DIY Flat Panel Speaker Love

[rmeinke]

Re: DIY Flat Panel Speaker Love

I got one driver back in March, and its back-ordered twin just arrived yesterday (DAEX32EP-4). I have a neighbor with some foam board insulation he wants to get rid of, so hopefully I will get to try something soon. I've got some health issues, so my progress will be really slow. I mainly wanted to thank all you guys for the cool ideas in this thread. I am sure I will be amazed at sound coming out of a piece of rigid foam! I am hoping these will work well as surrounds in a 5.1 system, or maybe just some fun speakers for the basement workshop (impervious to sawdust).

Hey John, sorry to hear of your health issues. Luckily these are easier to build than most any other DIY speaker... and are light and simple. In any event, welcome to the DML panel thread man! ;)

You will be happy with the DAEX32EP-4 and while I only do 2 channel, all reports on DML panels for HT is that they are absolutely outstanding. The clarity and detail provide excellent voice intelligibility. I was really surprised at the output from even my small 12x14.5 inch panels which play down to 180Hz. Even a 14x20 inch panel would likely go low enough to mate with a sub... so if you don't have the space for large panels the small ones ought to be perfectly fine. The clarity and detail was even better on a smaller panel and did a total disappearing act in the room.

Hope the health improves and definitely report back whenever you get the time to build and please holler if you have any questions!

Here is one of the recent posts from AC on HT... apologies if I posted this already...

Just wanted to tell ya'll a little story. This morning we had a babysitter so the little lady and I could have some kiddo free time so we decided to go see a movie. Found one we wanted, went and got all our goodies, finally movie time. Room goes dark, screen comes on............
.....aaaaaannnnddddd total disappointment. She and I looked at each other and with faces scrunched up and said almost in unison " This sounds like crap"

We have been spoiled by our panels. The sound in the theater was muffled, veiled, and not distinct. Not to mention a lack of bass. No kick in the chest, no sense of directionality, no wow factor. The theater was a THX rated room and I was bored. If I ever doubted having my own panels and movie room, it was dispelled today. We will NOT ever be going back to the expensive tickets and concessions again. Henceforth we will watch from the comfort of our own home with our own reasonably priced snacks, and dare I say it, yes, even in my underwear if I damn well please!


To anybody lurking here or on the fence about these panels, DO IT! It is fairly cheap and you will love the sound from them!

[rmeinke]

Re: DIY Flat Panel Speaker Love

I'm thinking of putting a couple of these together to try out in my 14x22ish family room that has vaulted ceilings. Each would be 3'x4' (or so) 3/4" XPS, EACH with a pair of
Dayton daex25fhe-4, framed high-efficiency 25mm exciters (24w, 4-ohm), wired in series and positioned as described in the Parts Express exciters buyers guide.

If they work reasonably well, I may also make variations with different sizes, thicknesses, and shapes (preferably trapezoidal), and post some measurements.

I'm posting to get reactions from you folks - encouragement or discouragement, what to do, what to avoid, etc.

Fire away.
Judd

Hello Judd!
Boy, that is a wide panel my friend but if you have the space they will go deep no doubt. However, if I were to build a panel that size I would most certainly go with the 1" XPS material. A 3/4" panel that size will not be stiff enough and will produce the typical sharp peek and deep (an estimated 25 and 65Hz) on XPS but ought to be even more pronounced unless to do more substantial suspension on the edges. Even with heavier suspension I'd still go with the 1" XPS and possibly another coat of the PVA:water treatment.

2 exciters will give you more output but will lose some panel magic due to interference/cancellation between the exciters attempting to excite the same area on the panel. If you really need the additional output I understand, but I'd go with 1 exciter first then add the second one after you verify that the output isn't enough.

If you have the extra exciters, why not build a 2 panel array?

[juddwilcox]

Re: DIY Flat Panel Speaker Love

Thanks for the guidance, rmeinke. I will certainly go with 1" but, to start, I was thinking no suspension. Bad idea? My avr isn't 4ohm-stable so I'm using a pair of exciters wired in series to get 8ohm impedance. I was thinking to mount them as close together as I could to minimize interference. Different ideas are welcome...

[dlneubec]

Re: DIY Flat Panel Speaker Love

Perhaps I missed this discussion, but how is everyone attaching these to their panels? Using the built in adhesive? If so, are these a use once and discard scenario or has a way been discovered to use them on multiple panels? Anyone try attaching them to a small intermediary panel that can then be moved from one panel to another for testing different sizes, shapes and materials?

I envision a multi-panel solution where different shapes or materials are combined that work best for a particular frequency range.

[bolland83]

Re: DIY Flat Panel Speaker Love

I think it was mentioned earlier that it can be removed (carefully) with a putty knife or something similar and then re mounted with hot melt or epoxy. I haven't tried it yet myself though.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Perhaps I missed this discussion, but how is everyone attaching these to their panels? Using the built in adhesive? If so, are these a use once and discard scenario or has a way been discovered to use them on multiple panels? Anyone try attaching them to a small intermediary panel that can then be moved from one panel to another for testing different sizes, shapes and materials?

I envision a multi-panel solution where different shapes or materials are combined that work best for a particular frequency range.

I use the VBA that comes preattached to the exciters voice coil but it is a one time attachment. Bolland is spot on... to reuse they are easy to remove with a knive/putty knive. I just sand and reapply the PVS:water treatment where the exciter was attached. I then use Elmer's ProBond to reattach. Others use PVA/waterproof PVA.

On the intermediary panel, I did not have good luck with the DAEX58FP given the large plastic "boot"... was a huge disappointment. At frequencies where the wavelength is shorter than the voice coil, much of the HF output comes from the small area inside of the vc. The DAEX58FP lacked the detail and clarity that I got from the cheaper DAEX25FHE-4 so I would be concerns that the small intermediary panel would reduce clarity and detail much like the plastic boot.

Would also have to question the usability and if anything is actually gained by using an extra panel. To move the exciter to another panel, instead of remove a small exciter, you would have to remove the extra panel which in my opinion would be harder than removing a small exciter. Just removing the exciter is easier unless you have a good approach that I just don't see. :-)

On different shapes, sedge over at AC has a room full of different panels of various shapes and sizes and he explains the quest as switchbacks and roundabouts. Certainly can't hurt to try different things but I would also say that much has been tried over the years and have not seen any shapes that have an advantage over rectangular panels. Similar with combining materials... this has come up a number of times and I don't know of any successful designs combining different materials. But if you have some specific designs in mind built and test it.. thats half the fun man!

[juddwilcox]

Re: DIY Flat Panel Speaker Love

I'm hoping to experiment this weekend with a large panel with 2 25mm exciters wired in series. One variation I plan to try is to mount the second exciter, piggyback style, on top of the first. Interested in that result.

[dlneubec]

Re: DIY Flat Panel Speaker Love

I'm hoping to experiment this weekend with a large panel with 2 25mm exciters wired in series. One variation I plan to try is to mount the second exciter, piggyback style, on top of the first. Interested in that result.

I was thinking about mounting a pair directly opposing front and back and test them in a push push configuration. I'm interested in seeing if opposing, in phase drivers might help to control spurious panel vibration, as does a push push coupled driver mount in a box.

I've been wondering if some of the sound on the panel is propagated just along the surface the driver is mounted on and is not transferred or is only partially transferred to the front surface of the panel. This might be why the glue coat is important. In that case, perhaps some of the comments about the sound appearing to come from behind are due to having the driver mounted on the back of the panel and something is lost as the vibration moves through the panel to the front side.

[rmeinke]

Re: DIY Flat Panel Speaker Love

I was thinking about mounting a pair directly opposing front and back and test them in a push push configuration. I'm interested in seeing if opposing, in phase drivers might help to control spurious panel vibration, as does a push push coupled driver mount in a box.

I've been wondering if some of the sound on the panel is propagated just along the surface the driver is mounted on and is not transferred or is only partially transferred to the front surface of the panel. This might be why the glue coat is important. In that case, perhaps some of the comments about the sound appearing to come from behind are due to having the driver mounted on the back of the panel and something is lost as the vibration moves through the panel to the front side.

I initially wondered the same thing about the sound to appear to come from behind the panel. So I spun the panel around and listened to it with the exciter on the front but there was very little difference and the diffused sound quality was still present.

There may be an issue with mounting exciters on opposing surfaces. At high frequencies when the frequency is shorter than the diameter of the voice coil much of the high frequencies comes from the area between the voice coil/panel. Its been explained as an oil can effect which is a bit harsh to label as such but you get the idea. Having the exciters occupy the same space will impact high frequencies.

This is a good video discussing how HF are generated by the panel and exciter - https://www.youtube.com/watch?v=GJiyndZaX_4

[rmeinke]

Re: DIY Flat Panel Speaker Love

I'm hoping to experiment this weekend with a large panel with 2 25mm exciters wired in series. One variation I plan to try is to mount the second exciter, piggyback style, on top of the first. Interested in that result.

Just wait... what?!?

Meaning to mount one on the other? Peel off the VHB on one exciter and mount it to the back of the other? interesting. Not sure what that would do. Will be interesting to hear the result.

good luck fellas with your work this weekend!!

[juddwilcox]

Re: DIY Flat Panel Speaker Love

Keep in mind that my goal is to present an 8Ohm load to my HT receiver, not to get a louder panel. If PE had a positively reviewed 32mm 8Ohm exciter then I wouldn't be down this path at all.

To get to 8Ohm I plan to use two 4Ohm exciters wired in series, mounted either on a single or on two separate panels. As I understand it, two exciters on the same side of one panel - even next to each other - can cause interference on the panel and, as rmeinke puts it, "lose some of the magic." Naively, I could guess this to be the case but, regardless, others' experience supports the idea.

Therefore, my first thought was to "piggyback" - you interpreted that correctly, rmeinke - but, after thinking about it some more it seems that may lead to overexcursion problems in the "inner" exciter. At the moment, I prefer dlneubec's idea of mounting exciters in the same location on both sides of the panel. A push/pull configuration makes more sense to me than a push/push but it'll be easy enough to try both. In a push/pull, if SQ suffers because the exciters aren't exactly in phase, the two exciters could even be forced into lock-step by bolting the frames together through holes in the panel. Not sure if this, over time, would tear up the exciters or not but at least it's an option.

[dlneubec]

Re: DIY Flat Panel Speaker Love

Keep in mind that my goal is to present an 8Ohm load to my HT receiver, not to get a louder panel. If PE had a positively reviewed 32mm 8Ohm exciter then I wouldn't be down this path at all.

To get to 8Ohm I plan to use two 4Ohm exciters wired in series, mounted either on a single or on two separate panels. As I understand it, two exciters on the same side of one panel - even next to each other - can cause interference on the panel and, as rmeinke puts it, "lose some of the magic." Naively, I could guess this to be the case but, regardless, others' experience supports the idea.

Therefore, my first thought was to "piggyback" - you interpreted that correctly, rmeinke - but, after thinking about it some more it seems that may lead to overexcursion problems in the "inner" exciter. At the moment, I prefer dlneubec's idea of mounting exciters in the same location on both sides of the panel. A push/pull configuration makes more sense to me than a push/push but it'll be easy enough to try both. In a push/pull, if SQ suffers because the exciters aren't exactly in phase, the two exciters could even be forced into lock-step by bolting the frames together through holes in the panel. Not sure if this, over time, would tear up the exciters or not but at least it's an option.

I hope you do try mounting them on opposing sides of the panel. Push push was conceptually about vibration cancellation to possibly stabilize the panel. However, that might cause massive damping that ruins the response. Push pull would be equally on the agenda for testing, if it were me.

Something new may be learned and if it turns out that high frequencies are compromised but low and/or mid performance is improved, then perhaps a two panel system with each panel optimized for its own frequency range would be a reasonable approach. If you separate the panels slightly, then I would think any compromise of the panel magic should be mitigated. This would be another approach to get you to 8 ohms.

I'd be willing to bet that certain combinations of panel sizes, materials and exciters would optimize specific ranges of frequencies. A speaker could be made up of two different panels sizes, two different materials, two different exciters, etc. Essentially a two-way-like panel setup but done acoustically, not electrically, though you could consider combining some active or passive manipulation as well.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Keep in mind that my goal is to present an 8Ohm load to my HT receiver, not to get a louder panel. If PE had a positively reviewed 32mm 8Ohm exciter then I wouldn't be down this path at all.

To get to 8Ohm I plan to use two 4Ohm exciters wired in series, mounted either on a single or on two separate panels. As I understand it, two exciters on the same side of one panel - even next to each other - can cause interference on the panel and, as rmeinke puts it, "lose some of the magic." Naively, I could guess this to be the case but, regardless, others' experience supports the idea.

Therefore, my first thought was to "piggyback" - you interpreted that correctly, rmeinke - but, after thinking about it some more it seems that may lead to overexcursion problems in the "inner" exciter. At the moment, I prefer dlneubec's idea of mounting exciters in the same location on both sides of the panel. A push/pull configuration makes more sense to me than a push/push but it'll be easy enough to try both. In a push/pull, if SQ suffers because the exciters aren't exactly in phase, the two exciters could even be forced into lock-step by bolting the frames together through holes in the panel. Not sure if this, over time, would tear up the exciters or not but at least it's an option.

Hey Judd, hope you didn't take any comments as criticisms... I love the creativity man. Test different configurations is fun so don't be afraid to try something different... something is always learned!

[rmeinke]

Re: DIY Flat Panel Speaker Love

Keep in mind that my goal is to present an 8Ohm load to my HT receiver, not to get a louder panel. If PE had a positively reviewed 32mm 8Ohm exciter then I wouldn't be down this path at all.

To get to 8Ohm I plan to use two 4Ohm exciters wired in series, mounted either on a single or on two separate panels. As I understand it, two exciters on the same side of one panel - even next to each other - can cause interference on the panel and, as rmeinke puts it, "lose some of the magic." Naively, I could guess this to be the case but, regardless, others' experience supports the idea.

Therefore, my first thought was to "piggyback" - you interpreted that correctly, rmeinke - but, after thinking about it some more it seems that may lead to overexcursion problems in the "inner" exciter. At the moment, I prefer dlneubec's idea of mounting exciters in the same location on both sides of the panel. A push/pull configuration makes more sense to me than a push/push but it'll be easy enough to try both. In a push/pull, if SQ suffers because the exciters aren't exactly in phase, the two exciters could even be forced into lock-step by bolting the frames together through holes in the panel. Not sure if this, over time, would tear up the exciters or not but at least it's an option.

Oh, forgot to say, the Tectonic Elements TEAX25C10-8/SP 8 ohm exciter looks really good to me. I have 6 in my cart right now actually. I want to do a double panel to get a 4 ohm load for increased sensitivity and power handling. The Fs is low and the BL is high. An option for you if you want a single exciter and panel.

But I like were you are though... I think 2 panels (1 exciter per panel) is an excellent (and personally... preferred) approach for improved power handling, output and sensitivity. If you want to make it easier to build a double panel, I have wondered if a single large panel with 2 cuts into the surface (opposing 1/4" cuts per side)... effectively dividing the panel... would reduce or eliminate most high freq. cancellation due to 2 exciters placed on the same panel. Been meaning to try this configuration.

[buke9]

Re: DIY Flat Panel Speaker Love

Hello all,
I just started to get back into decent audio and found this site after looking to fix a pair of speakers. After perusing the site I found this thread ( read almost all of it ) and this looks like too much fun not to give a shot. I have zero experience in speaker building but I was thinking of giving it a shot then I found this. Being a new guy to this please excuse any dumb questions. One question I have is what amp to run a pair of these? I have a few amps but most are higher powered than most of the exciter power handling rating. I have a Hafler TA 1100 that is 45 or 50 watts that can do 4 ohm speakers and a old NAD 7125 receiver that I believe is 25 watt that can also do a 4 ohm load. Would either one of these work with this project? I was thinking of trying out a pair of Dayton Thrusters to start with as the Ultras are out of stock. Any thoughts on this would be great. Thanks for any and all replies.
Brent