It is myself who passed onto @spedge the round fluted Panel Material, that has made a good impression.
I have 8' x 4' Panels in this same material reserved for Steve, to pass on at a time when I visit him to hear samples of his work to date.
It is a shame the Round Fluted Panel is not more widely available to be tried out.
From my own end and after experiencing in use Densified Wood materials with inherent excellent damping/dissipation properties, I have become an advocate of this material type, and find a place to suggest it is used on a regular basis. To date such suggestions made have been maintained over what was in place prior to the exchange of materials.
A rosette produced to a few mm thickness and used as a separator from the Panel to mount the Exciter onto, 'might' bring an improved control of early produced energies, if the transferral of early produced energies, passes through a Rosette Material made from a Densified Wood such as Panzerholz and Permali.
If substantial damping is the only desirable mounting for a Exciter, the material Newplast Modellers Putty is exceptional for this purpose, about 3 x improved in recorded measurements for damping properties over a Plasticine Putty that has had Damping Properties measured.
I have 8' x 4' Panels in this same material reserved for Steve, to pass on at a time when I visit him to hear samples of his work to date.
It is a shame the Round Fluted Panel is not more widely available to be tried out.
From my own end and after experiencing in use Densified Wood materials with inherent excellent damping/dissipation properties, I have become an advocate of this material type, and find a place to suggest it is used on a regular basis. To date such suggestions made have been maintained over what was in place prior to the exchange of materials.
A rosette produced to a few mm thickness and used as a separator from the Panel to mount the Exciter onto, 'might' bring an improved control of early produced energies, if the transferral of early produced energies, passes through a Rosette Material made from a Densified Wood such as Panzerholz and Permali.
If substantial damping is the only desirable mounting for a Exciter, the material Newplast Modellers Putty is exceptional for this purpose, about 3 x improved in recorded measurements for damping properties over a Plasticine Putty that has had Damping Properties measured.
JohnnoG,
I'm not so sure damping is good for mounting an exciter, although I have never tried it. I do think damping is good for mounting a panel to a frame. I may have to try out the Newplast.
Thanks,
Eric
Can you remind me anything else you recall about the details of this material? What it is the brand or material, thickness, etc? Is there any way to source it other than from you?
Thanks,
Eric
Here is a extract I found in an old thread post, sent by a Guy who measured the Damping / Dissipation in a large qty of materials.
Choice of damping materials is limited. Epoxy goo, on its own is a poor damper, even with glass fibre (DF=~0.013) and carbon fibre (DF=0.02 to 0.06) it is next to useless. My recommendation is to use a Plasticine TM type material. This has a damping factor of 0.30, and I would recommend a brand called 'Newplast' TM which is even better at damping (DF=0.635) which compares very well with polyester resin/kitty litter (DF=0.618). The Newplast TM is cheap and readily available from art shops. Squeeze as much as you can 'twixt top plate and plinth. Also, it has the advantage of being reversible.
Choice of damping materials is limited. Epoxy goo, on its own is a poor damper, even with glass fibre (DF=~0.013) and carbon fibre (DF=0.02 to 0.06) it is next to useless. My recommendation is to use a Plasticine TM type material. This has a damping factor of 0.30, and I would recommend a brand called 'Newplast' TM which is even better at damping (DF=0.635) which compares very well with polyester resin/kitty litter (DF=0.618). The Newplast TM is cheap and readily available from art shops. Squeeze as much as you can 'twixt top plate and plinth. Also, it has the advantage of being reversible.
The Round Flute is a Sheet Material used as a Temporary Measure as a High Impact Floor Protection.
It is typically found as a 6mm Thick Material in sheets 8' x 4'.
The Material in the Link is the Product, it can be seen in the print on the board the construction is with round holes.
https://protection.co.uk/product/impactboardfr/
It is typically found as a 6mm Thick Material in sheets 8' x 4'.
The Material in the Link is the Product, it can be seen in the print on the board the construction is with round holes.
https://protection.co.uk/product/impactboardfr/
The Link is a USA source.
They supply a 1200 Grade at 5mm Thickness and 2500 Grade at 6mm Thickness.
https://entrypointusa.com/product/impactboard-fr-2500/
They supply a 1200 Grade at 5mm Thickness and 2500 Grade at 6mm Thickness.
https://entrypointusa.com/product/impactboard-fr-2500/
I'm out of action for a while folks.
Located just north of Brisbane and tropical cyclone Alfred has wrecked the area over the past few days
Today we've had about 300mm of rain, winds up to 150 km/hr in other areas, not near me.
Power is out for about 300,000 people including us.
Still raining, generator still running.
Life goes on.
Minor matters really, compared to other areas in this troubled world
Regards
Euc
Located just north of Brisbane and tropical cyclone Alfred has wrecked the area over the past few days
Today we've had about 300mm of rain, winds up to 150 km/hr in other areas, not near me.
Power is out for about 300,000 people including us.
Still raining, generator still running.
Life goes on.
Minor matters really, compared to other areas in this troubled world
Regards
Euc
JohnnoG,
If you can share a link to that post I'd be interested to read it. I did a quick search of this forum but didn't find it. Was it here on DIYAudio, or somewhere else?
Thanks,
Eric
Lenco Heaven is the place where the discussions about materials and their intrinsic properties has been aired publicly for many years.
Materials such as Panzerholz may well have been introduced for audio use in the forum.
Bryan has received uncommon materials from myself and measured them to allow for me to see where they fitted in around more commonly available materials.
In all things conceptual, those who attack change / Flat Earthers are in the Flanks waiting their chance to condemn the alternate concepts, Bryan was subject to a reasonable dose of the challenging ways of a small group of others.
Until Proven wrong, I have him as the individual who turned the Little Acorn Concept of Densified Wood into the Mighty Oak it is today.
Along with other Audio Brands and a multitude of Build Your Own enthusiasts, Linn are now onboard with their $8K Bedrok Densified Wood Plinth.
The Link is to all Posts by ZM1080 who is also known as Catsquirrel, real name Bryan
https://www.lencoheaven.net/forum/index.php?action=profile;u=8161;sa=showPosts;start=0
Materials such as Panzerholz may well have been introduced for audio use in the forum.
Bryan has received uncommon materials from myself and measured them to allow for me to see where they fitted in around more commonly available materials.
In all things conceptual, those who attack change / Flat Earthers are in the Flanks waiting their chance to condemn the alternate concepts, Bryan was subject to a reasonable dose of the challenging ways of a small group of others.
Until Proven wrong, I have him as the individual who turned the Little Acorn Concept of Densified Wood into the Mighty Oak it is today.
Along with other Audio Brands and a multitude of Build Your Own enthusiasts, Linn are now onboard with their $8K Bedrok Densified Wood Plinth.
The Link is to all Posts by ZM1080 who is also known as Catsquirrel, real name Bryan
https://www.lencoheaven.net/forum/index.php?action=profile;u=8161;sa=showPosts;start=0
I regularly also visit a machining forum and saw some similar comments from someone else in your part of the world.
Stay safe!
Thanks
450,000 households lost power
300,000 now restored
Not ours yet
Also flooding in a number of areas.
First time in 50 years that a tropical cyclone has tracked this far south.
Global warming has apparently increased sea temperatures and we can expect more in the future
Cheery stuff
Eucy😵💫
450,000 households lost power
300,000 now restored
Not ours yet
Also flooding in a number of areas.
First time in 50 years that a tropical cyclone has tracked this far south.
Global warming has apparently increased sea temperatures and we can expect more in the future
Cheery stuff
Eucy😵💫
I received a couple of XTB40-8's and some XT25's today, I didn't have much time to play with them but did a quick test on an HD Eps panel I had.
The panel is approx 12mm thick HD EPS 600/400mm, I had tuned it with a couple of weights for the XT32 I had on it. It is suspended in a frame with 30/3mm foam tape around 3/4 of the edge, corners free. Around a 5mm gap to the frame. I removed the weights when I added the XTB40.
The XTB40 definitely falls off above 1khz then very steeply from 7khz. There is good bass to mid 40's but not noticeably more than the XT32 on the same panel, it will be interesting to see if it can handle more power and play louder without strain once I run it with the dsp crossover. The panel needs some work as there is suspension noise when it's turned up very loud and the bass is more extreme.
Below are some quick dirty bench close mic measurements comparing XTB40 with the XT32. I didn't have time to try different positions but will in the future.
I also added the XT25 with a capacitor high pass near the edge to try them together, this is measured on the bench from 250mm. Second screenshot.
I think this could work quite well with a little tweaking and tuning.
The panel is approx 12mm thick HD EPS 600/400mm, I had tuned it with a couple of weights for the XT32 I had on it. It is suspended in a frame with 30/3mm foam tape around 3/4 of the edge, corners free. Around a 5mm gap to the frame. I removed the weights when I added the XTB40.
The XTB40 definitely falls off above 1khz then very steeply from 7khz. There is good bass to mid 40's but not noticeably more than the XT32 on the same panel, it will be interesting to see if it can handle more power and play louder without strain once I run it with the dsp crossover. The panel needs some work as there is suspension noise when it's turned up very loud and the bass is more extreme.
Below are some quick dirty bench close mic measurements comparing XTB40 with the XT32. I didn't have time to try different positions but will in the future.
I also added the XT25 with a capacitor high pass near the edge to try them together, this is measured on the bench from 250mm. Second screenshot.
I think this could work quite well with a little tweaking and tuning.
Attachments
Hi all. I lurked for a bit but so far I can't find answers to some questions I have.
I have a pair of 2' by 4' sheets of 1/4" plywood and 40w dayton exciters. It sounds okay but highs are lacking. I have a subwoofer on the way.
Are there any downsides to making panels this big? Space is not really a concern for me.
Will I get more accurate highs by making panels smaller?
What are the benefits to mounting the DML to a frame with double sided tape?
What has been all of your favorite-sounding setups?
I have a pair of 2' by 4' sheets of 1/4" plywood and 40w dayton exciters. It sounds okay but highs are lacking. I have a subwoofer on the way.
Are there any downsides to making panels this big? Space is not really a concern for me.
Will I get more accurate highs by making panels smaller?
What are the benefits to mounting the DML to a frame with double sided tape?
What has been all of your favorite-sounding setups?
Hi trenth,
Welcome.
Making a panel larger sometimes increases its range on the low side, but once you get to a certain size, making it any larger doesn't help, and may hurt. My own experience is that there is no benefit from having a 1/4" plywood panel any larger than about 2 sq ft. Something like 24x16 or so works pretty well, or even 12x48. But it does depend on the particular panel. You may have to experiment if you really want to know.
Making the panels smaller won't help the highs. Basically the highs are independent of the panel size.
There are two benefits of mounting the panel to a frame with double sided tape. First, it will boost the SPL in the low frequencies. Second it can provide enough damping to reduce or eliminate sharp resonance peaks, which (if not sufficiently damped) cause spikes in the SPL and ring for extended periods. A pretty good tape that's readily available in the US is 3M Extreme outdoor mounting tape, which you can get in any Lowe's or Home Depot.
These are my experiences, and not all here will agree.
Eric
Welcome.
Making a panel larger sometimes increases its range on the low side, but once you get to a certain size, making it any larger doesn't help, and may hurt. My own experience is that there is no benefit from having a 1/4" plywood panel any larger than about 2 sq ft. Something like 24x16 or so works pretty well, or even 12x48. But it does depend on the particular panel. You may have to experiment if you really want to know.
Making the panels smaller won't help the highs. Basically the highs are independent of the panel size.
There are two benefits of mounting the panel to a frame with double sided tape. First, it will boost the SPL in the low frequencies. Second it can provide enough damping to reduce or eliminate sharp resonance peaks, which (if not sufficiently damped) cause spikes in the SPL and ring for extended periods. A pretty good tape that's readily available in the US is 3M Extreme outdoor mounting tape, which you can get in any Lowe's or Home Depot.
These are my experiences, and not all here will agree.
Eric
Thanks. For highs, I will use a second set of maybe 25w exciters and smaller panels in parallel or something.
What materials have you found result in good highs? I want to make a two material hybrid setup that covers the largest possible range.
Also, I built a frame around my big plywood sheet and mounted with tape like you said and HOLY COW does it sound louder, more efficient, more balanced, ELIMINATED buzzes and bad resonance I was getting. Night and day difference compared to a regular plywood sheet in the same configuration.
Also, this is old news but I also saw a marked improvement in flatness across the frequency response when placed about two feet from the wall rather than right on the wall. Being only a few inches from the wall gave the worst results.
What materials have you found result in good highs? I want to make a two material hybrid setup that covers the largest possible range.
Also, I built a frame around my big plywood sheet and mounted with tape like you said and HOLY COW does it sound louder, more efficient, more balanced, ELIMINATED buzzes and bad resonance I was getting. Night and day difference compared to a regular plywood sheet in the same configuration.
Also, this is old news but I also saw a marked improvement in flatness across the frequency response when placed about two feet from the wall rather than right on the wall. Being only a few inches from the wall gave the worst results.
I'm glad that worked for you. Did you stick with the full size 2x4, or cut it smaller? Also, did you use the 3M Extreme tape or something different? Just curious.
As far as the highs I can't really suggest anything in particular. Maybe someone else can.
Eric
Hello,
More than speaking in power, I would say with an exciter having a 25mm voice coil (so yes more in the 10 to 25W range) rather than a 32mm (40W range), you should get better highs.
And (not or, both needed in my current understanding) )for the material, my suggestion would be to test thinner and maybe lighter plywood (I don't know the wood you have currently). Poplar or basswood in 3 or even 2mm. In my opinion thin plywood can't be used without a frame because of warping problem.
Plywood is probably not the only choice but it should lead to not too bad results with a material not too difficult to source, with about the same characteristics in our different locations.
I have no experience with "thick" plywood (1/4" = 6.35mm). I had a sample of 5mm standard (french) plywood in the directivity tests some weeks ago. I won't recommend it to go high. Its directivity characteristics were not good (high SPL out of axis at high frequency).
Of course this is more opinion despite we have some interesting measurements than coming from strong and stable design rules.
Christian
As this thread is so long.
Who has an overview?
Which material is considered good or best for a DML panel?
Who has an overview?
Which material is considered good or best for a DML panel?
Oh dear
What can be said?
Reading glasses on.
Long nights ahead.
Best of luck.
Christian's GitHub page is a good start.