Hi Steve
There is another material that I think would prove to be of interest for a DML Panel and I would have been quite happy to acquire samples and offer them for trial.
The material is no longer being sent to the UK and the last Boards that I know were available were brought in during late 2021.
The material is produced by a German Board Manufacturer called Delignit.
A range of their Products are are produced from Boards that have been Plies of less than 1mm thick and are then compressed to 50% compression.
The Laminations when the Board is produced are less than 0.5mm.
The Board Produced is almost non reactive in it its properties, it is not effected by environmental changes making it a very stable material.
The Two Boards from Delignit that are looking to have a attraction are Panzerholz (Panzer Meaning Armour and this P'holz is a Bulletproof Material) and Festholz (Fest meaning Hard/Solid ) these products are available in the thickness of 4mm - 100mm.
The Material has a mass of 1400kg per Cubic Metre.
Panzerholz will have for the B25 Material 20 layers per Centimetre thickness.
Festholz is available in a Longitudinal Grain Orientation or a Intersected 90 Degree Grain Orientation and can have as many as 25 Plies per Centimetre thickness.
The cost of a 4mm piece could be quite affordable and transit costs should not be too prohibitive.
It would be great if such a material was available to be sourced and offered up for a trial.
There is another material that I think would prove to be of interest for a DML Panel and I would have been quite happy to acquire samples and offer them for trial.
The material is no longer being sent to the UK and the last Boards that I know were available were brought in during late 2021.
The material is produced by a German Board Manufacturer called Delignit.
A range of their Products are are produced from Boards that have been Plies of less than 1mm thick and are then compressed to 50% compression.
The Laminations when the Board is produced are less than 0.5mm.
The Board Produced is almost non reactive in it its properties, it is not effected by environmental changes making it a very stable material.
The Two Boards from Delignit that are looking to have a attraction are Panzerholz (Panzer Meaning Armour and this P'holz is a Bulletproof Material) and Festholz (Fest meaning Hard/Solid ) these products are available in the thickness of 4mm - 100mm.
The Material has a mass of 1400kg per Cubic Metre.
Panzerholz will have for the B25 Material 20 layers per Centimetre thickness.
Festholz is available in a Longitudinal Grain Orientation or a Intersected 90 Degree Grain Orientation and can have as many as 25 Plies per Centimetre thickness.
The cost of a 4mm piece could be quite affordable and transit costs should not be too prohibitive.
It would be great if such a material was available to be sourced and offered up for a trial.
John .
The panel you describe is quite heavy and hard, so I am a bit suspicious of how it will sound ?
I do prefer smaller lighter panels for myself.
I've had a bit of a rethink about panel weight lately ,and now regard any material heavier than eps, as being heavy.
Eps, is the only material I have tested so far that has that fast dynamic sound ,that I like.
I've even started to think that the higher grades are getting too heavy.
They measure more like a ply panel.
Don't get me wrong , my heavier panels do sound good, it's just that for me the eps takes it to another level if used correctly.
Clamping or damping an eps panel kills the dynamics and atmosphere , which is what makes them special to me.
The small 1mm wood veneer ,card, corrugated cardboard, all have similar properties and responses to the canvas panel ,so are options too.
I'm going to have a listen to my naked canvas panel with the 50x50 mix of pva on, and might add a neat coating after that, depending on what I find ?
Steve.
Yesterday I looked in my profile and found my email address was wrong ? So have updated it.
Strange.
The panel you describe is quite heavy and hard, so I am a bit suspicious of how it will sound ?
I do prefer smaller lighter panels for myself.
I've had a bit of a rethink about panel weight lately ,and now regard any material heavier than eps, as being heavy.
Eps, is the only material I have tested so far that has that fast dynamic sound ,that I like.
I've even started to think that the higher grades are getting too heavy.
They measure more like a ply panel.
Don't get me wrong , my heavier panels do sound good, it's just that for me the eps takes it to another level if used correctly.
Clamping or damping an eps panel kills the dynamics and atmosphere , which is what makes them special to me.
The small 1mm wood veneer ,card, corrugated cardboard, all have similar properties and responses to the canvas panel ,so are options too.
I'm going to have a listen to my naked canvas panel with the 50x50 mix of pva on, and might add a neat coating after that, depending on what I find ?
Steve.
Yesterday I looked in my profile and found my email address was wrong ? So have updated it.
Strange.
Hi Steve
I have had a look at EPS Foam and can see the material weighs between 11kg - 47Kg per Cubic Metre.
This is a substantial decrease in the mass of the materials in comparison to the one I referred to.
I can see why there are queries on the suitability, with the Delignit densified wood board types I suggested.
I have had a look at EPS Foam and can see the material weighs between 11kg - 47Kg per Cubic Metre.
This is a substantial decrease in the mass of the materials in comparison to the one I referred to.
I can see why there are queries on the suitability, with the Delignit densified wood board types I suggested.
I disappeared for a bit, life kicked my ***.
Anyway...I have my first shipment of transducers. I don't have the panel material I've been planning to test so I just have one transducer out and double sided taking it to various things and listening to different music and talking and comparing to various speakers around the house.
Holy crap.
I just put my Dayton "steel spring balanced" exciter on the wall next.to my TV below my fairly nice Yamahas mounted on the wall as a right channel and paired it with an old Bose bookshelf speaker I inherited from my mom as the left channel. I have two sources set up and able to flip back and forth between speakers.
The wall is cheap wood paneling from the 80s that's painted over, probably 4mm thick. It sounds better than any of the speakers I'm comparing to.
Subwoofer off to keep it fair which is working against the Yamahas as their bass is weak and the WALL has them beat on kick. Trying not to let that influence me and just think of the kids and highs as I will have my sub handling everything below 180 anyway. Wow.
I might try and make the wall a speaker except the guest bedroom is on the other side of the wall and the volume is about the same in that room lol
Anyway...I have my first shipment of transducers. I don't have the panel material I've been planning to test so I just have one transducer out and double sided taking it to various things and listening to different music and talking and comparing to various speakers around the house.
Holy crap.
I just put my Dayton "steel spring balanced" exciter on the wall next.to my TV below my fairly nice Yamahas mounted on the wall as a right channel and paired it with an old Bose bookshelf speaker I inherited from my mom as the left channel. I have two sources set up and able to flip back and forth between speakers.
The wall is cheap wood paneling from the 80s that's painted over, probably 4mm thick. It sounds better than any of the speakers I'm comparing to.
Subwoofer off to keep it fair which is working against the Yamahas as their bass is weak and the WALL has them beat on kick. Trying not to let that influence me and just think of the kids and highs as I will have my sub handling everything below 180 anyway. Wow.
I might try and make the wall a speaker except the guest bedroom is on the other side of the wall and the volume is about the same in that room lol
Johnnog.
today I was going though listening to my panel selection, and ended up with my eps panels.
such power and detail ,but they do need my TLS to back them up , just the same as all my other panels.
you seem to have large spaces for panels , maybe you should try an eps 70 grade .
wickes sell an 8x4ft panel for about £10 ,it used to be £8 and rising fast.
you can get 4 2x4ft panels or 1 2x4ft and 2 6x2 ft panels from one sheet.
you can buy them in 8x2ft sizes but they cost almost as much.
it's the cheapest and best panel you can buy ,and improve.
steve.
today I was going though listening to my panel selection, and ended up with my eps panels.
such power and detail ,but they do need my TLS to back them up , just the same as all my other panels.
you seem to have large spaces for panels , maybe you should try an eps 70 grade .
wickes sell an 8x4ft panel for about £10 ,it used to be £8 and rising fast.
you can get 4 2x4ft panels or 1 2x4ft and 2 6x2 ft panels from one sheet.
you can buy them in 8x2ft sizes but they cost almost as much.
it's the cheapest and best panel you can buy ,and improve.
steve.
Hello Steve,
Is it this General Purpose Polystyrene EPS70 - 2400mm x 1200mm x 25mm product you suggest ?
EPS70 EPS is a 15kg/m³ density. Correct?
One year ago starting with DML, I thought to this material which is common in DIY store but I didn't go far with it.
What is the design you would suggest to any beginner with it ? Sanding, PVA coating, suspension, exciter position...
When I came home with one such panel, my wife was more happy than with the XPS. The product was mainly white with some spot of colors but not fully satisfying for sitting in the living room like that (not speaking about the 2x4ft dimensions). I had some experience in XPS painting to have them white with some basic acrilyc but the process to do it seems a bit too randomly to me : which painting, which quantity... do you have some additional advice on that?
Thank you
Christian
Christian.
Yes eps 70grade.
Some years ago now wickes started using poor quality eps, which had holes in the surface , so my supply dried up !
This was another reason I started playing around with other materials.
I used to make a concave dome shape in the centre of the exciter area to allow more direct sound through the panel.
it looked like a cone shape on the front, and probably acted like a cone too.
This improved the presence in front of the panel ,and gave a more intimate sound.
Sanding yes, but this is a pain in the neck with a 6ft panel !
Then apply a 50x50 mix of pva and water, this mix will run off, if the panel is not sanded !
If you feel the need to add more you can, I even experimented with thinned vinyl silk paint, which softens the sound, if it, is preferred ?
The pictures show some very old panels, the one on the left is sanded , but not coated or thinned in the centre, white dust still falls from The panel after all these years !
The 6ft panel on th left is standing on the floor on dish sponges , but will start to walk if heavy low frequencies are used !
my preferred eps mounting I use is 1 inch dish sponges,(softened) they affect the sound very little ,and do not buzz , they also stop the panel spinning around every time I walk past them.
If you do attempt this panel ,I am always willing to give advice.
WARNING.
Do not attempt to collect this size panel on a windy day, a slight breeze will send you flying across the car park ,trying to dodge all the cars and pedestrians 😱😀
Very embarrassing !!!
This link shows the damage caused to the panel (bottom right) when it was ripped out of my hand, I glued this piece back with pva.
https://www.audiocircle.com/index.php?action=gallery;area=browse;image=45743
Steve.
Yes eps 70grade.
Some years ago now wickes started using poor quality eps, which had holes in the surface , so my supply dried up !
This was another reason I started playing around with other materials.
I used to make a concave dome shape in the centre of the exciter area to allow more direct sound through the panel.
it looked like a cone shape on the front, and probably acted like a cone too.
This improved the presence in front of the panel ,and gave a more intimate sound.
Sanding yes, but this is a pain in the neck with a 6ft panel !
Then apply a 50x50 mix of pva and water, this mix will run off, if the panel is not sanded !
If you feel the need to add more you can, I even experimented with thinned vinyl silk paint, which softens the sound, if it, is preferred ?
The pictures show some very old panels, the one on the left is sanded , but not coated or thinned in the centre, white dust still falls from The panel after all these years !
The 6ft panel on th left is standing on the floor on dish sponges , but will start to walk if heavy low frequencies are used !
my preferred eps mounting I use is 1 inch dish sponges,(softened) they affect the sound very little ,and do not buzz , they also stop the panel spinning around every time I walk past them.
If you do attempt this panel ,I am always willing to give advice.
WARNING.
Do not attempt to collect this size panel on a windy day, a slight breeze will send you flying across the car park ,trying to dodge all the cars and pedestrians 😱😀
Very embarrassing !!!
This link shows the damage caused to the panel (bottom right) when it was ripped out of my hand, I glued this piece back with pva.
https://www.audiocircle.com/index.php?action=gallery;area=browse;image=45743
Steve.
Attachments
Hello Steve
Thanks a lot for your kind answer.
I had already almost all those elements in mind... except the basic material is EPS70 and perhaps the dish sponges.
The goal of my question was to create a kind of "reference post" for this design so that all the current readers know about it without collecting all the information in the past of this very long thread.
I will store the link in the "history file".
In France, this EPS grade (15kg/m³) is easily available in DIY store 1200x600x20mm so a little bit thinner.
Important to know that any additional layer like painting will modify the sound.
While testing the XPS panels, I took inspiration from your dome shape to reduce the HF.
Christian
Christian.
a 20mm panel should be fine
The large panel in my room weighs about 500gm ,which is actually 170cm x 60cm x 25mm.
This picture shows a couple of my old panels with the weights written on them ,I hope you can see ?
The first yellow panel on the left is a 15mm thick panel coated in vinyl silk and is 71g.
The second is a low grade 10mm thick eps with no coating and only weighs 14g.
The third is the same low grade with a coating of pva, it has a pva coated fabric dome which is adding some extra grams .
The fourth is a 25mm eps panel heavily coated in vinyl silk ,it has no parallel sides , and with the cone in the centre of the coil, I even angled The edges, I got a bit carried and !
The paint adds about 100g !
I added the second picture to show a panel that was with other panels stashed behind the curtains, out of the way of my wife's prying eyes.
Speaking of my wife, I can hear her upstairs ,doing French lessons on her phone app.
She has just booked the Eurostar for September to stay at a friend's houes,if all goes well ?
She is very happy at the moment ,so I had better hide the panels quickly 😁
You can mould these panels to the sound you prefer, heavier ,stiffer, softer ,the choice is yours.
Steve.
a 20mm panel should be fine
The large panel in my room weighs about 500gm ,which is actually 170cm x 60cm x 25mm.
This picture shows a couple of my old panels with the weights written on them ,I hope you can see ?
The first yellow panel on the left is a 15mm thick panel coated in vinyl silk and is 71g.
The second is a low grade 10mm thick eps with no coating and only weighs 14g.
The third is the same low grade with a coating of pva, it has a pva coated fabric dome which is adding some extra grams .
The fourth is a 25mm eps panel heavily coated in vinyl silk ,it has no parallel sides , and with the cone in the centre of the coil, I even angled The edges, I got a bit carried and !
The paint adds about 100g !
I added the second picture to show a panel that was with other panels stashed behind the curtains, out of the way of my wife's prying eyes.
Speaking of my wife, I can hear her upstairs ,doing French lessons on her phone app.
She has just booked the Eurostar for September to stay at a friend's houes,if all goes well ?
She is very happy at the moment ,so I had better hide the panels quickly 😁
You can mould these panels to the sound you prefer, heavier ,stiffer, softer ,the choice is yours.
Steve.
Attachments
I only have access to one grade of XPS sheet, the Dow-corning purplish pink 4 foot by 8 foot sheets.i want to buy some and experiment with it. I have options for 1/2 inch (12.5mm), 1 inch (25mm), 2 inch (50mm) and 3 inch....where should I start?
I'm planning to have very large panels. Since my minivan was totaled recently I only have a small sedan to transport from the store so my first cut will have to be at the store...other than that I have space to do a full sheet if I wanted. I was thinking maybe 1 inch? That seems popular. It seems 1/2 Inch would be better for a very small panel.
I also have the idea to skin a panel with very thin woven fiberglass to make it much stiffer and provide a harder surface. I assume 1/2 inch or even thinner would be the right answer there?
Waiting on delivery of 4mm foam core carbon fiber panels but given the month I'm having Id like to throw myself into this a bit now rather than next week.
I'm planning to have very large panels. Since my minivan was totaled recently I only have a small sedan to transport from the store so my first cut will have to be at the store...other than that I have space to do a full sheet if I wanted. I was thinking maybe 1 inch? That seems popular. It seems 1/2 Inch would be better for a very small panel.
I also have the idea to skin a panel with very thin woven fiberglass to make it much stiffer and provide a harder surface. I assume 1/2 inch or even thinner would be the right answer there?
Waiting on delivery of 4mm foam core carbon fiber panels but given the month I'm having Id like to throw myself into this a bit now rather than next week.
So done some more printing experiments.
Some 3d print technicalities to bore you all with:
Since the single layer 0.1 mm skin was sensitive and easily ripped, I tried to print double 0.06 mm thick layers instead. Usually it is recommended to have extra thick initial layer, since consumer level printers with decent size beds usually is a bit uneven. So even a 0.1mm initial layer can be a challenge, and 0.2mm is a more typical first layer height. Some printers (Prusa, the Apple of 3D printing) even force minimum 0.15 height for first layer. But with double 0.06 layers printed in different directions I get a much more homogenous skin, and only 0.12mm, so 0.02mm thicker than before. So he plates will stand remounting of the exciter, and perhaps it gives a bit lower distortion. The absolute minimum layer height (limited by the stepper motors resolution) should be 0.04mm, so can try to push it even more.
I tried printing the top separately. My hope was to either glue or heat it on.
Glue didn't really seem viable. It seems to need a quite thick and gooey layer of glue to stick, and probably a vacuum as well to make sure it is stuck at every cell. At least my attempts resulted in some spots not being stuck, causing terrible distortion. And in the end you are probably not getting a lighter plate anyway compared to printing it in one piece if you have to add several grams of glue. I will revisit if I get vacuum equipment and a good epoxy to play around with sandwich composites, but one of the allures of printing is not having to go through the expense and hassle of that.
Heating it on was just a really bad idea. The material will shrink and deform when heated...especially a 0.12 mm thin film. Should have known since I attempted annealing a plate earlier to increase stiffness, also with less than ideal results.
But, lowering the layer height, I can also get a bit thinner bit more solid top layer, so printing in one go might not be so bad.
I suspected that some of my initial measurements was off due to exciter mounting issues which caused me to discard the PLA+ as useless due to a really bad drop off above 3-4k, but I noticed results have been more consistent when using tape. So printed a 3.8mm plate with the PLA+ in the same dimensions (295x205mm) but using the lower layer height.
Here is FR (green) and spectral contamination (orange) and noisefloor (grey):
FR is similar to the other printed plates.
For the spectral contamination I simply used multitone 1/10 dec in REW. I tried with one of the files @homeswinghome linked to, with similar result. My graph looks very different though...do you have the actual file you used Christian so I can compare?
So hard to say much about the spectral contamination without a reference, but will make the test on some different panels.
Some 3d print technicalities to bore you all with:
Since the single layer 0.1 mm skin was sensitive and easily ripped, I tried to print double 0.06 mm thick layers instead. Usually it is recommended to have extra thick initial layer, since consumer level printers with decent size beds usually is a bit uneven. So even a 0.1mm initial layer can be a challenge, and 0.2mm is a more typical first layer height. Some printers (Prusa, the Apple of 3D printing) even force minimum 0.15 height for first layer. But with double 0.06 layers printed in different directions I get a much more homogenous skin, and only 0.12mm, so 0.02mm thicker than before. So he plates will stand remounting of the exciter, and perhaps it gives a bit lower distortion. The absolute minimum layer height (limited by the stepper motors resolution) should be 0.04mm, so can try to push it even more.
I tried printing the top separately. My hope was to either glue or heat it on.
Glue didn't really seem viable. It seems to need a quite thick and gooey layer of glue to stick, and probably a vacuum as well to make sure it is stuck at every cell. At least my attempts resulted in some spots not being stuck, causing terrible distortion. And in the end you are probably not getting a lighter plate anyway compared to printing it in one piece if you have to add several grams of glue. I will revisit if I get vacuum equipment and a good epoxy to play around with sandwich composites, but one of the allures of printing is not having to go through the expense and hassle of that.
Heating it on was just a really bad idea. The material will shrink and deform when heated...especially a 0.12 mm thin film. Should have known since I attempted annealing a plate earlier to increase stiffness, also with less than ideal results.
But, lowering the layer height, I can also get a bit thinner bit more solid top layer, so printing in one go might not be so bad.
I suspected that some of my initial measurements was off due to exciter mounting issues which caused me to discard the PLA+ as useless due to a really bad drop off above 3-4k, but I noticed results have been more consistent when using tape. So printed a 3.8mm plate with the PLA+ in the same dimensions (295x205mm) but using the lower layer height.
Here is FR (green) and spectral contamination (orange) and noisefloor (grey):
FR is similar to the other printed plates.
For the spectral contamination I simply used multitone 1/10 dec in REW. I tried with one of the files @homeswinghome linked to, with similar result. My graph looks very different though...do you have the actual file you used Christian so I can compare?
So hard to say much about the spectral contamination without a reference, but will make the test on some different panels.
Anyone have experience with EPS with graphite added?
It seems quite popular in Europa at least, and BASF manufactures it under the brand Neopor:
https://neopor.de/portal/load/fid1225157/Neopor_professional brochure.pdf
The ones available here is rated as S100 and is 20 kg/m³
EDIT: Here is some specs: https://www.basf.com/us/documents/e...ch-bulletin-platinum-ci-specs-performance.pdf
It seems quite popular in Europa at least, and BASF manufactures it under the brand Neopor:
https://neopor.de/portal/load/fid1225157/Neopor_professional brochure.pdf
The ones available here is rated as S100 and is 20 kg/m³
EDIT: Here is some specs: https://www.basf.com/us/documents/e...ch-bulletin-platinum-ci-specs-performance.pdf
Narenaud.
My epoxy 5mm panels are 23 1/2inches x 33 1/2 inches ,is this a very small panel ?
I'd go for the half inch myself if that was all I could get, it would be interesting to see how the thin fibreglass skin changes the xps performance.
And just how rigid it becomes ?
Steve.
My epoxy 5mm panels are 23 1/2inches x 33 1/2 inches ,is this a very small panel ?
I'd go for the half inch myself if that was all I could get, it would be interesting to see how the thin fibreglass skin changes the xps performance.
And just how rigid it becomes ?
Steve.
Ive just come from wickes and the 8x4 ft eps is £10 and the 8x2ft is £8, twice as much for £2 !
But the 2ft is easier to cut up to fit into the car.
I also managed to get a free 9mm eps panel similar in size to the 14g panel which was slightly larger at 11mm.
The free panel is a 70grade I believe, and weighs 24g.
I'm going to coat both of these in pva and see how the sound and performance compares .
The low grade panel floats down in the air like a feather.
Am I going to notice any difference in the sound between these two panels ?
Which is going to measure better ?
I have suspicions.
Can't wait
Steve.
But the 2ft is easier to cut up to fit into the car.
I also managed to get a free 9mm eps panel similar in size to the 14g panel which was slightly larger at 11mm.
The free panel is a 70grade I believe, and weighs 24g.
I'm going to coat both of these in pva and see how the sound and performance compares .
The low grade panel floats down in the air like a feather.
Am I going to notice any difference in the sound between these two panels ?
Which is going to measure better ?
I have suspicions.
Can't wait
Steve.
Thank you Steve
This confirms the density range and the fact the paint can be an important portion of the total weight.
I can belief you. The point is to how to proceed, what modifies what... without some dozens of tests (more?)
Christian
Hello Leob,
Good think you tested the spectral contamination test. When I did it, it was in comparison between a classical full range (a Visaton FRS8) and different panels. The first point should be to check the level used which is perhaps not so easy because it needs some mic calibration. I am also not aware of a kind of metric extraction. If somebody knows about it...
Before a having a better framework, you might perhaps use a standard loudspeaker as reference.
By the way, with your post I understand that I am not using the last REW version. I have the 5.19 while I suppose you use the 5.20 which has a multitone generator; So next task for me to update REW.
You will find attached two mdat from my records : one is the reference FRS8, the second is an acrylic. Let me know if you want others.
Christian
Leob
What let you to think this material is a good candidate? I just go through the specs but I have now idea... apart seeing its density is low which is a good point.