Suggest use the supplied sticky film to start with but with this modification which has worked well for me -
Apply 50mm/65mm wide (or thereabouts) masking tape (painters paper tape-Scotch/Duck/Frog/Bear etc) to the plywood in the selected location - make the tape long enough to protrude about 30mm or so beyond both edges of the exciter (so you can get a peel-off edge started later) . Press down firmly and rub with fingers. There are different release grades of these tapes - avoid the blue ones - the standard cheap beige tape works fine.
2/ Now stick the exciter to the tape. If you're happy with the result, peel the tape off the ply - it'll be stuck quite firmly at the exciter but will come off OK.
3/ Peel the tape from the exciter- remove the sticky stuff from the exciter and glue to ply with a thin layer of epoxy or PVA (not sure of PVA long term - I use a different styrene based glue mentioned previously).
If you want to try different locations - redo the tape process but remove the original sticky film (now in a used state) from the exciter and glue the exciter to the tape with either contact glue or PVA. Wait until dry and test . Repeat as necessary. If you don't overdo the glue, no need to remove from exciter each time - just apply another thin layer - when finalised, remove glue layer with fingernails - it'll peel off ok. Clean exciter mounting surface with alcohol/methylated spirits or similar if desired - probably not necessary but...
I've tested extensively and found that the very thin paper tape has no effect on the frequency response.
Eucy
These plots in this post 5642 clearly show what will happen when tape is used to stick the exciter onto a panel.
Which is fine for testing, not that I can probably hear this high a response.
Reaching 20k is not unusual, when the exciter is firmly glued to the panel.
The hump at 10k is easily solved as are the dips before and after this 10k point.
I have also seen the 2k and 3k hump changing with microphone position, with distance it disappears into the pink noise.
Steve.
Just a thought, has anyone tried an oversized frame and fasten the material/panel to it completely around, then coat with desired treatment, both sides or whatever and allow to completely dry, then cut out the size you were going for from said frame? Seems like that would go a long way in "warpage" management.
I think if the panel is stiff enough to be a good candidate for a DML panel it will not be an issue. At least with EPS I did try a generous double layer of hide glue on a 10mm panel and it didn't warp. I did when I added shellac to one side however.
Hello,
I am not sure there is a link between the desired stiffness for DML and a natural resistance to warping. It depens a lot on the way the material will absorb the solvent and changes locally. The examples I have in mind are "thin" (ie 3mm) plywood, cardboard (if still used).
As the coating which also gives the final aspect, it seems not easy to cut after.
The error i made on my plywood panel was to apply the varnish on only the front face in a first time and in a second on the back side.
In a previous post, Spedge gave the trick to heat the PVA locally as it is applied on cardboard to make it dries very fast.
So a frame to apply coating on both side at same time seems a good but in my opinion on the final dimensions. On the back side, the area dedicated to the suspension might be not covered.
Some ideas are needed to keep the panel on the frame for this operation; Temporary double side tape?
Christian
Maybe some very thin ply will warp with hide glue, but I doubt it will be an issue. Most ply should be at least as stiff as a 10mm EPS I would think, even if it will react a bit differently to the moisture in the glue. Probably thin cardboard will warp, but not sure if that would be considered a good candidate for a panel?
New tech that could be interesting for DML panels:
http://www.sci-news.com/othersciences/materials/2dpa-1-polymer-10518.html
http://www.sci-news.com/othersciences/materials/2dpa-1-polymer-10518.html
Leob.
I'm probably not going to hold my breath waiting for that new product to come on the market at a reasonable price.
But it was interesting.
I went mad as usual and pulled a packing grade eps out of a grundon , (big rubbish bin) it is about 2ft square and 25mm thick .
The surface is quite soft but does not have any holes in its surface.
I have been meaning to test the frequency response and sound of a soft 1inch eps panel , to compare to my 70grade 1inch eps.
As every one knows ,I hope, I like the sound of eps, but what is the advantage of higher eps grades ,if any ?
Will I be able to extract a good hf response ?
Will this material be too thick and soft ?
Only one way to find out.
I did do a review of the protex panel sound before the weekend but lost it all when I uploaded it , as the site said oops something went wrong !!! .
Oh well.
Steve.
I'm probably not going to hold my breath waiting for that new product to come on the market at a reasonable price.
But it was interesting.
I went mad as usual and pulled a packing grade eps out of a grundon , (big rubbish bin) it is about 2ft square and 25mm thick .
The surface is quite soft but does not have any holes in its surface.
I have been meaning to test the frequency response and sound of a soft 1inch eps panel , to compare to my 70grade 1inch eps.
As every one knows ,I hope, I like the sound of eps, but what is the advantage of higher eps grades ,if any ?
Will I be able to extract a good hf response ?
Will this material be too thick and soft ?
Only one way to find out.
I did do a review of the protex panel sound before the weekend but lost it all when I uploaded it , as the site said oops something went wrong !!! .
Oh well.
Steve.
JohnnoG.
I have been gluing and listening to the eps and the thin protec panels.
I had to turn the eps down about 13db to match the thicker protec panel and about 9db for the thinner protec panel.
Firmly gluing also stopped the hf drop off above 10k and smoothed out some blips.
I am now waiting for the second thin protec panel to dry so that I can have an almost matching pair( I have offset the exciter on the second protec panel to see if there is any change in response ? )
4mm Correx seems more available in small quantities in the UK, which is supposed to be the same thing?
Steve.
I have been gluing and listening to the eps and the thin protec panels.
I had to turn the eps down about 13db to match the thicker protec panel and about 9db for the thinner protec panel.
Firmly gluing also stopped the hf drop off above 10k and smoothed out some blips.
I am now waiting for the second thin protec panel to dry so that I can have an almost matching pair( I have offset the exciter on the second protec panel to see if there is any change in response ? )
4mm Correx seems more available in small quantities in the UK, which is supposed to be the same thing?
Steve.
JohnnoG.
It would be interesting to find out how large a panel ,is too large ?
What is the optimum size for this material, using one exciter ?
The hi frequencies above 10k are pretty much within a small area maybe spreading 6inches from the exciter(at a guess ?).
So the rest of the 60x60cm proplex is mainly radiating up to about 10k.
You will also, with a very large panel start to get large panel resonances, which can ,maybe , be reduced with panel shape ?
Steve.
It would be interesting to find out how large a panel ,is too large ?
What is the optimum size for this material, using one exciter ?
The hi frequencies above 10k are pretty much within a small area maybe spreading 6inches from the exciter(at a guess ?).
So the rest of the 60x60cm proplex is mainly radiating up to about 10k.
You will also, with a very large panel start to get large panel resonances, which can ,maybe , be reduced with panel shape ?
Steve.
JoohnnoG.
Flutes.
I have just done a quick test of the response across and down the flutes .
Across the flutes the hf drops after a few inches.
Along the flutes the hf holds up better.
But something I did notice was that the hf along the flutes increased when moving the microphone away from the surface.
I traced this to beaming above 10k from the exciter area ?
This did not happen across the flutes?
So if the panel is close to a wall I would recommend the flutes are pointing downwards, to stop the wall reflection, if it is a problem?
I had similar problems with an eps panel I have.
Interesting.
Steve.
Flutes.
I have just done a quick test of the response across and down the flutes .
Across the flutes the hf drops after a few inches.
Along the flutes the hf holds up better.
But something I did notice was that the hf along the flutes increased when moving the microphone away from the surface.
I traced this to beaming above 10k from the exciter area ?
This did not happen across the flutes?
So if the panel is close to a wall I would recommend the flutes are pointing downwards, to stop the wall reflection, if it is a problem?
I had similar problems with an eps panel I have.
Interesting.
Steve.
Hi Steve
I am bit 'thwackered' from the effects of a six hour round Vehicle Journey, I might sound a little garbled with my replies.
The initial Panel Dimension will be required to fit not too intrusively into the Temporary accommodation, the dimension will be decided nearer the time of downsize having happened. As said previously, a simplistic SS State system can be used, even my Son's Old Denon Integrated Amp with a DAC and Laptop with FLAC Files will be plenty for Music, The TV can also be put through this when watching a Movie.
I am hoping that the Exciter Selected for this Panel will be the ideal one to take onto another stage of DML later.
My wife will remain committed to her use of Alexia, so that is the entertainment sorted to a degree.
On returning into the home ' to commence decorating' which will be, if all the planets align, be very late 2022, but most likely the early months of 2023. With this in mind the Panels to be used are a way of, along with the dimensions to be selected.
I do think a Parking Bay and Cantilever TV Wall Bracket as previously suggested will be a good method for the Home Entertainment/TV Space, so a Dimension will be required for the producing a Parking Bay when decorating.
On paper I have a dedicated listening space in the home, but I also have a lot of construction materials and have toyed with having a External Entertainment Space, that could easily be a with a partitioned of secure home for the HiFi System, and then either leaving the Speaker permanently on display or have them on a Plinth that can be wheeled into the security of the partitioned off area.
Having the Valve Equipment in a space 'not attached' to the home, seems to be a tonic to my thoughts, I have been ritualistic for nearly 30 Years with discipline for using Valves.
The budget due to many owned materials will allow for a external structure, but the prettying up, might be a long haul.
A Long winded way off saying the Panel Sizes are to be determined to be used with the HiFi System when reassembled.
A friend is making it known they intend on visiting a HiFi Show in Daventry later in the year, they usually drive a VW Mini Bus, this might be a good time if you wish to intercept the bus to pick up a Larger Panel Dimension, or I might be able to encourage a drop off, with Full Size Sheets to enable further experimentation.
I hope the above is not too garbled.
I am bit 'thwackered' from the effects of a six hour round Vehicle Journey, I might sound a little garbled with my replies.
The initial Panel Dimension will be required to fit not too intrusively into the Temporary accommodation, the dimension will be decided nearer the time of downsize having happened. As said previously, a simplistic SS State system can be used, even my Son's Old Denon Integrated Amp with a DAC and Laptop with FLAC Files will be plenty for Music, The TV can also be put through this when watching a Movie.
I am hoping that the Exciter Selected for this Panel will be the ideal one to take onto another stage of DML later.
My wife will remain committed to her use of Alexia, so that is the entertainment sorted to a degree.
On returning into the home ' to commence decorating' which will be, if all the planets align, be very late 2022, but most likely the early months of 2023. With this in mind the Panels to be used are a way of, along with the dimensions to be selected.
I do think a Parking Bay and Cantilever TV Wall Bracket as previously suggested will be a good method for the Home Entertainment/TV Space, so a Dimension will be required for the producing a Parking Bay when decorating.
On paper I have a dedicated listening space in the home, but I also have a lot of construction materials and have toyed with having a External Entertainment Space, that could easily be a with a partitioned of secure home for the HiFi System, and then either leaving the Speaker permanently on display or have them on a Plinth that can be wheeled into the security of the partitioned off area.
Having the Valve Equipment in a space 'not attached' to the home, seems to be a tonic to my thoughts, I have been ritualistic for nearly 30 Years with discipline for using Valves.
The budget due to many owned materials will allow for a external structure, but the prettying up, might be a long haul.
A Long winded way off saying the Panel Sizes are to be determined to be used with the HiFi System when reassembled.
A friend is making it known they intend on visiting a HiFi Show in Daventry later in the year, they usually drive a VW Mini Bus, this might be a good time if you wish to intercept the bus to pick up a Larger Panel Dimension, or I might be able to encourage a drop off, with Full Size Sheets to enable further experimentation.
I hope the above is not too garbled.
Hello Steve
Good question to ask if there is an optimum size... Considering the HF absorption it makes sense to think there is a dimension above which the level in HF will be not sufficient compare to lower frequencies.
Interesting also to see in such a material, the propagation is not the same in both direction.
Christian