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Like I've stated before DML's are similar to O.B. speakers but have a bipolar effect where sound radiates (almost) equally from the front and back. I've been watching GR Research (Danny Richie) videos on Open Baffle speakers and I've learned a lot from him even utilizing some of his techniques on my DML panels.
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First post to this forum. This thread is very helpful!
I built a couple dml speakers using the 2’ x 2’ xps project panels. My goal is to use them outside.
I used the Dayton Audio DAEX25 (5w) exciters powered by the Lepai LP-2020TI - 20 Watt amp. I think they produce plenty of volume but definitely miss the lower frequencies.
I have the ability to get 1lb or 2lb eps foam in basically any thickness and size. Would there be an ideal combination that would pair well with an outdoor sub?
Thanks in advance!
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I would get the higher density EPS. IMO Ideal thickness is around 1/4 inch (5-6mm). Size of panel is optional but like with smaller conventional cone speakers it seems that smaller panels image better. A small panel is one that is 10-12 inches in width and 14-16 inches in height if its a rectangle shape. If its a square shape then 10-12 inches even on all sides. Best all around exciter IMO is the T.E. TEAX19CO1-8. as it has the best balance of highs and lows. Coat both sides of the panels with PVA glue mixture of 80% water and 20% glue. Then you can spray paint ONE SIDE of your panels any color you want with a very light coat of gloss enamel spray paint. EPS is sensitive to corrosive chemicals so do not spray too much paint in one spot. Spray at least 2-3ft. away from panel. The side with the paint will be the front of the panel the side without the paint will be the back where the exciter will reside. Exciter placement should be close to the middle/center of the panel give or take a couple inches from the center, you need to play around to find where the best high freguencies will be close to the center. Once you find that perfect location you can either use the sticky tape that comes with the exciter to mount it to the panel but the sticky tape tends to fail after a while so if you want it permanent you can use the 5min. 2 part epoxy glue but make sure you remove the sticky tape from the exciter if using epoxy glue..Originally posted by listencarefully View Post
Its best to mount panels in a wood frame. Depth of frame can have different outcomes. A frame the same thickness as your panels will be more holographic while a frame with a deeper depth then your panels can have a more focused type of sound, its personal preference. There are many ways to mount the panel to frame and it will depend on ones design. For smaller panels I use Frost King foam all around the edges and snuggly fit it in the frame. Other methods is double sided tape or painters blue tape. Small panels should be placed on low stands so that the panels are below ear level and or you can build built in stands on the frame with just a wider piece of wood so that the frames dont tip over. You can also use a small 2inchX2inch piece of wood between the frame and wide wood to act as a decoupler. sp? lol
Since you are using a sub you dont have to run the exciter full range. If your receiver/amp does not have a high pass Xover you can just use a high pass (200uf) Nonpolarized electrolytic capacitor at around 100hz. Then you can dial in your powered sub at 100hz for low frequency.Comment
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This is SUPER helpful! I will put in the order for 12" x 14" x 1/4" 2lb EPS foam panels today.
I am hoping to use these outside. The DAEX25's are plastic coated and have a clip built in for the wire connections which makes it super easy to connect/disconnect the panels if necessary. Do you feel there is a huge difference in exciter performance? If so would you recommend a connection process for the TEAX19C01 's? -
Not a huge difference but there is a difference, and at $6.80 each or around $14.00 a pair they are cheaper and better then the Dayton DAEX25 but they dont have the spring loaded terminals.
I use these to attach to my frame and they are really cheap>https://www.parts-express.com/two-co...minal--260-300 -
Those will work! I will order them when they are back in stock.
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Ok. So I picked up my 12†x 14†x 1/4†2lb EPS foam panels today. Wow! What a difference from the 2’ x 2’ x 1’ project panels.
When I first saw them I thought they struck me as the size of a picture. So I went to the 99 cent store and picked up a couple of picture frames for $3 each.
While I was there I got some some of the epoxy you recommended and some foam mounting tape.
Will start coating and post pictures tomorrow!Comment
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Here is where I am at so far....
I purchased some 2lb EPS foam that was cut to 12" x 14" x 1/4". Here's what they look like.Originally posted by Unbiasedsound View Post
I put in an order for these but may try them out with the DAEX25's I have on hand if I get impatient. :-)Originally posted by Unbiasedsound View Post
I diluted PVA glue and painted it on the panels this morning. They still need to dry but can already see that it has made an impact on the panel surface.Originally posted by Unbiasedsound View Post
Do you like this over adding tint to the PVA solution?Originally posted by Unbiasedsound View Post
What would be a good way to test? Would mearly taping them to the back of the panel work until the best placement is found?Originally posted by Unbiasedsound View Post
I picked up some epoxy at the 99 cents store. They had both the 5 min & 90 second.
See next post....Comment
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The paint is actually used as the skin while the glue mixture is used for damping and to harden the panel.
Test each panel individually by moving the exciter around the center to find the highest frequencies then mark/circle the spot where the exciter sounds the best. If you can get someone to help you it would be even easier.
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The 99 cent store also had an assortment of picture frames. I picked up on roughly the size of my panels. I may need to trim my foam panels a little but thought it would be worth trying them out.Originally posted by Unbiasedsound View Post
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The picture frame has some metal tabs built in but I also picked up some foam tape at the 99 cents store. I also have some 3M double sided tape that I have used to hold the exciters to the back of my XPS panels.Originally posted by Unbiasedsound View Post
I was hoping to hang these on the wall. Do you think that would affect their performance significantly?Originally posted by Unbiasedsound View Post
I have a couple of 150hz High Pass filters that I purchased for my XPS panels. I also put in an order for some 100hz as you suggested. Do you feel there would be a noticeable difference using the 150's?Originally posted by Unbiasedsound View Post
Thanks for all of your help! Will post with results when I get everything put together.
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DML panels are similar to Open Baffle speakers where sound radiates from both the front and back almost equally. By hanging them on the wall it will restrict the sound coming from the back in which it could affect there performance as part of the magic from DML's comes from being able to produce sound from both sides.
Most exciters can play down to 100hz and starts dropping like a rock below 100hz so 150hz will be ok.
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Ok. I couldn't wait and finished up the speakers today. :-)
I painted one side and then put them in the picture frames. I didn't get fancy... just used the metal tabs to hold the panels in the frames. They are nice an snug.
Then I tested different locations for the exciters. That was great advice because I could definitely hear the difference as I moved them away from center. You could actually hear the sound getting tighter. I settled on a location that I felt sounded good for each speaker then marked the location with a sharpie.
I hooked them up to my amp (unfortunately my LP-2020TI is having some issues). First played them stand alone then with my Sub. These are much different than my XPS panels. Much smoother and more mid-range.
Here is a picture of them hooked up to the sub on my bench.
How do they sound?? In a word "FANTASTIC!!" The sound I am getting out of these things is unbelievable!
Can't thank you enough Unbiasedsound for walking me through this!Comment
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Nice work! Back 20 years ago I worked at an electronics retailer and we had a set of the Wharfedale Picture Speakers in a sound room. They came in a picture frame and were advertised such that people could indeed put a picture in them for true stealth tunes (they came with a hideaway woofer). IIRC they licensed the tech from NXT. I never bought a set as they were $$$ but did pick up (and still have) a set of NXT flat panel speakers that are about the size of a pair of smartphones. Neat tech indeed!Comment
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Those NXT flat panel speakers you own are they directly from NXT or licensed by NXT for the Teac brand?Originally posted by Dukk View Post
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Also you can add EQ and or DSP to further enhance the sound of your panels. DML's can have some midrange shout so using EQ can help. Reduce the 500hz band and this will reduce shout and bring out treble. Most exciters frequency response starts to drop off at around 16khz so you can boost 2db.Originally posted by listencarefully View PostOk. I couldn't wait and finished up the speakers today. :-)
I painted one side and then put them in the picture frames. I didn't get fancy... just used the metal tabs to hold the panels in the frames. They are nice an snug.
Then I tested different locations for the exciters. That was great advice because I could definitely hear the difference as I moved them away from center. You could actually hear the sound getting tighter. I settled on a location that I felt sounded good for each speaker then marked the location with a sharpie.
I hooked them up to my amp (unfortunately my LP-2020TI is having some issues). First played them stand alone then with my Sub. These are much different than my XPS panels. Much smoother and more mid-range.
Here is a picture of them hooked up to the sub on my bench.
How do they sound?? In a word "FANTASTIC!!" The sound I am getting out of these things is unbelievable!
Can't thank you enough Unbiasedsound for walking me through this!Comment
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That makes a lot of sense. I have been going back and forth between two amps. I have a Pyle PTAU55 and a LP-2020TI. the Lepai is cleaner but puts out more bass so it makes the speakers sound dull. They Pyle has a brighter sound but has a slight background hiss. May need to find a more suitable amp. Suggestions?
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I will have to have a look for them to be sure but I believe they are NXT branded. It looks like there is a similar set on ebay.ca right now.Originally posted by Unbiasedsound View PostComment
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Hey everybody
I'm trying to build some DML panels to hang from my kitchen ceiling in combo with a Dayton 10" sub. I mainly listen to jazz, funk and old rock. My current setup is built around B652 AIRs but those have to go. I got DAEX32Q-8exciters to use with 2x2 XPS panels. Problem is they sound terrible. I haven't measured them but they just have very low sensitivity and absolutely no top end. Do all DMLs need extensive post EQing, or do these particular exciters suck? If so what do people recommend?
I saw someone above had good luck with thinner + higher weight XPS... is that something I should try? I've seen a lot of people do the 2x2' panels I've done.Comment
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The pink 2X2ft. XPS panels are usually the beginners intro design into DML technology. The DAEX32Q-8 is one of the worst exciters when it comes to the higher frequencies. Sound quality is based off of ones design and most beginners design dont sound even as good as entry level conventional cone driver speakers as your B652 will sound better. EQ should be used to fine tune ones panels as it wont make a terrible sounding panel into a good sounding panel.
Thats not XPS, its EPS. XPS is usually pink or blue in color known as Extruded polystyrene while EPS is usually white and known as Expanded polystyrene. There are various densities of XPS and EPS ranging from very soft to very hard. under 1lbs and 1lbs-5lbs densities. Lower density equals lighter panels while higher densities equals heavier panels. Ideal density is not at either ends of she spectrum but rather in the middle. When a panel becomes to dense efficiency is lowered but if a panel doesnt have enough density it will lack the higher frequencies. There's compromises to make. Size and Thickness of a panel also come into play as well as the type of exciter used as not all exciters are created equally. Other factors include hanging of panels or using a frame to support panels like a bookshelf or floor standard speakers. Exciter placement on the panel is also another factor. Shape of panels makes a difference. The most accurate sounding panel shape is a square followed by a rectangle, but the rectangle should not be too long as the longer the rectangle the more exaggerated and weird it will sound due to physics. DML panels are very sensitive to changes anything touching the panel can change the sound. There are so many methods and techniques that the designs are almost endless.
I mentioned to Listencarefully about which exciter I thought sounded good and the panel density , size , shape and thickness.
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How To Build "The World's Best Speakers" - Are Flat Panel Speakers Really Any Good? - YouTube If you look into 12:40 of that vid you can see the magnet as well as the pink panels moving back and forth, this is the reason why a spine is needed to support the magnet so it has the spine to push off of and transfer all its force into the pink panel diaphragm. Without a spline with the volume turned up on heavy bass tracks the magnet without a spine will rattle because there is no support of the magnet. This rattling is caused by the weight of the magnet moving in which I believe can cause voice coil damage in the long run if playing at loud volumes with a lot of bass. You can clearly see the exciter moving in pistonic motion as the thruster exciter as well as other high powered heavy duty exciters can go into pistonic motion if driven hard enough that is why I recommend using a sub amp to push the exciter into pistonic motion as there sensitivity starts to drop like a rock below 100hz. Smaller the exciter the less pistonic motion, while the larger exciters have more pistonic motion. Any exciter under 19mm will not have any bass.
The common misconception is that exciters are not pistonic which is not true. In the low frequency spectrum they become pistonic but in the mid to highs they become modal in motion. Its just that the exciters are not efficient in the low frequencies due to the heavy plastic attached to the voice coil in which is needed to support the magnets weight as well as the heavy dml diaphragm that is why a panel needs to be light and thin. A BMR driver does not need a heavy plastic so the light voice coil is attached directly to the light diaphragm making the pistonic motion just as effecient as the higher frequencies for a more balanced sound. Also a BMR drivers magnet is supported by a frame in which it holds it in place like a spine. Most people dont realize a BMR is basically a DML exciter but using a slightly different design.
I just finished building my newest/latest design and this is one of my best satellite panels to date but I am working on another design and hopefully it will be just as good or better. Oh my bad just rambling. lol
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