear-safe layer. I am unsure about the electrical properties for this product.
As insulation for preventing arching, I will apply layers of acrylic clear coating. An alternative is spray-on circuit board insulation.
The stator is 49% open, 4mm thick and made of a rigid lexan-type plastic.
Any suggestions on other products that will serve the purpose and is easily obtainable and DIY-friendly?
Regards,
Bent
Hi,
the plastic stators will be machined this week, and I am looking into what conductive coating to use on the stators, and what to insulate the conductive coating with.
As conductive coating I plan to use Graphite Dry Lubrication, a spray on graphite that dries and forms a uniform and wear-safe layer. I am unsure about the electrical properties for this product.
As insulation for preventing arching, I will apply layers of acrylic clear coating. An alternative is spray-on circuit board insulation.
The stator is 49% open, 4mm thick and made of a rigid lexan-type plastic.
Any suggestions on other products that will serve the purpose and is easily obtainable and DIY-friendly?
Regards,
Bent
Last edited:
I have been doing much research on stator coatings lately.
I have found that clear spray acrylic is probably the best choice to use with around 1,5kv/mil breakdown factor with the exception of super corona dope wich claims a breakdown factor of 3.1kv/mil and 4kv/mil if oven cured.
Don't use a paint with any pigment as I had used white and had found the even the thickest areas conducted more than than the thinnest areas did around 5kv and above.
I think I remember reading that black may have been a better choice but white was what I had on hand at the time.
I've been toying with the idea of using a coat or few of a gray primer using talc as a pigment or use a white using titanium oxide or dioxide(each sucsessively having a higher dielectric constant) and then sealing with several coats of clear to get the desired thickness and insulating factor.
This procedure may work to raise the dielectric constant ,slightly or even significantly, and posibily raising efficiancy.
I am still in the process of sorting out my elctronics issues, amplifier is one and and getting my bias supply to maintain a constant voltage over 8kv with a load is the other.
Once these issues are ironed out I will start building some new panels again to investigate different stator coatings in more detail. jer
I have found that clear spray acrylic is probably the best choice to use with around 1,5kv/mil breakdown factor with the exception of super corona dope wich claims a breakdown factor of 3.1kv/mil and 4kv/mil if oven cured.
Don't use a paint with any pigment as I had used white and had found the even the thickest areas conducted more than than the thinnest areas did around 5kv and above.
I think I remember reading that black may have been a better choice but white was what I had on hand at the time.
I've been toying with the idea of using a coat or few of a gray primer using talc as a pigment or use a white using titanium oxide or dioxide(each sucsessively having a higher dielectric constant) and then sealing with several coats of clear to get the desired thickness and insulating factor.
This procedure may work to raise the dielectric constant ,slightly or even significantly, and posibily raising efficiancy.
I am still in the process of sorting out my elctronics issues, amplifier is one and and getting my bias supply to maintain a constant voltage over 8kv with a load is the other.
Once these issues are ironed out I will start building some new panels again to investigate different stator coatings in more detail. jer
I am curious,Bentl,as to why you have chosen a graphite based material to use as a stator?
You can get many different types sprayable metal coatings such as copper or nickel and such.
Although you can get graphite coatings with a very low resistance, my only concern is the adhesive ability to the insulative coating and stator base material might not be very good and could seperate when flexed, while handling. jer
You can get many different types sprayable metal coatings such as copper or nickel and such.
Although you can get graphite coatings with a very low resistance, my only concern is the adhesive ability to the insulative coating and stator base material might not be very good and could seperate when flexed, while handling. jer
Hi, I am going to test graphite - as it contains little else than graphite which I know is conductive and adheres to smooth surfaces very well.
I have also bought copper- and silverloaded spray paint, but I am not so sure if this will work very well. (theese are normal spary-paints, not designet specially to be conductive)
I will make a test with all coatings, just take a sheet of plastic and add a row of connectors on two oposite ends. Then mask of identical strips and apply coating over 2 connectors with each coating and measure conductivity/resistance to see. Then add clear coat to see if that messes ut things.
I will also test zinc spray used to repair galvanic zinc coatings to see if that works.
Testing will commence on sunday (due to a disturbing element called work..)
Regards
Bent
I have also bought copper- and silverloaded spray paint, but I am not so sure if this will work very well. (theese are normal spary-paints, not designet specially to be conductive)
I will make a test with all coatings, just take a sheet of plastic and add a row of connectors on two oposite ends. Then mask of identical strips and apply coating over 2 connectors with each coating and measure conductivity/resistance to see. Then add clear coat to see if that messes ut things.
I will also test zinc spray used to repair galvanic zinc coatings to see if that works.
Testing will commence on sunday (due to a disturbing element called work..)
Regards
Bent
Hi Wachara
I guess there is different types of zinc spray; I know there are types are conductive which can be applied and then arch-weld or spotweld through it.
But, I will start testing with graphite spray, copper spray and nickel spray to see how it works.
The zinc spray that I have in mind is 98,7% zinc, and should be conductive. But there will be 1,3% adhesives, which may or man not work as an insulation.
I will post the test results during the weekend, and hopefully have a few complete ESL elements assembled during next week.
I guess there is different types of zinc spray; I know there are types are conductive which can be applied and then arch-weld or spotweld through it.
But, I will start testing with graphite spray, copper spray and nickel spray to see how it works.
The zinc spray that I have in mind is 98,7% zinc, and should be conductive. But there will be 1,3% adhesives, which may or man not work as an insulation.
I will post the test results during the weekend, and hopefully have a few complete ESL elements assembled during next week.
Try this company Plating Kits Electroplating Kits Aluminum Anodizing Kits Powder Coating Systems Metal Polishing And Buffing Supplies - Caswell Inc.
They do have what you are looking for ,but I'm not sure about shipping,check with them to find out,also M.G.Chemicals comes to mind.
I used aluminium foil tape on this project with great results http://www.diyaudio.com/forums/planars-exotics/158115-material-esl-2.html#post2076459
I once tried copper plating rubber cement coated with graphite wifh okay results.
which brings me wanting to try that again but by using one of my licron products as a base,I will try this sometime in the furture.
Also try some electron microscope supply companies you will find some really neat stuff there,thats were I found my super thin .06mil mylar.
If you do a search on conductive coatings you will find alot,I once find a company that had different grades of spray on graphite (and other metals) that ranged from 10ohm or less to as high as 100kohm to 1meg ohms or so that I was considering for a ribbon speaker project.
If I can think of or find anything else on my travels I will post it for you. jer
They do have what you are looking for ,but I'm not sure about shipping,check with them to find out,also M.G.Chemicals comes to mind.
I used aluminium foil tape on this project with great results http://www.diyaudio.com/forums/planars-exotics/158115-material-esl-2.html#post2076459
I once tried copper plating rubber cement coated with graphite wifh okay results.
which brings me wanting to try that again but by using one of my licron products as a base,I will try this sometime in the furture.
Also try some electron microscope supply companies you will find some really neat stuff there,thats were I found my super thin .06mil mylar.
If you do a search on conductive coatings you will find alot,I once find a company that had different grades of spray on graphite (and other metals) that ranged from 10ohm or less to as high as 100kohm to 1meg ohms or so that I was considering for a ribbon speaker project.
If I can think of or find anything else on my travels I will post it for you. jer
Hi,
I think I have an idea here!
I will spray the acrylic plates with spray glue, and stick a layer of regular household alu foil on it.
Then a layer of 3M protective plastic foil for insulation. That should take care of both the electrical conductivity and the insulation.
I will route the holes after applying the alu foil and 3M plastic. (Or; my girlfriend will - and she's not happy about routing all the holes - but she loves me ;-)
I also have alu foil tape, but it is only 50mm wide so it will take 3,4 stripes to cover the "active" area of the stator.
Regards,
Bent
I think I have an idea here!
I will spray the acrylic plates with spray glue, and stick a layer of regular household alu foil on it.
Then a layer of 3M protective plastic foil for insulation. That should take care of both the electrical conductivity and the insulation.
I will route the holes after applying the alu foil and 3M plastic. (Or; my girlfriend will - and she's not happy about routing all the holes - but she loves me ;-)
I also have alu foil tape, but it is only 50mm wide so it will take 3,4 stripes to cover the "active" area of the stator.
Regards,
Bent
I covered the aluminium with clear packing tape.
Then I used sodium hydroxide (lye)to etch the holes from the back side.
I then carefully removed the packing tape tape and coated it with clear acrylic except for the connection spots.
It seems that the plastic tape would get bound up in the machining bit ?jer
Then I used sodium hydroxide (lye)to etch the holes from the back side.
I then carefully removed the packing tape tape and coated it with clear acrylic except for the connection spots.
It seems that the plastic tape would get bound up in the machining bit ?jer
Hi,
Im not worried about that - normally all plastic is routed WITH a protective film on it - and it is only removed before assembly or bending. Stock sheets are supplied with protective film on both sides)
But it seems I will have to route the stators first and the apply the alu and protection; the router has a vacuum table and small piezes does tend to move especially if they are full of holes.
So I may have to cut 1500 holes it the alu and protection with a scalpel..
the echting technique worked good except that if the glue backing saluated to much around the edges it lifted the foil while trying to remove the clear tape ,this happened on one panel but I was able to save it.
May be you can route it with the foils already attached?
might this give a cleaner result? jer
May be you can route it with the foils already attached?
might this give a cleaner result? jer
Companies that do those big posters on the road sides will carve any outline on self-adhesive plastic film for you - laser... All you need then is to apply the film (or better say stencil) to your panel to beHi,
Im not worried about that - normally all plastic is routed WITH a protective film on it - and it is only removed before assembly or bending. Stock sheets are supplied with protective film on both sides)
But it seems I will have to route the stators first and the apply the alu and protection; the router has a vacuum table and small piezes does tend to move especially if they are full of holes.
So I may have to cut 1500 holes it the alu and protection with a scalpel..
Alex
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.