Posible panel material
Not sure if this is of intrest but may be worth a try, cheap and available on line in the uk 2400 x 1200 size
ThermHex - Made from a Polypropylene Honeycomb Core
Steve
Not sure if this is of intrest but may be worth a try, cheap and available on line in the uk 2400 x 1200 size
ThermHex - Made from a Polypropylene Honeycomb Core
Steve
JMC panels cost $6.5k for a single panel if I am not mistaken.
Plywood is not a good material because its layers of wood with glue between each layer so it becomes stronger but it also becomes heavy and over damped.
Like I said before the best panel material is a material that is very light. Three characteristics of a good material are.
1. Needs to be very light- Lighter the material means its more efficient.
2. Needs to be very stiff/dense- stiffer/denser the panel means more Accuracy and clarity.
3. At the same time it needs to have a slight degree of flex as the vibrations need to bend the panel to a small degree. With most materials the THINNER the material the more it bends. Go and watch Tech ingredients first video. The material with the best bass is the aluminum panel for the mere fact that it is the THINNEST of all the panels there for its able to flex more increasing bass output. Also the bass output is cleaner and more accurate when using thinner panels. Thicker panels bass is more muddy.
EPS/XPS and Honeycomb composite meet those 3 criteria which is why they are the best most preferred materials.
Best tone is wood as a lot of people prefer wood tones. Problem is most wood pound for pound are on the heavier side, when compared to EPS/XPS.
Lightest wood I have found is Balsa the ones used for crafts and hobby. Even though it is light its still heavy so you will need a very thin piece of balsa wood say around 1/8-1/16 thick. Only down fall is that this wood is not readily available and the largest width I have found does not go over 12inchs and most panels to have adequate bass needs to be a minimum of 16inches width. The ones in my local hardware store are only 4inches in width which is too thin for bass response. It can be used as satellite panels but you will definitely need a powered subwoofer to fill in the lows.
Adding anything to a already heavier material will just make it more heavier which means less efficient. So its best to start off with the lightest material possible then add things on. Oh I forgot to add that you can use some type of wood fiber for skin on EPS/XPS material but it has to be very thin because too thick will lose efficiency.
The ribs just keep the panels curved shape. I want to ask them there reasoning for there curved shape and if it actually makes a difference in sound or if its just for cosmetic purposes or both.
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So far I tried 3mm hardboard, a Formica sheet of about 2mm and an Armstrong Dune ceiling tile and I can tell you that the ceiling tile has the best sound by some considerable margin. The Formica was so bad I took the exciter off immediately upon first listen.
I’ll experiment with the ceiling tiles for awhile longer.
My suggestion would be to forget about trying to go full range and roll your panels off below
100Hz or so and fill in with a sub.
I’ll experiment with the ceiling tiles for awhile longer.
My suggestion would be to forget about trying to go full range and roll your panels off below
100Hz or so and fill in with a sub.
This question may be too general in nature but, if one were to use a composite panel consisting of a lighter (less dense) material on one side and a more dense (stiffer) material on the other, which side would be better for mounting the exciter or would it not matter due to the operating principles behind DMLs?
Its not a question of density per se. Its a question of compression strength. A high compression strength allows the waves to transfer much easier through the material and creates greater panel efficiency (higher SPL's) and also allows the easier transfer of HF's (The higher the compressive strength the better the HF).
Think of it this way, foam rubber can be very dense, yet its compression strength is very low (i.e., you can easily squeeze the material a great deal between your fingers). So what you want is material than doesnt squeeze easily...greater compression strength.
So since the objective is to at leaast get as much signal into the panel as possible, then the higher compression strength would probably best be put on the excitor side. And if the other side is of lower compression strength, then you probably will want the exciter to be on the front of the panel rather than the rear...Just my thoughts without any imperical proof...experiment and let us know what you find
I always appreciate this kind of info! I would like to suggest though that to make the data more complete and useful we provide the following:
1. Panel material (including brand, cost and maybe a link to where you got it)
2. Shape of panel
3. Size of panel
4. Thickness of panel
5. Weight of panel
6. Compressive Strength of panel (if known)
7. Transducer/Exciter used for test
8. Mounting of panel (free, framed, hanging)
9. Location tested (how far away from wall, wall mounted, maybe approximate room size)
10. Test equipment used (mic, phone, SPL meter, REW, ears, sound sources, music type, etc...)
11. How does it sound?
I know that sounds like a lot but it would definitely help to develop a database of what works and what doesn't. Otherwise we will simply have another 10 year old thread in which to try to find answers thast have probably been already answered and buried in history. With all the decades of trial and error experimenting people have done in all the various forum threads on DIY DML's it would be nice to be able to collate the data for much easier usage and dissemination.
I always appreciate this kind of info! I would like to suggest though that to make the data more complete and useful we provide the following:
1. Panel material (including brand, cost and maybe a link to where you got it)
2. Shape of panel
3. Size of panel
4. Thickness of panel
5. Weight of panel
6. Compressive Strength of panel (if known)
7. Transducer/Exciter used for test
8. Mounting of panel (free, framed, hanging)
9. Location tested (how far away from wall, wall mounted, maybe approximate room size)
10. Test equipment used (mic, phone, SPL meter, REW, ears, sound sources, music type, etc...)
11. How does it sound?
I know that sounds like a lot but it would definitely help to develop a database of what works and what doesn't. Otherwise we will simply have another 10 year old thread in which to try to find answers thast have probably been already answered and buried in history. With all the decades of trial and error experimenting people have done in all the various forum threads on DIY DML's it would be nice to be able to collate the data for much easier usage and dissemination.
How does one know what works and what doesn't? The only thing that actually matters is #11. How does it sound? Compared to what?
Most have never heard a good quality sounding DML panel let alone build one.
I bet that's true.
It would be great if someone who had built a truly good sounding DML would share the plan.
Eric
They already have done this but not on this forum. Just search for ‘The worlds best speaker’
on YouTube and there is a 40 minute evaluation of many types of board materials, shapes and sizes with measurements and a listening session at the end. The most comprehensive study that I have seen. A ‘must watch’ if you are thinking of DML’s
on YouTube and there is a 40 minute evaluation of many types of board materials, shapes and sizes with measurements and a listening session at the end. The most comprehensive study that I have seen. A ‘must watch’ if you are thinking of DML’s
+1
I have been following this thread with great interest and making notes as I go along. I would also really like to hear good sounding DMLs firsthand one day. They look so easy to construct and almost too cheap to sound good. Being a rookie speaker builder I have made a few wonderful sounding Full Range speakers (Frugal Horns, TABAQs, mini Karlsonators) before, but that was from specific plans (exact dimensions, specific speaker drivers, stuffing recommendations, etc.) – and they even have names.
I have also watched the Youtube video (World’s best speakers) jerryo refers to a while ago, but they ended up with 8 panels (4 per channel), using a mix of exciters and 4 amplifiers to drive the lot – totally impractical (in terms of space) for me.
Eric, you look like you are on the road to building great sounding DMLs? You seem to have mastered MLTL designs before – maybe you can share a DML plan with us soon. And give it a name.
Yes, that would be nice if someone could give a detailed recipe or plan for a DML speaker from all the great work that has been shown thus far. But I think it shows that there is a lot of latitude for building these and they can still sound great. Here is what I think we need:
1. Panel material - be specific as to brand and model number.
2. Panel dimensions, height x width x thickness, rounded edges etc.
3. Type of supporting structure and where it is fastened to.
4. The brand and model of exciter(s) used - and this is where there is room for experimentation.
5. Where the exciter(s) are mounted and with what method (double sided tape, expoxy, RTV, 3M Fast Tack, etc)
6. Placement in room and distance from back wall.
7. A name for the speaker system
Thanks,
X
1. Panel material - be specific as to brand and model number.
2. Panel dimensions, height x width x thickness, rounded edges etc.
3. Type of supporting structure and where it is fastened to.
4. The brand and model of exciter(s) used - and this is where there is room for experimentation.
5. Where the exciter(s) are mounted and with what method (double sided tape, expoxy, RTV, 3M Fast Tack, etc)
6. Placement in room and distance from back wall.
7. A name for the speaker system
Thanks,
X
Hi Twocents!
Sure - I am hoping to get a recipe so I can try it myself. I am thinking of one can make it out of common building materials like ceiling tiles or XPS foam panels or even luaan wood flooring underlayment panels - that would be great.
For the FAST - maybe all we need is to high pass the exciters above 100Hz with dual back to back (bipolar) 470uF Elna Silmic caps. Use maybe 2.2uF MKP bypass caps.
Get a $100 powered 10in sub. Like a Polk PSW10 and adjust amplitude and frequency to taste.
Use a 60w Class D amp for the exciters.
Sure - I am hoping to get a recipe so I can try it myself. I am thinking of one can make it out of common building materials like ceiling tiles or XPS foam panels or even luaan wood flooring underlayment panels - that would be great.
For the FAST - maybe all we need is to high pass the exciters above 100Hz with dual back to back (bipolar) 470uF Elna Silmic caps. Use maybe 2.2uF MKP bypass caps.
Get a $100 powered 10in sub. Like a Polk PSW10 and adjust amplitude and frequency to taste.
Use a 60w Class D amp for the exciters.