DIY Flat Panel Speaker Love

[buke9]

Re: DIY Flat Panel Speaker Love

Hey buke, just a thought - you might have an rf feedback loop on that left side. It would odd but possible. I've had a couple bass (guitar) speakers killed by that. It was the amp and replacing the amp took care of the problem. It turns out that it was transmitting some rf frequency that ANY nearby wire picked up.
Don't know if it helps but....
opa

Retiring the NAD and brought out my old Harman Kardon AV15 to run the panels.

[buke9]

Re: DIY Flat Panel Speaker Love

Something I wanted to ask for awhile now what size bayonet connectors are the exciters? I got the smallest one at the parts store and they are still a little big.

[captainjack115]

Re: DIY Flat Panel Speaker Love

Hey Jack! Nice upgrade man... I really like my Behringer. Solves many design issues all in one package and can experiment with different aspects of the design so quickly. I liked the panels au naturel but once I EQed and listened to them for some time I could not go back. Just try turning off the EQ now and tell me you prefer the sound?

Spot on about the one exciter per channel... I prefer the option to EQ, extend the low freq. and cross at different points so appreciate the multiple panel approach yet maintaining the pure 1 exciter to 1 panel configuration. And while a single 12x12 panel is crystal clear and "fun" to listen too (esp. once EQed and extended down to 110Hz) and I could be more than perfectly happy with this combined with a sub there is still value (if you can integrate into the room well enough) in the thin and tall panel array (4 panels like what you have). Listening within the focused array is like walking *into* the venue... anyone who has listened to a well done line array will know what I'm talking about.

But like I said... that is IF you can integrate the array into your room. My dedicated listening room is pretty small and think that if I *had* to pick a single panel it might be a small panel and open baffle bass bin combo. In my listening room I would probably go with a larger line array.

To the Ultras and Thrusters, I had the same hollow or maybe "distant" sound quality with the Ultra's on think ply and preferred the Thrusters on ply. They are not as good on heavier or probably even with tightly/well damped suspension. So I would venture and guess that the Coroplast is light in general terms but compared to XPS they are may be a few times heavier... wish I had a small, accurate scale to have the actual weights so we could begin to dimension when the preference goes from Ultra to Thruster. I've only listened to Ultra's on panels 24"x30" panels or smaller (down to 12 x 14.5" roughly) so can not really gauge this well yet.

Since you have the Ultra's you should build a XPS panel!

OHHHhhhhh, and did anyone see the new Dayton Audio DAEX32Q-8 Dual Steel Spring Balanced 32mm Exciter 40W 8 Ohm exciters??? Could be a perfect solution to a 2 panel array. More sensitive once wired in parallel... hope they sound as good as the Thrusters... would be an excellent addition and option for arrays!

I'm impressed with the DEQ2496, the D/A converter is very quiet, running directly into the power amp. I have switched it in/out and it's amazing the effect it has on the ears.Needless to say I like what I hear.

I feel I've made a poor choice on my sub-woofers. About two years ago I bought a pair of SVS 12" sealed units, I've never been happy with them. They're kind of "peaky" in the 35 to 40hz range, not smooth and extended. At $1100 a pair I'm stuck with them, too much of a hassle to sell on ebay. I like the DEQ2496 so much I'm actually considering buying a second unit to flatten out the bass.
Best bass I ever had was the 4 Dayton Titanic’s in a wall as an infinite baffle, that' never going to happen again since moving to a smaller house.

Line arrays are great if you have the room, I've done them with cone speakers, also had a pair of B&G RD-75 line source drivers. With all that I still never had the "magic" of the DML sound.

Somewhere down the line, I'd like to get my hands on some XPS and put the Ultras to good use.

OK, whose gunna be next to try the new DAEX32Q-8?

Jack

[buke9]

Re: DIY Flat Panel Speaker Love

Just wondering if putting support on the exciter via a spine support would help with the bass rattle I get ( don't know what else to call it ) when a strong low freq signal hits the panels.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Just wondering if putting support on the exciter via a spine support would help with the bass rattle I get ( don't know what else to call it ) when a strong low freq signal hits the panels.

Hey Buke! What size panel and suspension are you using now? Imagine you have a large panel and in need of more suspension to properly dampen the panel.

[rmeinke]

Re: DIY Flat Panel Speaker Love

OK, whose gunna be next to try the new DAEX32Q-8?

Oh, oh... me, me!!

Hoping to get my hands on some soon along with a few bass shakers for a full size 4x8 bass panel.

[buke9]

Re: DIY Flat Panel Speaker Love

Hey Buke! What size panel and suspension are you using now? Imagine you have a large panel and in need of more suspension to properly dampen the panel.

I dampened it as little as possible . The panel is 24 x 30 . Gonna try the stiffer foam this time and see what happens.

[rmeinke]

Re: DIY Flat Panel Speaker Love

I dampened it as little as possible . The panel is 24 x 30 . Gonna try the stiffer foam this time and see what happens.

Hey Buke! I would try adding more suspension points so you get more damping across the panel.

If you can recreate the rattle easily, play that track and put a finger in a location that might be a good place to add more foam suspension. I would start along the longest panel edge that is free of suspension then add a small piece of foam where needed. If you are using small pieces of foam for light suspension, it should not impact sound quality in any way.

How are they sounding? Are you adjusting to the presentation of the DML panels?

[vega406]

Re: DIY Flat Panel Speaker Love

Interesting stuff going on in this thread!

How do you think a panel would sound with lets say a 6" frame around it placed against a wall? I envision some sound absorbing material placed furthest back by the wall, the panel suspended by some foam suspension placed 1 to 2 small places per side with the XPS toward the front part of the frame and furthest from the wall. With a setup like this, you could possibly throw some acoustically transparent cloth across this and have it printed on just like the DIY sound absorption panels for sound treatments? Do you think the panels would lose their "magic"? I would just quick try myself to test, but a newborn is making it difficult to get the projects I actually need to get done, done lol.

http://www.avsforum.com/forum/19-ded...els-cheap.html

[buke9]

Re: DIY Flat Panel Speaker Love

Hey Buke! I would try adding more suspension points so you get more damping across the panel.

If you can recreate the rattle easily, play that track and put a finger in a location that might be a good place to add more foam suspension. I would start along the longest panel edge that is free of suspension then add a small piece of foam where needed. If you are using small pieces of foam for light suspension, it should not impact sound quality in any way.

How are they sounding? Are you adjusting to the presentation of the DML panels?

I'll try adding a couple more pieces of foam and see what happens. I am liking the sound for more acoustic music than hard rock stuff. They hate Black Sabbath but love America. I still think I am going to sand them down again and try and try a extra coat or two. When I get time I'll give it a try. I just started my first box speaker build. Needed a new center speaker so I thought why not build my own. See what you guys started ; ).

[rmeinke]

Re: DIY Flat Panel Speaker Love

That-A-boyeee!!! Its fun stuff Buke... addicting actually!!

Yeah, I don't enjoy rock from the magic panels. But I feel the same about other flat panel speakers and why I had not choosen other panels in the past.

But for acoustic and any live music the DML panels are amazing. They don't sound like speakers... just music...

[captainjack115]

Re: DIY Flat Panel Speaker Love

I made a side by side comparison of the coraplast panels and my MMG's.

For over-all sound qualities, the MMG's are hard to beat, I had them crossed over at 200 hz the same as the coraplast panels. The big difference of course is the magic spaciousness that is DML.
As it turns out, I'm not using the auto-eq feature of the Behringer DEQ 2496, nor fussing with the individual frequency correction of the rta, I got better results using the parametric function.
In my case I found pulling down a center frequency around 700 hz works quite nicely. The highs are there, they just need to have the mid range pulled down to meet them.
The coraplast panels do have repeatable results, given that they aren't coated with anything. I'm still in the same boat with everyone else over suspension issues.

On a lower note. (Sorry for the pun). I bought another DEQ 2496 for my SVS subs. It was a worthwhile investment to tame the peaky 50/60's and extend the bottom to 20 hz. Still not the fantastic bass I had with my infinite baffle system, but respectably doable. Seems a lot smoother.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hey Capn'! I don't use any of the auto-eq or RTA either and use only the parametric eq slots available. Auto EQing would likely make the panels sound thin and shrill sounding. I don't have the time to search and provide a link, but one of the DML papers shows the power response of a DML and it has a rising response of about 6 db through the last octave+(??). Don't quote me on the specific data but just to make a point about the panels and why simply EQing flat on axis will not result in a neutral sounding panel. EQ flat would produce a rising power response and its easily heard if you did EQ perfectly flat.

I do something very similiar to what you are going. After I EQ it "flat" (meaning the last octave is a slow gradual 6db slope) I add one last parametric setting centered around 1.1KHz, down about 1.5dB with a high Q so the dip (be nice! ) extends either side out an octave to an octave and a half. Obviously the exact setting totally change with panel size and even exciter used but this is what I currently am running on my 24x30 inch XPS panels. This sounds the best to me.

Wow, you've added alot of nice toys lately. I am going to try a Mini DSP soon. I really love my DEQ 2496 but want to see how the MiniDSP fairs. I can use it with my open baffles and DML panels to EQ and cross to a sub but smaller and hopefully less cables, etc than the Behringer. By no means getting rid of the Behringer as its so powerful and quick to prototype and shape the audio signal. I've ditched passive cross-overs... just so costly now a today's. Nothing against them its just the Behringer works so very well for all the projects I throw at it!

[captainjack115]

Re: DIY Flat Panel Speaker Love

Hey Capn'! I don't use any of the auto-eq or RTA either and use only the parametric eq slots available. Auto EQing would likely make the panels sound thin and shrill sounding. I don't have the time to search and provide a link, but one of the DML papers shows the power response of a DML and it has a rising response of about 6 db through the last octave+(??). Don't quote me on the specific data but just to make a point about the panels and why simply EQing flat on axis will not result in a neutral sounding panel. EQ flat would produce a rising power response and its easily heard if you did EQ perfectly flat.

After playing around with the rta I wish I hadn't bought the ECM 8000 microphone, the parametric is much more useful to me. I still find myself using my old rta while making adjustments.
As for full system response, I try to get resonabley flat to the lowest bass response then crank up the gain on the subs until it sounds right to my ears. After all is said and done if it doesn't sound good to the ear, what's the point of it all? I really like the DEQ 2496 it does a ton of useful things and it's really quiet. I did have a ground loop situation when I first hooked it into my system, but a plug adapter took care of things. Not to put down the technology of DML's, but I swear I could stick an exciter on just about anything and the DEQ 2496 will make it sound good.

I talked to a friend on the phone a few days ago, we had lost contact a few years ago. He's been a manufacturer of many things in audio. I won't mention his name without permission, but I did tell him that I've been on this site, so he may deside to jump in on his own. I think it's safe to say that he currently makes high end cables.
Anyway, he tells me that he had designed and manufactured a DML system using stretched Mylar. The exciters were made in house and very robust. I need to talk to him more on how it operates as a DML as we know it.

Jack

[rmeinke]

Re: DIY Flat Panel Speaker Love

Heck, using the 8000 microphone with your RTA or software like REW is totally cool Jack. I use my OmniMic setup to dial in a "flat" response. The FR with XPS DML panels is not the smoothest freq. response in the world so any option that brings a smoother FR is all totally fair play in my opinion... how ever it happens!

Hmmmm... I recall someone mentioning a design of stretched Mylar diaphragm with a conventional voice coin attached. Interesting for sure but I wonder if it would really be classified as a DML... seems to me that this configuration would be more similar to an electrostatic or FR ribbon but driven from a single point?!? The panel needs to be rigid to be able to generate nodes across the panel.

Regardless, I'd love to hear his impressions of the stretched Mylar and what the FR looked like.

Cheers!
Rich