Sounds like you tried The Foam Company like i did , "minimum order size $ 200 Sir" , They claimed Clarke Rubber carry their 10 mm thick sheets of 24 kg/3M EPS but upon asking them Clarke say "nope . never seen one"
Most Bunnings stores have 10 , 15 , 20 , 25 mm EPS Foilboard but based on their claimed mass of 1.46 kg per 25 mm sheet , the density would be 20.27 kg/3M and you still have to peel off the green plastic moisture barrier assuming you can find a sheet that hasnt been dinged dented or had forklift tynes driven through it by the average employee - of - the - month
You would have to try it and probably other thickness combinations. Much to my surprise XPS is around down to 6mm, Foam backed panels have been used commercially in the past but in an entirely different way. Panel effectively in a shallow cabinet filled with foam. That needs a different type of foam. It absorbs sound and could also provide some panel damping depending on how much it's compressed etc and the type of foam, There is more recent talk about air springs ; details of what that means in practice are scant.
There are some decent videos of a few different panel materials on this channel. The poster has got a bit fed up with posting on here
https://www.youtube.com/@sedge3813/videos
As one of the videos shows plenty of panels have been built - some have been videoed. Sound - well to some extent that will relate to what people listen with.
I am sure I have seen comments about paper coated EPS panels being used.
500 pages does look tired and unfocused
DML should be able to classify several new topics
Board size, board material, board shape, board support style, various differences in drivers on the base board...etc
These can be divided into many types
so that there will be no unfocused discussions
I think there should be a veteran out to take the lead in formulating a new classification topic
True , regarding the volume for any newbies to trawl through .
Anyone attempting to read through 10,000 posts is going to get overloaded with black internet ink on the left brain hemisphere and it could cause a shift in the earths polar alignment.
The problem with breaking it down in to individual threads on topic is there is too much crossover between material type , construction and function , best we could hope for is to maintain this thread while having a new thread with categories that this thread link a copy to , and maybe if we are in an IT kingdom where magic can prevail we could have posts in the reference thread that are moved to the top of thread based on a readers vote for winning / breakthrough / most popular performance.
Anyone attempting to read through 10,000 posts is going to get overloaded with black internet ink on the left brain hemisphere and it could cause a shift in the earths polar alignment.
The problem with breaking it down in to individual threads on topic is there is too much crossover between material type , construction and function , best we could hope for is to maintain this thread while having a new thread with categories that this thread link a copy to , and maybe if we are in an IT kingdom where magic can prevail we could have posts in the reference thread that are moved to the top of thread based on a readers vote for winning / breakthrough / most popular performance.
That is another one I have considered... I have a large roll of matte vellum drafting paper that would make for a nice face material. It would also look a lot nicer than pink foam.
I have not tried any of the foams (XPS and EPS), and many people have talked about using a dampening backing so that the only sound they hear is from the front (boxes, Foam, pillow stuffing, etc). This just occurred to me. What if, when making small panels, you were to put several panels of the same size behind those panels in an enclosure, each one slightly separated, or maybe not separated? Maybe coat all the panels with the PVA mixture. You would have plenty of left-over foam to do this. I don't know if this would produce ringing. Just a thought.
i suspect one reason for sanding and coating foams with dilute PVA is that it will help coating them with any colour of water based emulsion paint you might like to use.
Pink foam can be painted and even routed, and the paint helps some with the bad spectral decay getting discussed.
In the semi-near future I still have my first pink foam with frame, my test frame, it's deep enough I can put a back on it and fill it with the other pink stuff -- fiber glass insulation. I contacted Dayton and one of the engineers explained they test in a anechoic chamber with the foam mounted over a hole in the wall so the back bleeds into another room. God bless Spedge, his criticism of my original deployment idea was more true than I appreciated until I tried my tower panels in the middle of the room. They sounded like big, deep speakers, even without sub support (with acoustic music). At that point, the frame, plus paint, plus away from reflective surfaces and back shooting into a jagged oblivion as much as possible (10 foot ceilings plus shelves and random stuff everywhere); I highly doubt spectral decay is the foremost significant issue with getting to the next level of sound quality.
Really, the next step is benchmarking. I have a decent pair of floor-standing speakers and some okay studio monitors, and I need to do a showdown. But what I really want is to acquire some magnepans and test them against other panels. The thing is, the scale factor with DML is mind-boggling, even if a 1k$ pair of magenpans win, it's about 45$ a panel including paint to build a module. Right now I have 2 stacked, but they simply bolt together and another 180$ gives me 2 4x panels. So for 720$ (and my time) I could have 2 4ft by 8ft panels that weigh about nothing, are the maggies going to sound bigger than that?
LOL More on pink and blue. I'm only interested in what I can easily buy which may mean Amazon. It appears the difference is largely the maker. Density for insulation board >30kg. some din standard. XPS may go by the name of styrofoam. Then there is EVA - pass on that but glue may melt it. People have used fluted corex. Acrylic, ply, light ply, balsa even balsa coated. A kickstarter project used carbon fibre, failed to get enough backing to continue. I'm currious about PVC foam.
Actually I bought some used PC speakers that use small oblong corex board with the fluting running along the long length. The panels are rigidly mounted and I can't help wondering if their lower frequency range can be extended by using different materials and suspensions. The panels are ~A5 sized.
Actually I bought some used PC speakers that use small oblong corex board with the fluting running along the long length. The panels are rigidly mounted and I can't help wondering if their lower frequency range can be extended by using different materials and suspensions. The panels are ~A5 sized.
I think a moderated Wiki is the way to go. There is plenty of information in this thread and in some of the tangent threads to create a good outline and fill in much of that outline. I do not think the problem is the volume of information here, but the almost inherently scattered and disorganized nature of that information.True , regarding the volume for any newbies to trawl through .
Anyone attempting to read through 10,000 posts is going to get overloaded with black internet ink on the left brain hemisphere and it could cause a shift in the earths polar alignment.
The problem with breaking it down in to individual threads on topic is there is too much crossover between material type
Right now about the only way to keep it straight is to find a builder that has produced results you like and read through their posts specifically, like Spedge, Veleric, BurntCoil, et. al..
I am tempted to start a Wiki; I have written many technical papers in the past (part of being an R&D engineer), and have built countless speaker systems over decades of multiple alignments, but in all modesty I am comparatively very new to DML.
@spedge made some DMLs from this material. It is in one of his youtube videos. In the States it is also referred to as coroplast and is handy stuff since it is cheap and light and easy to find (sign shops) in 4' x 8' sheets; I have used it to build race car radiator ducting for example for which it works well.
I think you could achieve the same thing more easily with some Corning 703 rigid board insulation. It's the go-to for acoustic damping material. acoustic ceiling tiles would be another option. One of the DML patents somewhere talks about damping via acoustic coupling to a material behind the sound panel.
While I don't disagree at all, what I was getting at was using the left-over XPS or EPS like a series of DMLs behind the one with the exciter mounted on it.
sorry about that; probably the most important aspect of the proposed wiki will be to get sourcing options for available materials known to work well across the globe. Once you can get decent material, it's 2 minutes of education to achieve 80% plus of the sound quality you'll likely ever be able to achieve with that panel.
I've never tried (or even seen) R-Max before, but based on the description I found on the Home Depot site, it is not EPS (nor XPS) but rather "Polyiso(cyanurate)". See here the datasheet from the manufacturer. I'm not saying it's good or bad, just that it appears not to be EPS.
I do think there might be some potential for a wood/foam/wood sandwich. I have tried it myself at least once. It wasn't great but that could have been more due to my poor excecution rather than the idea itself. But a sandwich as thick as you are proposing would be way too stiff. If you want to try something like that, I would suggest something more like a 3 to 5 mm foam core with 0.5 mm veneer for skins.
I think you should give the 1/2" XPS (foamular) a shot. Not because I think it's so great, but rather because it's really cheap and anybody who's investigating DML's needs to have tried EPS and/or XPS at least once. It's like a rite of passage. The difference in efficiency between PS foam (either type) and almost any other common panel material is so huge. You need to hear what "crazy-efficient" PS foam sounds like to put every thing else into perspective. The 1/2" foamular in my area comes with a plastic skin on both sides that I normally peel off. But you can tried it with and without if you like.
I'm suggesting XPS (Foamular) over EPS only because I know you can get it easily at Home Depot. Decent EPS is much harder to find in the US, at least in my area/experience. I think HD (or Lowes) carries some, but it was very low density and very soft and not close to what (I think) people have reported good succss with.
Eric