DIY Flat Panel Speaker Love

[buke9]

Re: DIY Flat Panel Speaker Love

Just got the ultras in today and couldn't wait for the other thruster to come in so I popped off the dead thruster and stuck the ultra in it's place (have not heard the panels in stereo yet) OMG. I know I'm running two different drivers but had to hear it in stereo. Just sitting on the floor leaned up against my LSi15's with padding behind them they sound pretty damn good. They are just a little bright to me for somethings but for others not too much. I find these like some music more than others. This might change when mounted in some frames. They love acoustic music for the most part but hates Black Sabbath. After listening awhile the Ultra side is starting to make crackling sounds like I was listening to vinyl . Not on all songs just some. It might be the panel or the music. I find that certain low freqs are OK and others just buzz the panels. This might have alot to do with not being mounted. Some songs just make them move all over the place but still sound good. I just can't get over the crackle in the ultra after just listening a little more it is in every song just more than others. I need to make a few more panels and get another set to see if it is them or the panels. For the most part I love the sound . Thanks for this forum and turning me on to these it is too much fun .

[rmeinke]

Re: DIY Flat Panel Speaker Love

[QUOTE=captainjack115;2070714]

About suspension... I don't hear any ill effects from my very lightly suspended panels but think that the large rounded corners of my panels help to properly terminate the edges. But more so, I think the hollowness you mention may be a result of materials used. What material did you use Jack?

After trying a bunch of different materials, I built the 4 panel prototype a few years ago. I've continued to use the old panels from that project, the panels are made from 3mm corrugated plastic.
I never noticed a hollowness with them in the past, it could be the loose suspension via duct tape.

Today I built a frame to match the perimeter of the panel, for suspension I used double stick foam to isolate the panel from the frame. A "complete" waist of time! There was nothing near enough suspension to dampen the panel. Excitations from the panel bounced off the poorly isolated frame and right back into the panel. Strong resonance in the 125 to 250hz range, the panel so much better without that particular suspension.

One thing I "can" say about the corrugated plastic, it has plenty of high frequencies, when using a Thruster I measure flat to 16,000 (The limit of my old cheap spectrum analyser)

I took one of my old low power exciters and stuck it on to a piece of common foam core. I have to say it had pretty good bass. I compared it to one of my MMG's and I actually preferred the bass I heard coming from the foam core.

Has anyone on here actually tried the white glue mixture on a piece of foam core? Just curious!

Jack

Howdy Jack! Sounds like your busy... hoping to get a few days around home around the 4th to finally get some speaker work done myself!

If you haven't tried XPS foam with the water:PVA treatment you really owe it to yourself to try it out. This has been the material of choice over at AC for at least the last year and sounds fantastic. Round the corners and roundover the edges. If you want to hide them behind black grill cloth, after sanding off the surface layer (front and back) put black dye/ink in the panel treatment and 2 coats results in a pretty black panel easily hidden behind cloth.

Interesting, how large was the foam board that produced bass better than your MMG's?

[rmeinke]

Re: DIY Flat Panel Speaker Love

Just got the ultras in today and couldn't wait for the other thruster to come in so I popped off the dead thruster and stuck the ultra in it's place (have not heard the panels in stereo yet) OMG. I know I'm running two different drivers but had to hear it in stereo. Just sitting on the floor leaned up against my LSi15's with padding behind them they sound pretty damn good. They are just a little bright to me for somethings but for others not too much. I find these like some music more than others. This might change when mounted in some frames. They love acoustic music for the most part but hates Black Sabbath. After listening awhile the Ultra side is starting to make crackling sounds like I was listening to vinyl . Not on all songs just some. It might be the panel or the music. I find that certain low freqs are OK and others just buzz the panels. This might have alot to do with not being mounted. Some songs just make them move all over the place but still sound good. I just can't get over the crackle in the ultra after just listening a little more it is in every song just more than others. I need to make a few more panels and get another set to see if it is them or the panels. For the most part I love the sound . Thanks for this forum and turning me on to these it is too much fun .

Something is amiss here I'm afraid.. the Ultra's should be quiet. Was the panel surface flat and clean where the Ultra was reattached?

You got it right about the panels. Not great on rock... not full range anyway. Add a sub and sure, they ought to perform well.

Live music is AMAZING... jazz, acoustic, etc. is also very, very good... even prefer them over my open baffles; at least from upper bass on up.

To get the most from them get them off the floor and away from walls. They will really open up and throw a ginormous sound stage. I imagine they sound bright and bass shy playing so close to other objects. To give you some ideas... I have mine on chairs, resting on socks and leaning against the chair backs with large rubber bands... only making contact with the rubber bands. This adds just enough suspension... very light but sounds best to me.

I would play around with positioning and somehow getting them off the ground and away from walls. Have fun man!!

[captainjack115]

Re: DIY Flat Panel Speaker Love

[QUOTE=rmeinke;2070726]

Howdy Jack! Sounds like your busy... hoping to get a few days around home around the 4th to finally get some speaker work done myself!

If you haven't tried XPS foam with the water:PVA treatment you really owe it to yourself to try it out. This has been the material of choice over at AC for at least the last year and sounds fantastic. Round the corners and roundover the edges. If you want to hide them behind black grill cloth, after sanding off the surface layer (front and back) put black dye/ink in the panel treatment and 2 coats results in a pretty black panel easily hidden behind cloth.

Interesting, how large was the foam board that produced bass better than your MMG's?

I have to admit I've had a powerful curiosity about the XPS technique, I happen to have a Menards just up the road from me.
Are you treating both sides of XPS with the PVA treatment?
The guys over at AC used to do something they called the "scratch test" with panel material to see check for sensitivity, I'm wondering how XPS fairs in that department.
If it was possible I think "end cut balsa would have good sensitivity. You'd never find balsa of that size naturally, and if you did it would be very likely to break easily

My situation is that I have no work space at the moment, we're trying to clear the garage via monthly garage sales and that's been a slow go. I'm hoping to clear enough space to at least put in a work bench. When I made the frame to test the Thruster suspension I had to set up a folding table in the driveway and drag out my chop saw..............ARG!!!!
Yes rounded corners makes a huge difference in reducing bass buzz, I found that out a few years ago when playing with foam board.

The foam board I used was close to 20 inches square, I eyeballed the exciter offset. The MMG's were crossed over at 50hz, which doesn't really affect the bass coming from them. They tend to drop like a rock around 50hz anyway.

Jack

[captainjack115]

Re: DIY Flat Panel Speaker Love

Something came to mind about the voice coil connections.

I wonder if we shouldn't be more careful when sticking these exciters on the panel, pushing down on the exciter may be stressing the wires.
I had a thought that maybe we should be using some sort of thin non magnetic tool to push the rim of the exciter against the panel.

BTW, my Ultras just arrived a few minutes ago, not sure what I want to do with them just yet.

Jack

[Mayhem13]

Re: DIY Flat Panel Speaker Love

Has anyone tried some of the composite panels such as NidaCore or PLAScore? Both are comprised of individual hollow cells that offer the ability to be filled individually to shape the response. They are both very light and very rigid as well. I've used them both for boat repair/remodeling and their properties strike me as ideal for this application.

[captainjack115]

Re: DIY Flat Panel Speaker Love

Has anyone taken notice?

I just opened the package from P.E. containing the Ultra exciters and noticed the power rating is 20 watts.
On P.E.'s page for this exciter the rating is 40 watts RMS. I called P.E and talked to a tech, he asked me to take a photo of them so they can have a look. The tech remarked that it was strange and they should be 40 watts, well, that's what I thought too!

Jack

[captainjack115]

Re: DIY Flat Panel Speaker Love

Has anyone tried some of the composite panels such as NidaCore or PLAScore? Both are comprised of individual hollow cells that offer the ability to be filled individually to shape the response. They are both very light and very rigid as well. I've used them both for boat repair/remodeling and their properties strike me as ideal for this application.

Speaking for myself, it's a gamble to try a new material, especially if it's not something one can buy locally. Prices aren't outrageous for 2x4 pieces, but trying this and that can add up.
Dr. Shelley Katz used a honeycomb in his Podium loudspeaker, supposedly it performed quite well.

[buke9]

Re: DIY Flat Panel Speaker Love

Something is amiss here I'm afraid.. the Ultra's should be quiet. Was the panel surface flat and clean where the Ultra was reattached?

You got it right about the panels. Not great on rock... not full range anyway. Add a sub and sure, they ought to perform well.

Live music is AMAZING... jazz, acoustic, etc. is also very, very good... even prefer them over my open baffles; at least from upper bass on up.

To get the most from them get them off the floor and away from walls. They will really open up and throw a ginormous sound stage. I imagine they sound bright and bass shy playing so close to other objects. To give you some ideas... I have mine on chairs, resting on socks and leaning against the chair backs with large rubber bands... only making contact with the rubber bands. This adds just enough suspension... very light but sounds best to me.

I would play around with positioning and somehow getting them off the ground and away from walls. Have fun man!!

It was the floor. It seems certain freqs resonate the material in different ways. The bass is not half bad but does rattle some times. I need to get them mounted in a frame. Just have to figure how to mount them the best way. I was thinking maybe memory foam or maybe rubber like a car door seal. Just a thought I guess I can't go wrong ; )

[rmeinke]

Re: DIY Flat Panel Speaker Love

Has anyone tried some of the composite panels such as NidaCore or PLAScore? Both are comprised of individual hollow cells that offer the ability to be filled individually to shape the response. They are both very light and very rigid as well. I've used them both for boat repair/remodeling and their properties strike me as ideal for this application.

Mayhem, dang... these look very promising. Thanks for the tip. I'll have to look for these locally just to see the stiffness, damping qualities, weight, etc. I do think these are in the ball park; love to get my hands on some of this material... off to Google I go...

Thanks for the tip man!

[rmeinke]

Re: DIY Flat Panel Speaker Love

[QUOTE=captainjack115;2070767]

I have to admit I've had a powerful curiosity about the XPS technique, I happen to have a Menards just up the road from me.
Are you treating both sides of XPS with the PVA treatment?
The guys over at AC used to do something they called the "scratch test" with panel material to see check for sensitivity, I'm wondering how XPS fairs in that department.
If it was possible I think "end cut balsa would have good sensitivity. You'd never find balsa of that size naturally, and if you did it would be very likely to break easily

My situation is that I have no work space at the moment, we're trying to clear the garage via monthly garage sales and that's been a slow go. I'm hoping to clear enough space to at least put in a work bench. When I made the frame to test the Thruster suspension I had to set up a folding table in the driveway and drag out my chop saw..............ARG!!!!
Yes rounded corners makes a huge difference in reducing bass buzz, I found that out a few years ago when playing with foam board.

The foam board I used was close to 20 inches square, I eyeballed the exciter offset. The MMG's were crossed over at 50hz, which doesn't really affect the bass coming from them. They tend to drop like a rock around 50hz anyway.

Jack

Home Depot cuts it for you so I get all my XPS from them... sure makes it easier (just ask buke9!! :- ). I like the 1" the best for all but the smallest panel. I've been treating both sides with 2 coats. Using a hair drier to make the process so faster. I can coat and dry a set of panels in less than an hour otherwise it can be a slooooow process.

Yeah, Ziggy talked about the scratch test but that isn't a valid test. The honeycomb Podium material is hard and smooth and makes no sound. The treated XPS is really what Ziggy is referring too. When you run your fingers across a treated XPS panel it is really loud and actually amplifies even a light swipe on the panels. But this doesn't make it better than the Podium composite. Balsa probably would be good but what work to build even a single panel... I'll stick with XPS for now. :-)

Interesting about the 20" panels. For their size, these DML panels really do have good extension. While the bass response is VERY uneven with my 24x30" XPS panels the large peek is at 31Hz... that's a lot of output from such a small amount of space. More suspension would flatten response and extension would be raised but would play fairly flat to the 40-45Hz range. The upper bass reminds me of my open baffles... power that makes piano and human voice sound realistic. Not boosted freq. response in the upper bass... anyone who has listened to OB will know what I mean; the bipolar response of OB and the DML panels are the likely reason. Just a joy to listen too!

[rmeinke]

Re: DIY Flat Panel Speaker Love

It was the floor. It seems certain freqs resonate the material in different ways. The bass is not half bad but does rattle some times. I need to get them mounted in a frame. Just have to figure how to mount them the best way. I was thinking maybe memory foam or maybe rubber like a car door seal. Just a thought I guess I can't go wrong ; )

Thanks for the update... glad to hear you have it sorted. If you get the panel mounted or damped you won't have rattle either. For a quick test, you can do velcro... fast and adjustable.

[Mayhem13]

Re: DIY Flat Panel Speaker Love

Mayhem, dang... these look very promising. Thanks for the tip. I'll have to look for these locally just to see the stiffness, damping qualities, weight, etc. I do think these are in the ball park; love to get my hands on some of this material... off to Google I go...

Thanks for the tip man!

http://www.merrittsupply.com/products/32038-nida-core-structural-honeycomb-plain-h8pp.aspx

Here's where I get mine. Sorry I don't have any leftovers to send you. Trust me when I say it's incredibly rigid and can easily be selectively or completely damped with ease.

[vega406]

Re: DIY Flat Panel Speaker Love

Something came to mind about the voice coil connections.

I wonder if we shouldn't be more careful when sticking these exciters on the panel, pushing down on the exciter may be stressing the wires.
I had a thought that maybe we should be using some sort of thin non magnetic tool to push the rim of the exciter against the panel.

BTW, my Ultras just arrived a few minutes ago, not sure what I want to do with them just yet.

Jack

The attachment with the tape actually unscrews from the exciter. When my one exciter went bad, I was just able to unscrew the exciter from the attachment point and put the new one on without any issue. That would allow you to attach it securely without putting undue stress on the rest of the unit. Hope this helps!

[captainjack115]

Re: DIY Flat Panel Speaker Love

The attachment with the tape actually unscrews from the exciter. When my one exciter went bad, I was just able to unscrew the exciter from the attachment point and put the new one on without any issue. That would allow you to attach it securely without putting undue stress on the rest of the unit. Hope this helps!

Yes, I saw that feature on a photo of the Ultra on P.E.'s site.

I did try giving it a turn when I first opened the box, it didn't seem to budge for me and I thought I might break it.

Jack