Vocals, yes. That's the product that's enjoyable. But, in my non-audio skilled opinion, emphasize high quality spoken voice studio recordings (thank you, Hollywood) for testing.
Has anybody tried triple wall corrugated cardboard, such as the stuff these boxes are made from?
Triple Wall Boxes - Ameripak
Seems you can buy it in big sheets.
Triple Wall Boxes - Ameripak
Seems you can buy it in big sheets.
What I use is triple wall (1/4" thick), Staples project board. Not as thick as the cardboard you show.
Thanks, Dave
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Thanks Dave! Does it work well?
How close do you have yours to the wall & do you dampen behind it?
Where I live it’s hard to get material but I’ve got some of this stuff. COVID permitting, my parts should arrive in a week or so and I’m gonna start toying.
Planning to try try two of these on each triple board panel: DAEX25FHE-4
Have spent hours browsing this thread! What a gold mine!
How close do you have yours to the wall & do you dampen behind it?
Where I live it’s hard to get material but I’ve got some of this stuff. COVID permitting, my parts should arrive in a week or so and I’m gonna start toying.
Planning to try try two of these on each triple board panel: DAEX25FHE-4
Have spent hours browsing this thread! What a gold mine!
You're right this is a great thread.
I tried the card board alone which provided a very natural sound that I really liked, but it dropped off quickly above 8kHz. I ended up attaching Carbon Fiber (CF) fabric to one side of the card board and coated the CF with a two part epoxy. This added high end which I could EQ to give me a flat response from about 120Hz to 20kHz. The combination provides a full range natural sound. My panels are mounted in frames constrained at the edges by rubber seal material. The exciter is attached to a spline.
I have found that about 1' (or further) from the wall works well and I don't dampen behind.
Good luck with your panels!
Thanks, Dave
This is a procedure I played with some time ago. It made the panels much "Brighter" and couples the vibrations to the front surface more than just connecting to the back surface. Food for thought..
ImageShack - DML Super Tweeter
ImageShack - DML Super Tweeter
Hi everyone and thank you for all the info in this thread so far. It took me awhile to read through all 170+ pages but finally managed haha. I am definitely excited to join in on the fun. I wanted to know if anyone has contemplated to EnABL their panels? EnABL stands for Enhanced Acoustic Boundary Layer (in electronic transducers). I have done it on some of my normal speakers with success, which it’s supposedly works by trying to stop the sound waves that travel along the surface of the cone from interfering with other waves as they continuously reach the edge of the surround to help minimize resonances much like some of the topics in this thread. I probably made no sense with that haha.
I haven’t seen any recent posts on the process lately, it died down back around 2013. In simple terms someone on the forum designed a pattern of alternating dashes that you would paint on using a paint pen around resonating areas of the cone. Later on in the thread they started to combine damping with the paint dashes. The paint pattern wasn’t considered damping though because it wasn’t considered heavy enough to dampen the cone. Here is a link from the original thread that started it. You can also just search EnABL in the diyaudio forum too. There are other threads on how tos as well. EnABL is covered by a patent from Ed LaFontaine.
https://www.diyaudio.com/forums/mul...rpage=25&pagenumber=1&perpage=25&pagenumber=1
I haven’t seen any recent posts on the process lately, it died down back around 2013. In simple terms someone on the forum designed a pattern of alternating dashes that you would paint on using a paint pen around resonating areas of the cone. Later on in the thread they started to combine damping with the paint dashes. The paint pattern wasn’t considered damping though because it wasn’t considered heavy enough to dampen the cone. Here is a link from the original thread that started it. You can also just search EnABL in the diyaudio forum too. There are other threads on how tos as well. EnABL is covered by a patent from Ed LaFontaine.
https://www.diyaudio.com/forums/mul...rpage=25&pagenumber=1&perpage=25&pagenumber=1
I found this interesting article today.
(PDF) Structural Acoustics Tutorial—Part 2: Sound—Structure Interaction
The part that applies most directly to DML speakers starts on page 13, with the heading: Structural waves vibrating against an acoustic fluid
For me, the most interesting part is the discussion about how the different resonant mode types radiate power with varying efficiency. The odd,odd modes radiate the most sound power, while the even,even modes radiate the least power.
It's possible I'm misinterpreting, but this seems to explain something that I've observed, but never could make sense of until now. That something is that the exact center of a panel actually seems to be a pretty good location for the exciter.
The Azima patents and other sources suggest that the center should be a bad location for the exciter-perhaps the worst. After all, the center is the place where the most nodal lines pass through, so by placing the exciter at the center, there are lots of modes you can't excite. That should be bad, since less modes should mean less modal overlap, and hence lumpier frequency response.
However, the modes with a node in the center are the even,even modes, that don't radiate sound power well anyway. And the center is an antinode for all the odd,odd modes, and hence the center is a great place to excite all the modes that actually do radiate sound power well.
I've always wondered why the center seems to be a good place for the exciter, in spite of being at a node for so many modes. Now I think I understand why.
Eric
(PDF) Structural Acoustics Tutorial—Part 2: Sound—Structure Interaction
The part that applies most directly to DML speakers starts on page 13, with the heading: Structural waves vibrating against an acoustic fluid
For me, the most interesting part is the discussion about how the different resonant mode types radiate power with varying efficiency. The odd,odd modes radiate the most sound power, while the even,even modes radiate the least power.
It's possible I'm misinterpreting, but this seems to explain something that I've observed, but never could make sense of until now. That something is that the exact center of a panel actually seems to be a pretty good location for the exciter.
The Azima patents and other sources suggest that the center should be a bad location for the exciter-perhaps the worst. After all, the center is the place where the most nodal lines pass through, so by placing the exciter at the center, there are lots of modes you can't excite. That should be bad, since less modes should mean less modal overlap, and hence lumpier frequency response.
However, the modes with a node in the center are the even,even modes, that don't radiate sound power well anyway. And the center is an antinode for all the odd,odd modes, and hence the center is a great place to excite all the modes that actually do radiate sound power well.
I've always wondered why the center seems to be a good place for the exciter, in spite of being at a node for so many modes. Now I think I understand why.
Eric
The good thing about the center is that it's easy to locate. The linked paper has a more complicated method. My intuition is that if you use DSP you're safe in the center. I also suspect non-parallel sides helps but researches prefer materials and shapes that are easier to sell in a commercial market. Maybe a guitar or piano influenced panel is best but it would be hard to sell because it would look goofy.
Optimized Driver Placement for Array-Driven Flat-Panel Loudspeakers | ANDERSON | Archives of Acoustics
Optimized Driver Placement for Array-Driven Flat-Panel Loudspeakers | ANDERSON | Archives of Acoustics
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music file
its taken me three days to to get the upload to work plus recording ,finding old microphones with wrong plugs !
the stereo mic is from the 70s and i had to boost the bass ,the input to the laptop was very noisy ,I did try audacity noise reduction but it sounded terrible ,so its the raw recording ,the mic is about a 1mtr in front of the two panels .
the panels are slightly different but about 10 to 12 inches in size and a few mm deep.
i recommend using headphones .
steve
its taken me three days to to get the upload to work plus recording ,finding old microphones with wrong plugs !
the stereo mic is from the 70s and i had to boost the bass ,the input to the laptop was very noisy ,I did try audacity noise reduction but it sounded terrible ,so its the raw recording ,the mic is about a 1mtr in front of the two panels .
the panels are slightly different but about 10 to 12 inches in size and a few mm deep.
i recommend using headphones .
steve
Thats an interesting recording. Other than the hiss it sounds really clean. I don't know this music or recording but what I clearly hear:
1. The cymbals seem to be to the rear and left, the drums seem more centred to the rear and the wood block sounds ever so slightly to right of center. Like the whle drum set is a bit spread across the center back.
2. The vocals are right in the middle, but seem to sit in front of the drums.
3. The electric guitar is also front and center but to me seem to sound like they are a bit in front of the vocalist...thats seems weird.
4. The Bass seems to be to the left and in front of the drums, and is lacking a bit.
But none the less, the space I would expect if I was sitting in front of the group, live, seems there and seems real. Very nice overall.
1. The cymbals seem to be to the rear and left, the drums seem more centred to the rear and the wood block sounds ever so slightly to right of center. Like the whle drum set is a bit spread across the center back.
2. The vocals are right in the middle, but seem to sit in front of the drums.
3. The electric guitar is also front and center but to me seem to sound like they are a bit in front of the vocalist...thats seems weird.
4. The Bass seems to be to the left and in front of the drums, and is lacking a bit.
But none the less, the space I would expect if I was sitting in front of the group, live, seems there and seems real. Very nice overall.
Guys, OK, going to bang my panels together in the coming days.
Here is the plan:
Each “speaker” will be suspended from one of these:
Amazon.com: Honey-Can-Do GAR-01122 Adjustable Height Garment Rack, b, 33.1" x 16.7" x 65.75", Chrome/Black: Home & Kitchen
Panels will be 1/4 Inch 2 x 4 cheap plywood, with rounded corners, placed at the apparent sweet spot.
2 of the 24 Dayton exciters per panel.
Hooking up a small sub to extend the bass.
Any thoughts / tips / suggestions would be appreciated!
Here is the plan:
Each “speaker” will be suspended from one of these:
Amazon.com: Honey-Can-Do GAR-01122 Adjustable Height Garment Rack, b, 33.1" x 16.7" x 65.75", Chrome/Black: Home & Kitchen
Panels will be 1/4 Inch 2 x 4 cheap plywood, with rounded corners, placed at the apparent sweet spot.
2 of the 24 Dayton exciters per panel.
Hooking up a small sub to extend the bass.
Any thoughts / tips / suggestions would be appreciated!