DIY Flat Panel Speaker Love

[stinems]

Re: DIY Flat Panel Speaker Love

rmeinke, in all this experimenting, how do you affix the transducer to each new panel iteration? Or have you been buying loads of these transducers because they're cheap? Or, put another way, how permanent is the VHB adhesive?

Also, the DAEX25FHE and maybe others have the mounting frame. Have you used that at all, or just been relying on the adherence to the panel?

Cheers,
Sam

[rmeinke]

Re: DIY Flat Panel Speaker Love

Does the treatment improve efficiency? I would think the added weight would reduce the SPL.

I can't say that it doesn't impact efficiency but the mixture is pretty thin so I don't think it impacts it in any meaningful way. Even if it does, it marginal but the sound quality improvement that it brings over an untreated panel is not. It is a must for performance reasons.

[rmeinke]

Re: DIY Flat Panel Speaker Love

rmeinke, in all this experimenting, how do you affix the transducer to each new panel iteration? Or have you been buying loads of these transducers because they're cheap? Or, put another way, how permanent is the VHB adhesive?

Also, the DAEX25FHE and maybe others have the mounting frame. Have you used that at all, or just been relying on the adherence to the panel?

Cheers,
Sam

Hello Sam,
For attaching exciters I do VHB if I know I'll be reattaching the exciter for more tests. But I have also reattached with a permanent glue (Elmer's Probond Advanced) to listen to a panel with a hard bond. VHB is soft and will impact the high frequency response if even a little. For an audiophile panel I would use a hard drying glue every time.

But I have been buying extra exciters too...

I started with the DAEX25FHE as I had thought that a spline mounted exciter was the only way that these panels would perform well. However others before me that had invested pretty significant time into building and listening to these DML panels slowly went away from rigid spline mounting... so I was wrong with my initial take on the best mounting technique. Whats new.

The one aspect that I didn't factor in for a rigid spline mount is the fact that the spline and frame become part of the music reproduction chain. These exciters are more powerful than you would imagine and a spline with 4 or more exciters really do exert a pretty significant amount to force on the spline and frame and HAS to make a reasonable impact on the measured and musical performance.

I do want to validate this via measurements now that I have OmniMic. I have noticed that my (mostly) free standing DML panels do not *appear* to act very well behaved in the Energy-Time curve as measured by OmniMics and wonder if hard-mounting would help or hurt panel performance in this respect. But this might be a measurement challenge with any DML panel as high frequencies are generated over the entire panel surface. I would ask the measurement experts out there... how would a 24 in. x 30 in. panel with tightly packed tweeters measure in the time domain? As the frequencies rise so does the time delay. Bass appears to be very well behaved... just the opposite of what we see with CSD waterfall plots for cone/dome drivers.

Been busy the last few weeks so haven't had the time to measure and listen much. So I guess I'll have to get back to you on the spine mounting... :(

[stinems]

Re: DIY Flat Panel Speaker Love

I see now that I worded my question very poorly. What I'm trying to verify is that, when you use the VHB adhesive for testing/prototyping, its not such a "high bond" that you can't peel it back off a panel without ruining the panel and/or the transducer? And then, is the adhesive still sticky enough to reuse on some other prototype panel?

[vega406]

Re: DIY Flat Panel Speaker Love

Just FYI, looks like the exciters (both versions) are on sale for ~$3 off each. The thrusters are $14.30 each and the ultra's are $14.00 each. Think i'm going to grab a pair or two!

[rmeinke]

Re: DIY Flat Panel Speaker Love

I see now that I worded my question very poorly. What I'm trying to verify is that, when you use the VHB adhesive for testing/prototyping, its not such a "high bond" that you can't peel it back off a panel without ruining the panel and/or the transducer? And then, is the adhesive still sticky enough to reuse on some other prototype panel?

Sorry Sam, I gotcha now.

With either glue or VHB I can pry off the exciter with a knife. In both cases it removes some of the panel treatment. I flip the panel and re-position in a "clean", unused location. Sometimes I sand the panel smooth where the exciter was and reapply the PVA:water treatment... other times I don't... don't think it really impacts performance.

The exciter can only be attached once, the VHB is done after a single mount. Not reusable on treated XPS/EPS at least.

So one use and done for VHB. So with no real reuse, I'd use whatever is cheapest. Though if in a hurry, VHB is a stick and done... no waiting for glue to dry.

[vega406]

Re: DIY Flat Panel Speaker Love

Do you have any close up pictures of your steps to create your panel? I might be over-thinking things. My questions below:

1. Round the corners. I use a 6 in diameter bowl to mark the line and cut the panel with a steak knife. I will go smaller in my next build; 3 inch diameter should be fine. - got it and makes sense

2. Break the edges with a quarter-round router bit. This is just to rough out the edge... rough is the key word. - little confusing and hard to picture. I do not have a router at this time. Are you effectively rounding the edges on the front and back side slightly? I'd like to see what "rough" means in this context

3. With a palm sander + 100 grit, sand front and back of the panel removing the XPS dust before it builds up as it can leave heavy swirl marks. It will have swirl marks either way but I try to keep the panel as clean and smooth as possible. I usually finish with 220 grit but the last time I didn't and the panels looked about the same. - got it and makes sense

4. Hand sand the rough quarter-round edges with 100 grit to straighten the lines and round the edges uniformilly. I finish the edges with 220. - goes along with step 2 for me

5. Treatment : After mixing the treatment, I roll it on with a foam roller to front and back but try not to get it on the edges. Some folks don't treat all the way to the edge, leaving about an inch but I go right up to where the panel begins to round over. I use a hair dryer to dry the panels so I can get through the treatment quickly. - got it and makes sense


I'm ready to build a set and will be placing my PE order probably today to get the exciters coming in. I will probably buy a pair of the ultra and a pair of the thrusters to try. Is the 2x3 ish size still the standard that you would recommend?

Thanks,
Josh

[rmeinke]

Re: DIY Flat Panel Speaker Love

Just FYI, looks like the exciters (both versions) are on sale for ~$3 off each. The thrusters are $14.30 each and the ultra's are $14.00 each. Think i'm going to grab a pair or two!

Sweet!!! But dang... and I just got 4 more of the Ultra's a few weeks ago... (*&^^%*%^*

I'm going to stock up possibly on both the Thruster and the Ultras. But have to say, the Ultra's are amazing on XPS. The family was away last night for a few hours so I got to listen at more realistic levels and holy sh!t do the Ultras sound fantastic!!

The Ultras sounded better than the Thruster from minute 1... with no break in. That is impressive enough. But last night the Ultras really started to open up and are amazing transducers. With the diffused sound of a DML panel, I do still notice what comes across as hazy compared to a cone/dome. Not lacking in detail or polite, but it is a different presentation that has been noted in the Podium Sound DML panel reviews.

I have not listened to the Podiums... but knowing what exciters they use and the number on the panel, I would venture a guess that the Ultra's on treated XPS could equal or possibly even outperform them in some areas. They really do sound that good. I heard more of the acoustic space in Muddy Water's Folk Singer than I can ever remember by any speaker.

Vega... I'd go with the Ultra's despite their fragile nature. For $14 you can buy extras in case of a failure... chump change.

What type of material and size are you building??

[vega406]

Re: DIY Flat Panel Speaker Love

I am actually just planning to follow whatever your best recommendations are. It looks like the 30x24 panels would work well. I will probably just use the same XPS that you noted as well. I will probably purchase a pair of each (ultra and thruster) just to play around with. I'm not sure where i'll put them, but they are a cheap project and look fun to work with. This should hold me off before I do my Statements II build later this spring/summer.

Unless you have other recommendations i'm always up for building a tried and true setup. Maybe i'll design stuff later, but for now I am happy with success :D

Thanks,
Josh

[JeffKnob25]

Re: DIY Flat Panel Speaker Love

Maybe I missed it somewhere but which thickness of XPS is best for a 30x24 panel?

[rmeinke]

Re: DIY Flat Panel Speaker Love

I am actually just planning to follow whatever your best recommendations are. It looks like the 30x24 panels would work well. I will probably just use the same XPS that you noted as well. I will probably purchase a pair of each (ultra and thruster) just to play around with. I'm not sure where i'll put them, but they are a cheap project and look fun to work with. This should hold me off before I do my Statements II build later this spring/summer.

Unless you have other recommendations i'm always up for building a tried and true setup. Maybe i'll design stuff later, but for now I am happy with success :D

Thanks,
Josh

Hey Josh!
If you need to place them in a room and have them look as good as they sound () I would do 2 panels per side array. I want to finally finish a panel speaker and designing something a little less imposing and am targeting a panel that looks like these:



* Narrow for good looks but trading off bass extension due to smaller panels. Size of the panels depends on how wide you are willing to go. 18 wide x 22 high would give you a pretty nice sized line.
* Tall so will respond as a line array. Don't know if you like the sound of line array, but its a bit like stepping into the sound stage... very enveloping. Some describe it like listening to a giant set of headphones but I think its much better because the sound stage is in front of you. To me they sound even better if you can listen inside the focused array and a taller line will allow you to listen and further distances. I currently have to pull my panels within 5-6 feet of me.
* If you have an EQ/DSPMini you could flatten the response and boost the low frequencies. I won't listen to a panel anymore unless its EQed flat and the jagged bass response of light weight materials like XPS is smoothed.
* They should be more sensitive - 93-94dB I would say. Dynamics should be even better. Won't take much to drive these.
* We can't make them quiet that thin I would say but if we chamfer the back side of the frames they should look very thin and dang good lookin'.

Man, I'd go with the Ultras if its sound quality your after. The Thrusters sound very good but the Ultra's have really opened up and are making some really nice music for me right now. Was up to 3 am last night listening... just couldn't pull myself away. Good stuff.

Looking forward to your impressions of DML panel sound.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Maybe I missed it somewhere but which thickness of XPS is best for a 30x24 panel?

Jeff... in Appleton... howdy neighbor!

I use 1 in. thick XPS. You can build 2 sets of panels from a 4x8 sheet. I have Home Depot cut them for me. 10 minutes and HD and $15 later your in your car and headed for home. A 40 minute sanding job and your ready for the panel treatment. All said.. in less than an hour and a half you will be listening to your first set of DMLs. Its fun and a great way to try DML panel sound for little time and money. DIY at its best.

If you want to swing by for a quick listen feel free. We will be out and about with the boys soccer but will be in the Valley all weekend.

I also have a set of new Ultra's around if you want to build them this weekend. Or you could take my Thruster panels home with you to give them a listen first. Also have a set of Thrusters on birch ply yet that I haven't dismantled. But the ply panels absolutely need EQ to sound good. Even the 1/8 in thick ply has muted highs so I would waste your time with these unless you have a means EQ.

Just let me know.. always willing to help a brother out.

Rich

[rmeinke]

Re: DIY Flat Panel Speaker Love

Even a thicker panel frame looks nice. Even as wide as these are, I think they would look good in room. And because the panels are so light, I had intended to setup and tear down and move them to a different space to store when not in use so if that would work for others you could build a panel that would not need a sub for most music.

[stinems]

Re: DIY Flat Panel Speaker Love

I have a terrible itch to wall mount these panels. Put it at the front of a 5" deep frame around it, filled with cotton insulation to at least somewhat kill the backwave.

One of the things I want to mess about with is whether there is a way to optimally dampen the edge of the panels, or if its better to minimize constraints (ie, boundary conditions) so that the panel is maximally "free" to vibrate according to its forcing function.

I'm starting out cheap with four of the DAEX25FHE units currently in transit to my doorstep. Proof of concept phase.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Funny, that was my intended purpose of my first DML panels using the same exciter. Bought the 2 - 2ft. x 2ft. Owens Corning "Handy Panels" at Lowes and was going to build as shallow a frame as possible with room or a little poly sheet for mounting behind my flat screen.

Didn't have any high expectations but thought that they HAD to sound better than my crappy TV audio... and here I sit 3 + months later still propped up on chairs and resting on socks.

I have not spent much time with suspension to be honest. Most prefer the panels as free floating as possible but modeling suggest that to low freq. response is smoother with "full rolled" suspension which I have interpreted to mean that there are small contact points around the entire edge to damp and hold the panel in place. When I do decide to build frames I want to try that as a suspension method but still wondering how it will sound compared to free floating... only one way to find out.

Too bad you didn't order the Ultra's... they are really at a different level than the DAEX25FHE. But as you said... its a cheap way to prove them out and get some listening time with DML panels.

Good luck with the build!