Agree entirely!
Steve, I was really referring to how you would rank the panel materials you have tried in order of perceived audio quality
Eucy
Eucy.
The delay in answering this question, is me thinking how should i answer it ?
I use the recordings and let people make up their own minds, which saves me having to give my own opinion.
Although I must admit that all the recordings sound pretty similar , it is hard to tell the different materials apart , which is a good thing, I think ?
But the recordings are only to give an idea of the sound possible, it is impossible to give you the real in room experience, which far far better.
so your question is still valid.
so.
EPS has been my favourite for many years now, even though I don't regard it as a full range material, close as it is.
but the materials I would regard as full range I would roll them off at the same sort of frequency anyway, so is of no consequence to me.
the only panel I would now consider as a full range panel, is the surprise proplex, but it would have to be tested with a more powerful exciter.
the only Achilles heel might be the glues to use to attach the exciters, PVA is still holding on the exciters , but I know from tests that PVA is easy to snap off.
what glue will give a stronger lasting bond on polypropylene ?
as for sound quality, I would group this panel in with heavy panels(compared to EPS)
Ply , not my favourite but remains in this group.
1mm card.
1mm veneer.
3mm Crate ply ,which sounds better than it should, but still has problems to solve.
XPS would join this group if it was coated in epoxy,and it would become a heavier panel , PVA did improve the panel but not enough to satisfy.
The small card and veneer panels are only restricted in size, not the quality of sound they produce.
I would roll them off petty much the same as much larger panels.
It could be argued that they are an improvement as they are more of a point source with a better spaciality ?
The reason I have the EPS in a separate group is the lightness and delicate sound achievable with the huge dynamics and realism,
The crate ply moves in this direction and has a similar sound , but is not enough.
This is more of a generalisation of sound quality, as I am sure others will have their own idea of the sound they will prefer.
If you like the sound of the podiums for instance , I would group them in with the second group of heavy panels ,with a very good similar sound.
I don't think I want to add anymore, but am open to questions at any time.
Steve.
The delay in answering this question, is me thinking how should i answer it ?
I use the recordings and let people make up their own minds, which saves me having to give my own opinion.
Although I must admit that all the recordings sound pretty similar , it is hard to tell the different materials apart , which is a good thing, I think ?
But the recordings are only to give an idea of the sound possible, it is impossible to give you the real in room experience, which far far better.
so your question is still valid.
so.
EPS has been my favourite for many years now, even though I don't regard it as a full range material, close as it is.
but the materials I would regard as full range I would roll them off at the same sort of frequency anyway, so is of no consequence to me.
the only panel I would now consider as a full range panel, is the surprise proplex, but it would have to be tested with a more powerful exciter.
the only Achilles heel might be the glues to use to attach the exciters, PVA is still holding on the exciters , but I know from tests that PVA is easy to snap off.
what glue will give a stronger lasting bond on polypropylene ?
as for sound quality, I would group this panel in with heavy panels(compared to EPS)
Ply , not my favourite but remains in this group.
1mm card.
1mm veneer.
3mm Crate ply ,which sounds better than it should, but still has problems to solve.
XPS would join this group if it was coated in epoxy,and it would become a heavier panel , PVA did improve the panel but not enough to satisfy.
The small card and veneer panels are only restricted in size, not the quality of sound they produce.
I would roll them off petty much the same as much larger panels.
It could be argued that they are an improvement as they are more of a point source with a better spaciality ?
The reason I have the EPS in a separate group is the lightness and delicate sound achievable with the huge dynamics and realism,
The crate ply moves in this direction and has a similar sound , but is not enough.
This is more of a generalisation of sound quality, as I am sure others will have their own idea of the sound they will prefer.
If you like the sound of the podiums for instance , I would group them in with the second group of heavy panels ,with a very good similar sound.
I don't think I want to add anymore, but am open to questions at any time.
Steve.
Jaxboy.
Although it seems I have missed out the art panel, but basically it is a ply or crate ply in my case or whatever panel is used to mount the exciter on to the canvas.
But with an extended low end frequency.
On many of my recordings I mix and match the panels with one type of panel on one side and another type on the other side.
The canvas panel with the exciter mounted directly to the canvas is also in this group but with a reduced low end response.
The difference between this group is subtle and I am not sure if I could tell the difference from my recordings alone, especially when used with a sub.
But there are differences.
Steve.
Although it seems I have missed out the art panel, but basically it is a ply or crate ply in my case or whatever panel is used to mount the exciter on to the canvas.
But with an extended low end frequency.
On many of my recordings I mix and match the panels with one type of panel on one side and another type on the other side.
The canvas panel with the exciter mounted directly to the canvas is also in this group but with a reduced low end response.
The difference between this group is subtle and I am not sure if I could tell the difference from my recordings alone, especially when used with a sub.
But there are differences.
Steve.
Polypropylene is probably the most difficult plastic to glue...
The best way is to abrade the surface, then apply a primer to chemically open the surface, then glue
Still not perfect but better than otherwise
Here's one solution:
https://www.loctite-consumer.co.uk/...a-super-strength-adhesive-for-tough-jobs.html
Not sure how brittle the result will be.
I have a greenhouse with 4mm thick polycarbonate twin wall sheeting similar to Proplex/Corflute profile... feather weight and stiffer than polypropylene...has anyone tried it as a panel material?
Eucy
Thank you Steve
The reason is according to the basic modeling of DML in the papers, there is low pass filter between the exciter voice coil inductance and the resistance which is made mainly of the voice coil resistance, the mechanical resistance of the panel, the output resistance of the amplifier. For a given exciter inductance (0.1mH in our cases), a bigger resistance would give reject the cut off higher in the spectrum.
As a tube amp has an output resistance around 2 Ohms, I was wondering if there is something noticeable.
Christian
Hello
Not sure it will have an interest for the next realizations but as I introduced the idea... I made a short test with white egg on a piece of plywood.
I added salt (a good quantity) to the white before application and let it for the night. After this the white is fluid. I applied it with a brush on the wood.
The day after, I sanded the board with steel wool and then applied a highly diluted varnish.
On another piece, I directly apply the varnish.
I can't say without measurement if the plywood with the white is stiffer and if there is a difference in damping. By knotting the pieces with the finger, no obvious differences.
What is noticeable is the white really fill the grain. After it, the varnish is not absorbed by the wood like on the second sample. The surface remains smooth.
In the second sample, the varnish rise the grain. So some sanding is needed after the first layer.
If it can be a solution for some finishing where a polish is research, at this step, I don't see the interest for DML... To find an interest, to define the expectation of the varnish layer might be a step.
Christian
Not sure it will have an interest for the next realizations but as I introduced the idea... I made a short test with white egg on a piece of plywood.
I added salt (a good quantity) to the white before application and let it for the night. After this the white is fluid. I applied it with a brush on the wood.
The day after, I sanded the board with steel wool and then applied a highly diluted varnish.
On another piece, I directly apply the varnish.
I can't say without measurement if the plywood with the white is stiffer and if there is a difference in damping. By knotting the pieces with the finger, no obvious differences.
What is noticeable is the white really fill the grain. After it, the varnish is not absorbed by the wood like on the second sample. The surface remains smooth.
In the second sample, the varnish rise the grain. So some sanding is needed after the first layer.
If it can be a solution for some finishing where a polish is research, at this step, I don't see the interest for DML... To find an interest, to define the expectation of the varnish layer might be a step.
Christian
i have made another recording of another cup of coffee ,so that you can make up your own mind about how similar they sound, but this time on a 1mm veneer 6x9inch panel and a 1mm card and epoxy 6x9inch panel .
two different panel materials and a small size, so you can compare the sound to the 2ft proplex with the other materials.
the veneer is on the left, i rolled off the small panels at 114hz the low end driver rolls off at the usual 300hz.
you do not have to miss out on quality when using a small panel.
steve.
two different panel materials and a small size, so you can compare the sound to the 2ft proplex with the other materials.
the veneer is on the left, i rolled off the small panels at 114hz the low end driver rolls off at the usual 300hz.
you do not have to miss out on quality when using a small panel.
steve.
christian .
the affect the egg whites have on a thick heavy ply may not be that much ? but the affect on a 1mm card or veneer can be quite significant ,
i use pva on my small card and veneer panels and have experimented with epoxy ,to give the panels a bit of body .
they flap around too much without this coating, egg whites might be another option ? especially if it has a reduced weight when dry ?
i have just finished another packet of cereal, the box is 19cm x30cm this seems a good size to start with.
i think i will glue the two .5mm together with pva as usual as the egg whites will probably just soak away into the panel.
so i will end up with a 1mm x 19cmx30cm panel with pva in the middle and an egg whites coating.
i may do some tests with a scrap piece first and see how it goes.
steve.
the affect the egg whites have on a thick heavy ply may not be that much ? but the affect on a 1mm card or veneer can be quite significant ,
i use pva on my small card and veneer panels and have experimented with epoxy ,to give the panels a bit of body .
they flap around too much without this coating, egg whites might be another option ? especially if it has a reduced weight when dry ?
i have just finished another packet of cereal, the box is 19cm x30cm this seems a good size to start with.
i think i will glue the two .5mm together with pva as usual as the egg whites will probably just soak away into the panel.
so i will end up with a 1mm x 19cmx30cm panel with pva in the middle and an egg whites coating.
i may do some tests with a scrap piece first and see how it goes.
steve.
Steve and Christian I would like to get your opinion on this material. Thank you .... long time reader getting ready to pull the trigger on building a few panels 
https://www.lowes.com/pd/Hillman-24-in-x-36-in-Blank-Sign/3340838
oh and greets from across the pond... Just a little to the north
https://www.lowes.com/pd/Hillman-24-in-x-36-in-Blank-Sign/3340838oh and greets from across the pond... Just a little to the north
Alaska129.
Greetings.
The panel seems a little too thin at 0.2 inches ? For a 12inchx36inch panel , unless you intend to cut it into smaller panels ?
The price also seems a little expensive, plus postage ? ( I'm as tight as a ducks *@#%).😃
I have not used this material ? and others have mentioned problems with similar panels.
So it is a bit of a risk , hopefully someone else will have the answer ?
Steve.
Greetings.
The panel seems a little too thin at 0.2 inches ? For a 12inchx36inch panel , unless you intend to cut it into smaller panels ?
The price also seems a little expensive, plus postage ? ( I'm as tight as a ducks *@#%).😃
I have not used this material ? and others have mentioned problems with similar panels.
So it is a bit of a risk , hopefully someone else will have the answer ?
Steve.
Hello Alaska129Steve and Christian I would like to get your opinion on this material. Thank you .... long time reader getting ready to pull the trigger on building a few panels
oh and greets from across the pond... Just a little to the north
I have no experience with sheet of plastic. When I had a look to this kind of material I remember finding mainly polypropylene with the question of gluing Steve reported.
@spedge : are there common points with the proplex you are testing?
Christian
Christian.
I'm not really testing anything, I'm just showing the common sound I suppose ?
The only reason I started making small panels was because some people were saying they couldn't work !
I surprised myself by not only proving they work , but they can sound just as good 👍
obviously in the recordings the proplex is full range and the small panels use low frequency drivsrs.
Steve.
I'm not really testing anything, I'm just showing the common sound I suppose ?
The only reason I started making small panels was because some people were saying they couldn't work !
I surprised myself by not only proving they work , but they can sound just as good 👍
obviously in the recordings the proplex is full range and the small panels use low frequency drivsrs.
Steve.
Steve:
I have not gotten any materials or exciters yet. While I’ve read this form start to finish at least twice, along with all the you tube posts I could find. BTW I’m guessing those are your canvas art panels on You Tube ? And found Christians pdf studies very informative. I’d love to try BurnCoils version of the London Panels 3mm Birch but sadly Baltic Birch is not available right now. The 60 x 60 x 2.54cm XPS that Parts Express did and used your pva coating on is one option. Although I agree with your comments about using a stiffer coating like the epoxy you used on the thinner 5 mil panel. I was thinking water born Polly Urethane? Plexiglass or revolution plywood that Veleric used are also options. Sizes 60.96 x 121.92, 60.96 x 76.2 on down are all options. Full range with a 200 Hz High Pass and small sub ? Probably Dayton exciters. Wondering how( Formica) Countertop laminate might sound ?
Sorry this is long and thank you for your help and input
Pete
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