Finally finished reading the thread. It looks like most of us are experimenting with different planks with a given exciter, but not experimenting the same plank with different exciters.
All of us here are trying to create something, and that's really, really great.
Here are some of my thoughts on the plank (but, not on the exciter).
Long time ago, when we were doing architectural drawings as students, we used to pull Bristol paper over a frame, on which we drew our projects. First we pasted all four sides to the frame, and when the glue was dry, we used to wet the paper with a brush, until it became fully wet, then let it dry. Once it was dry, the paper over the frame was like a drum. The frame had to be braced, before wetting the Bristol paper, otherwise it'd crack. I was thinking, why not use such a tightened paper as the panel, with the frame, of course with the frame?
Considering that, why not use a drum as a panel/open-box to create a DML? Or, something like this?
Also, why not use an open box, such as shelf without doors, and fix the exciter on to the back of the box/shelf? Or, add a somewhat wide frame around the existing panels you have?
I cannot get a Dayton, Monacor or Visaton exciter, where I live. Even, if I import it, it would be more expensive. As all of those are made in China, I might buy the "officially" Chinese exciters from Aliexpress, which are about 25% of the cheapest Chinese made Dayton.
All of us here are trying to create something, and that's really, really great.
Here are some of my thoughts on the plank (but, not on the exciter).
Long time ago, when we were doing architectural drawings as students, we used to pull Bristol paper over a frame, on which we drew our projects. First we pasted all four sides to the frame, and when the glue was dry, we used to wet the paper with a brush, until it became fully wet, then let it dry. Once it was dry, the paper over the frame was like a drum. The frame had to be braced, before wetting the Bristol paper, otherwise it'd crack. I was thinking, why not use such a tightened paper as the panel, with the frame, of course with the frame?
Considering that, why not use a drum as a panel/open-box to create a DML? Or, something like this?
Also, why not use an open box, such as shelf without doors, and fix the exciter on to the back of the box/shelf? Or, add a somewhat wide frame around the existing panels you have?
I cannot get a Dayton, Monacor or Visaton exciter, where I live. Even, if I import it, it would be more expensive. As all of those are made in China, I might buy the "officially" Chinese exciters from Aliexpress, which are about 25% of the cheapest Chinese made Dayton.
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The end of a hard lock down on my side has resulted in much less time for DIY projects, perhaps this is a common trend?
I experience the same – threads (in general) are not so active because members are not so active, including me. Only certain members in the UK seem to have time to build and experiment.
My DML aspirations and plans certainly came to a grinding halt when my exciters got “locked down” in Shanghai. I gave up on ever getting them. I have since started a different little FR project but also find little time to finish them.
Moldie, I was hoping that you would have built and come up with some groundbreaking experiments and new ideas by now. I am sure a lot of members are still lurking and also waiting for new ideas and findings. We look forward to your results.
My DML aspirations and plans certainly came to a grinding halt when my exciters got “locked down” in Shanghai. I gave up on ever getting them. I have since started a different little FR project but also find little time to finish them.
Moldie, I was hoping that you would have built and come up with some groundbreaking experiments and new ideas by now. I am sure a lot of members are still lurking and also waiting for new ideas and findings. We look forward to your results.
Moldie, I was hoping that you would have built and come up with some groundbreaking experiments and new ideas by now. I am sure a lot of members are still lurking and also waiting for new ideas and findings. We look forward to your results.
Alas laziness has overcome. At least have half a new idea constructed. Very large thin ply panel, clamped at the bottom by rubber and a 3d printed wedge. Idea being that bending the plywood will stiffen it enough to stand upright if only supported from the bottom.
A 12inch embroidery hoop would seem a good choice for testing different materials to be stretched,cotton,paper ,card,and coatings of pva?
And to see how these compare to canvas .
My square card panel has a bend from top to bottom,this seems to restrict LF in this direction.
Placing weights on the flat sides increases LF but does nothing on the curved side.
So at the moment I'm trying to keep my panels as flat as possible.
Chdsl.
I'm a little confused by the words,plank, empty shelf,empty cupboard?
Putting an exciter in a box will sound like an exciter in a box.
I'm not sure if this is what you are saying,but please let me know if I'm wrong.
Steve.
And to see how these compare to canvas .
My square card panel has a bend from top to bottom,this seems to restrict LF in this direction.
Placing weights on the flat sides increases LF but does nothing on the curved side.
So at the moment I'm trying to keep my panels as flat as possible.
Chdsl.
I'm a little confused by the words,plank, empty shelf,empty cupboard?
Putting an exciter in a box will sound like an exciter in a box.
I'm not sure if this is what you are saying,but please let me know if I'm wrong.
Steve.
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Sorry about that. Plank is a long narrow piece of wood or material. There could be wide planks. About the empty box, the exciter has to be placed on the outside. That's why I was thinking of adding a flat frame (at 90 degrees) around the panels you have.
Sound waves, like all waves move out from the source in every direction, which means they move away radially. As we are talking about tiny waves moving away from the exciter (the source) on a panel, they have to move like a flower away from it. So, the panel has to be a round one, not a square or rectangular one. Remember the childhood days, when we created a telephone with 2 cups and a string? So, if we have round panel, as thin as possible, and with a thin protruding frame around it, it would be like that cup.
Maybe, because of the 90 degrees frame, the sound might be directed. Maybe, the frame could be a wider cone.
Also, the surface waves happen more on the side of the panel, the exciter is connected, rather than the other side, if you are fixing the exciter on the back, the panel has to be as thin as possible, hence a paper.
When the panel is thick, the waves created by the exciter has to go through the thickness of the panel to the listening side. These waves, and the waves on the listening side could be (most probably) are much different than the waves on the back surface, where the exciter is fixed.
I think, one has to completely forget about how the the standard speakers work, when considering panels as sound producers.
So, what if a flat thin large round panel is fixed on a voice coil, rather than a cone of a standard speaker, and its perimeter supported on the surround? It'd still push air, but less than a cone. But, depending on the way the surround is fixed the movement of air could be adjusted.
The "exciter" is only "vibrating" to and fro, just like a standard speaker, only on a smaller scale.
The "exciter" is only "vibrating" to and fro, just like a standard speaker, only on a smaller scale.
The word DML doesn't talk about waves. DML or Distributed Mode Loudspeaker is a coined expression. An "exciter" "vibrates" only in one direction, to and pro at 90 degrees. By mentioning "distributed mode," we try to move away from waves. I've been reading all the patents that were linked in the posts here. In a way, all those people applying for patents were not really sure of what they were trying to explain. All they knew was some vibrating element would make some rigid panel give out sounds. Then, went on to make all kinds of equations. They were maybe right, or wrong, it is your ear that would tell you what you hear, not the equipment, or graphs.
Anything that vibrates, if touches a surface would give out a sound. Just lightly touch a surface with a electric screwdriver and it would give sound.
I read all the posts here. It took a long time. I like the way people experimented. Whatever graphs they showed, it was their ear that told them what they heard, was it nice or not, or was that different than a standard speaker's output.
I remember seen a post, where one person had mounted his exciter to a disk and then glued that disk to a tight canvas. He mentioned that the sound it gave was very nice. I've also seen youtube videos, where some people had taken the cone off and brought the to and fro vibration to a panel. Right now, it is only to and fro movement in any "exciter" or in any standard driver. Every source element that vibrates to artificially create sound vibrates to and fro. One pushes the air, and the other create waves on anything it touches. Even the standard conical driver that pushes air, when placed on/against a panel, the panel would give sound.
Anything that vibrates, if touches a surface would give out a sound. Just lightly touch a surface with a electric screwdriver and it would give sound.
I read all the posts here. It took a long time. I like the way people experimented. Whatever graphs they showed, it was their ear that told them what they heard, was it nice or not, or was that different than a standard speaker's output.
I remember seen a post, where one person had mounted his exciter to a disk and then glued that disk to a tight canvas. He mentioned that the sound it gave was very nice. I've also seen youtube videos, where some people had taken the cone off and brought the to and fro vibration to a panel. Right now, it is only to and fro movement in any "exciter" or in any standard driver. Every source element that vibrates to artificially create sound vibrates to and fro. One pushes the air, and the other create waves on anything it touches. Even the standard conical driver that pushes air, when placed on/against a panel, the panel would give sound.
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The person, who made panels with "exciters" pasted on to a disk and on to canvas. https://www.diyaudio.com/forums/full-range/272576-study-dmls-range-speaker-92.html#post6005822
Sinead O'connor
This is just a quick recording of test tweeter materials on card panels.
The panel on the right is an old panel 14x10inch card painted in pva then vynil silk.
I cut out the centre of the exciter area and replaced with a foil dome.
This as usual was played at high db but I had to lower the mic input by 9db to try and stop the AGC from cutting in (unsuccesfully ).
Steve.
This is just a quick recording of test tweeter materials on card panels.
The panel on the right is an old panel 14x10inch card painted in pva then vynil silk.
I cut out the centre of the exciter area and replaced with a foil dome.
This as usual was played at high db but I had to lower the mic input by 9db to try and stop the AGC from cutting in (unsuccesfully ).
Steve.
This is the frequency response of the right panel.
The first pic on the left is at 1mtr and the second on the right is at 3mtrs.
I only had the LF running up to 100HZ ,so there was a large dip in the response until the panel started to take over at about 200hz.
Steve
The first pic on the left is at 1mtr and the second on the right is at 3mtrs.
I only had the LF running up to 100HZ ,so there was a large dip in the response until the panel started to take over at about 200hz.
Steve
Attachments
Intaud.
Well over 10 years ago, when I first started testing panels ,I could get hold of circular 3ft cc panels,these were only a few mm thick ,at the time i thought they sounded great.
I mounted the exciters at the two thirds point.
By chance this ment that the only direct parallel sides the exciter received was the top and bottom.
If the exciter were placed in the centre , the exciter would received a massive reflection from the circle edge,causing problems.
Small circular panels would have bigger problems than larger more lossy panels.
Cones and bmr use roll surrounds to heavily damp these reflections.
This link shows my early circular cc panels.
Steve
(Untitled)
Well over 10 years ago, when I first started testing panels ,I could get hold of circular 3ft cc panels,these were only a few mm thick ,at the time i thought they sounded great.
I mounted the exciters at the two thirds point.
By chance this ment that the only direct parallel sides the exciter received was the top and bottom.
If the exciter were placed in the centre , the exciter would received a massive reflection from the circle edge,causing problems.
Small circular panels would have bigger problems than larger more lossy panels.
Cones and bmr use roll surrounds to heavily damp these reflections.
This link shows my early circular cc panels.
Steve
(Untitled)
But, there aren't any square or rectangular "exciters," are there? All of them are round and there is a round coil that moves or vibrates, but always to and fro, at 90 degrees to hole in the magnet, and that too is round.
Come to think of it, the cone in a standard speaker driver, while moving to and fro, also vibrates on its cone surface. Those tiny vibrations on the surface of the cone that changes the movement of air next to it (or frequencies) that makes sound, different sounds, depending on the given spot, or a thin circle, rather than the whole cone pushing a mass of air of its volume to and fro. Considering the whole cone pushing a mass of air as whole would give only one sound, not many. A speaker gives many at the same moment. If you touch the cone with your fingers, when the speaker is on, you'd feel the difference at different points, or move your finger along radially from the bootom to top, or sideways.
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Of course, everyone here knows how a speaker is made. Anyway, here 2 interesting videos.
How a speaker driver is made at a factory.
This is a DIY making of speaker drivers, both a woofer and a tweeter. Around 1:02 to 1:07 minutes into the video, you'd see how the table became the speaker. It'd be interesting to watch whole video.
How a speaker driver is made at a factory.
This is a DIY making of speaker drivers, both a woofer and a tweeter. Around 1:02 to 1:07 minutes into the video, you'd see how the table became the speaker. It'd be interesting to watch whole video.