DIY Flat Panel Speaker Love

[Unbiasedsound]

As some of you know, I'm one of the few on here that uses corrugated plastic as a panel material.
I don't bother much with measurements anymore. For me, what looks good doesn't a!ways sound good. Anyway, I just wanted to say that I learned something interesting about the corrugated plastic panels and how it affects sound quality.
One day while running pink noise through a panel, I placed the palm of my hand on the top edge, partially covering the flutes. The pink noise sounded "different", smoother, less hollow to my ears..
The hollow sound is something I was trying to notch out with my Mini DSP. Anyway, I sealed off the fluted ends, top and bottom and found the sound to be smoother, less hollow.
I don't try to run the exciters full range and treat them more like an ESL. For me, there's no point in running bass through them. They would have to be huge and the exciters fail easily with low frequencies.
It can be a little frustrating when I compare the exciter panels to my Magnepans. But, on their own with a subwoofer, it doesn't take long to be not only satisfied, but totally entertained with the sound.

On a side note, I bought a pair of Tectonic BMR drivers from PE (297-2156).
These things are pretty cool for a small room, 81 db SPL makes them very inefficient. That said, they sound pretty nice and have a really large sweet spot, similar to to a DML.

That hollow sound can be fixed with some dampening all around the edges of the panel.

BMR's technology came from DML technology just using different designs.

DML= Exciter, free floating

BMR= Exciter, plus a spline and brace to support and hold the exciter in place.

[sdep777]

I might try using Sonotube and glue cardboard to close off one end and see what that sounds like , kinda fun really and a cheap thrill at that.

[captainjack115]

As some of you know, I'm one of the few on here that uses corrugated plastic as a panel material.
I don't bother much with measurements anymore. For me, what looks good doesn't a!ways sound good. Anyway, I just wanted to say that I learned something interesting about the corrugated plastic panels and how it affects sound quality.
One day while running pink noise through a panel, I placed the palm of my hand on the top edge, partially covering the flutes. The pink noise sounded "different", smoother, less hollow to my ears..
The hollow sound is something I was trying to notch out with my Mini DSP. Anyway, I sealed off the fluted ends, top and bottom and found the sound to be smoother, less hollow.
I don't try to run the exciters full range and treat them more like an ESL. For me, there's no point in running bass through them. They would have to be huge and the exciters fail easily with low frequencies.
It can be a little frustrating when I compare the exciter panels to my Magnepans. But, on their own with a subwoofer, it doesn't take long to be not only satisfied, but totally entertained with the sound.

On a side note, I bought a pair of Tectonic BMR drivers from PE (297-2156).
These things are pretty cool for a small room, 81 db SPL makes them very inefficient. That said, they sound pretty nice and have a really large sweet spot, similar to to a DML.

[oTRONo]

OK, finished. I ended up gluing the panel to the canvas using spray adhesive. Worked pretty good. retained the high's except maybe above 15khz and got rid of the weird peak at about 2khz when I was using the foam in the corners to hold the panel in. Not a lot of bass, but the panels are only about 13" x 17" good enough for surrounds I think though. Now I just have to figure out how to mount to the wall and run wires.

Anyone know of a battery powered transmitter/receiver setup for surrounds so there are no wires of any kind to deal with?

[Kornbread]

I've searched, but couldn't find it ... somewhere in here I did a before and after measurement with/without hot gluing the exciter to a brace. IIRC, the results were favorable.

[oTRONo]

I did some measurements from the front (blocked by canvas) and from the open back. I'm still a newb when it comes to measuring speakers so these may not be too accurate. They are measured at about 1m using a Dayton imm6 mic. I measured my Overnight Sensations MTM modified for wall mounting as a comparison.

I see the canvas is blocking the highs somewhat and the mids are higher than my Overnight Sensations. Obviously bass output is better in the OS. SPL is about even with the Overnight Sensations though. The receiver was set at the same volume level for both.

I measured with the 3 13mm exciters connected in parallel with the 25mm also, but the graphs were almost identical. I can hear a slight difference with all 4 vs just the 25mm, but I'm not sure its better or worse, so I think I'll just stick to using the one exciter.

Next I'll do some experimenting between securing the exciter to a brace using the 4 bolt holes vs leaving it free. I'm also assuming closing the back up and wall mounting it will probably change the sound too.

[Unbiasedsound]

Most of the exciters have a strong midrange out put that over powers the treble. When I say most I mean exciters 25mm and up.....the 19mm exciters seem to have a bit less midrange blending the best of both worlds while the 13mm exciters have very little midrange sounding more like a tweeter hence why the better highs/clarity due to you using the 13mm 16ohm tectonic exciters...Bigger exciters more midrange less treble, the smaller the exciter more treble less midrange. This theory was presented by rich in which I confirmed it by trying them out....Although using crossovers can tame some of that midrange out put in the bigger 25mm and above exciters, the smaller exciters still have better highs when a cross over is utilized as well.

With DML panels it seems the greatest treble out put is radiating from the corners hence why mostly all DML panels have corners or at least rounded out corners and very rarely will you see a circular DML panel....That foam in the corner could be dampening some of the high frequency treble.

I recently got my 2 inch Hi wave BMR's and I dismantled one of them to see how they worked and they are very similar if not exactly like exciter technology as I assumed.

[oTRONo]

Ok, after some experimenting, I prefer cardboard coated with shellac inside and out over xps, eps, foamboard, and 1/4" plywood. I don't have any high quality eps so i'm not sure how that sounds. The blue Lowes xps sounds too harsh to me. The eps sounded hollow with almost no highs. The plywood sounded good but low spl. Foamboard wasn't bad (the stuff from a hobby store used for presentations and such).

Now my dilemma, I'm using the Dayton DAEX25FHE-4 and also have some Tectonic Elements HIAX13C02-16/RH 13mm Classic Exciter 16 Ohm. The Dayton sounds good, but if i put 3 of the Tectonics in parallel with it, i get better highs. The problem is it drops the impedance to 2.3 ohms. If I run the 3 Tectonics in parallel bringing them to 5.33 ohm and then in series with the Dayton for 9.33 ohms, it lowers the spl obviously but also doesn't seem to have as much bass (it could just seem that way because of the lower spl though).

Another issue, it seems the canvas is blocking a lot of the highs, there is a gap between the canvas and the panel due to the foam in the corners. I would like to try gluing the panel directly to the canvas, but I don't really want to risk damaging either of them as I wouldn't be able to remove them if it didn't work.

[TexBear]

Hi guys -
I've been listening to a couple of 2" thick 2' x 4' XPS panels that I cut out of leftover stock from insulating my old cellar door. I mounted two DAEX30HESF-4 exciters using the Monacor settings for exciters 1&2 on each panel, driving them with an old Adcom preamp/amp set. I cannot believe my ears. I've been running these since just before Christmas. I've tried going back to my old Dana Audio tower speakers, my Maggies, and KEFs. No way! Nothing compares to the open-ness, detail, and fabulous clarity I'm hearing. The only thing that seems to be somewhat lacking (not totally) is a really focused sense of horizontal soundstage. Not quite as accurate as cone speakers. However, I do seem to get a sense of foreward/backward instrument placement. Listening to some Vivaldi cello concertos, Sara Vaughn, Andreas Wollenweider, Handel symphonies and organ concertos. I just cannot believe my ears!
I've been trying to catch up on various blogs and forums on DML speakers since Christmas. Hope you're all having success in your various endeavors!
TexBear

[Unbiasedsound]

ok, thanks. I have some 1" thick EPS leftover also, this stuff here:

http://www.homedepot.com/p/R-Tech-1-...0821/202532854

I'll give that a try also. Should I remove the wood glue coating from the front surface before painting the XPS?

Another question, how would panels like these work for a home theater with a sub? I originally only planned on them for surrounds, but I'm getting ready to build some front 3 way speakers and was wondering how a full 5.1 or 7.1 flat panel setup would sound for movies compaired to traditional speakers as this is a living room and not a dedicated home theater room. The .1 being a standard subwoofer.

Thanks.

Yes, remove the glue from the front surface....First it would depend on the design of ones panels and then it would come down to personal preference....My DML 5.1 system sounds fantastic in home theater as well as for music to my ears.....For use as surround for movies they should be fine......A full 5.1 all DML panel set up will sound different then the standard traditional speakers and will come down to personal preference.

[Kornbread]

Never really like the sound of the blue styrofoam board from Lowes, no matter what, the music always had a kind of sound like when you drag a pencil eraser down the styrofoam. Tried some treated cardboard, but at the moment, can't remember the results. They should be in here somewhere.

Whatever you decide to do, take lots of pictures and post the results.

[oTRONo]

ok, thanks. I have some 1" thick EPS leftover also, this stuff here:

http://www.homedepot.com/p/R-Tech-1-...0821/202532854

I'll give that a try also. Should I remove the wood glue coating from the front surface before painting the XPS?

Another question, how would panels like these work for a home theater with a sub? I originally only planned on them for surrounds, but I'm getting ready to build some front 3 way speakers and was wondering how a full 5.1 or 7.1 flat panel setup would sound for movies compaired to traditional speakers as this is a living room and not a dedicated home theater room. The .1 being a standard subwoofer.

Thanks.

[Unbiasedsound]

I would not go smaller then 16 inches...Home Depot has the pink XPS 1inch 2X2 ft project panels for around 6 bucks.....Also I prefer the sound of EPS over XPS as EPS has a warmer sound.....a simple and easy way to tame some of that harsh frequency sound is to paint the front with either water or oil based paint.

[oTRONo]

I've been experimenting a bit with the idea of making stretched canvas wall art, like jmanes posted above, into surround speakers. I have the DAEX25FHE-4 exciter and some leftover 3/4" XPS from lowes:

https://www.lowes.com/pd/Kingspan-In...8-ft/999973072

I've cut about a 1 foot square from it to test. Rounded the corners and edges, sanded the skin off the surface and applied several coats of 50/50 water and wood glue to the front and back. The sound I'm getting from it is very harsh in some frequencies, almost like nails on a chalkboard. I'm not sure if it's because of the small panel, the coating, or because I'm only holding the exciter to the surface and not mounting it to it. I was hoping to avoid mounting it as this is only a test panel. I'm going to try sanding the coating off the front surface as some suggest only coating the exciter side. I'll try a larger panel if that doesn't work, but I don't have canvas prints yet so I don't know what size the final panels will be.

Any suggestions would be appreciated. Thanks.

[Unbiasedsound]

It says its out of stock until april 11..........I am going to try the bmr speakers as surround speakers as they seem to be very similar to exciter technology or a combination of the two like a exciter attached to a thin honeycomb cardboard with rubber surrounds on a frame. Plus if I am not mistaken bmr technology is not really new as it seems to be very similar to the old school Sonys AMP flat square speakers.