DIY Flat Panel Speaker Love

[Fshow]

Re: DIY Flat Panel Speaker Love

Hi Guys

I found it useful to run a sine wave generator, slowly ramping up at 1 hz steps starting at 30 hz. It makes it easy to see where the panels misbehave. I remember thinking I would have to crossover at 300 or 400 hz in order to eliminate panel problems, but it confess I don't remember which panel size or variation, I was running at the time. Building a frame and adding a spline to mount the exciter is what I ended up with to control resonances.

Fred

[DarKWerX]

Re: DIY Flat Panel Speaker Love

Hi guys, thanks for hosting this thread. I feel like I already know many of you from posts @ audiocircle & diyaudio, although I've never been an active poster at either (have spent much time lurking @ both as well as here though).

You might be interested in knowing something I've found while experimenting with Sedge's magic PVA coating. It seems that standard printer ink (likely a diluted India ink, as it was black I tested) takes very well to the PVA. I did samples with both Elmer's Glue-All & Titebond III. It should work on similar PVA types and both foam types, albeit EPS will be more difficult to achieve a consistent finish with it's uneven surface with it's accompanying voids.

However, don't use it with raw foam panels, it *the ink* will never dry. Hope that helps some of you with the WAF issues :p

...The current panels that have built are 24 x 60 foam panels treated per you and others. The only difference is I have glued a wood frame to the perimeter and have the exciter mounted to a spline. This makes the panels truely full range with deep base and no panel ratting. I am sure your first thought is this will kill the sound. To me this is not the case. [ATTACH=CONFIG]55593[/ATTACH][ATTACH=CONFIG]55594[/ATTACH][ATTACH=CONFIG]55595[/ATTACH]I do have to equalize some but both the bass and treble are present. My previous panels were 40 x 60 black foam board and I tried countless ways to support the perimeter, but in the end I had to fix the edge directly to the frame.

Fred

[ATTACH=CONFIG]55592[/ATTACH]

Hi Fred, I'd had parallel thoughts on this very same style of attachment & happened across this thread whilst researching the subject for a new build. I noticed what appears to be a curvature in the width your panels, leading me to wonder if there was a specific reason you compressed the XPS that much? Or ofc, if it's simply an optical illusion in the photo?


Thanks for your advice,
Scott

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hello Scott and welcome to the thread my friend!

Thanks for reporting back on Sedge's ink treatment... that is fantastic to know it is indeed an option to color the ugly pink panels and make it possibly to successfully conceal the panels behind grill cloth. Yeah!! Super sweet news!!

[Fshow]

Re: DIY Flat Panel Speaker Love

Hi guys, thanks for hosting this thread. I feel like I already know many of you from posts @ audiocircle & diyaudio, although I've never been an active poster at either (have spent much time lurking @ both as well as here though).

You might be interested in knowing something I've found while experimenting with Sedge's magic PVA coating. It seems that standard printer ink (likely a diluted India ink, as it was black I tested) takes very well to the PVA. I did samples with both Elmer's Glue-All & Titebond III. It should work on similar PVA types and both foam types, albeit EPS will be more difficult to achieve a consistent finish with it's uneven surface with it's accompanying voids.

However, don't use it with raw foam panels, it *the ink* will never dry. Hope that helps some of you with the WAF issues :p



Hi Fred, I'd had parallel thoughts on this very same style of attachment & happened across this thread whilst researching the subject for a new build. I noticed what appears to be a curvature in the width your panels, leading me to wonder if there was a specific reason you compressed the XPS that much? Or ofc, if it's simply an optical illusion in the photo?



Thanks for your advice,
Scott

Hi Scott

The panels are flat, at least that is what I tried to do. On panel has a slight bend in the bottom corner but it doesn't seem to cause any problem, (there isn't much movement on the panels especially at the edges.). The panels are rattle free but you do have to equalize, I have been using the equalizer imbedded in the music player, Foobar or ITunes. To me they sound wonderful, especially when I connected my T amp directly to a battery. But I don't have golden ears, really. I would not like to talk someone into building them and then being disappointed. All I can say is, I am not disappointed, and I didn't notice a decrease in detail from when the panels were free floating. I did notice much better bass and no rattles.

Fred

[DarKWerX]

Re: DIY Flat Panel Speaker Love

Hello Scott and welcome to the thread my friend!

Thanks for reporting back on Sedge's ink treatment... that is fantastic to know it is indeed an option to color the ugly pink panels and make it possibly to successfully conceal the panels behind grill cloth. Yeah!! Super sweet news!!

Hi Rich,

Glad to be able to give something back to the community, & many thanks for the welcome! :D Yeah, I was just tooling around a few days ago after receiving my Ultra's and waiting for the rain to subside so I could go and pickup some MDF & Birch for my project, when it occurred to me. Thought I'd share my findings w/ everyone, it's certainly an improvement over the standard fare colors, no doubt.

Just a general question from that which I've seen mentioned in a few of the threads I could dig up on the net. Has anyone actually used a laminate over the foam? The reason I ask is that I have a decent amount of African Rosewood (a figured, part quilted, part pommele Sapele. A blistered burl pattern to explain, so no one has to go to a dictionary for the terms) that I was considering for the face of the panel for a decorative touch. Here's a pic, although not exactly what mine looks like, it's quite similar.



On the other hand, I would certainly not like to ruin what is some pretty pricey AAA grade exotic hardwood veneer in a possibly fruitless venture if it's an unknown factor... :o

Hi Scott

The panels are flat, at least that is what I tried to do. On panel has a slight bend in the bottom corner but it doesn't seem to cause any problem, (there isn't much movement on the panels especially at the edges.). The panels are rattle free but you do have to equalize, I have been using the equalizer imbedded in the music player, Foobar or ITunes. To me they sound wonderful, especially when I connected my T amp directly to a battery. But I don't have golden ears, really. I would not like to talk someone into building them and then being disappointed. All I can say is, I am not disappointed, and I didn't notice a decrease in detail from when the panels were free floating. I did notice much better bass and no rattles.

Fred

Thanks Fred, I sincerely appreciate the input.


Heh, no worries about talking me into anything, lol. I've been tooling around with exciters for quite a while. This would be my 12th set so I know roughly what to expect, & my main concerns are directed to the Ultra's reliability which seems a bit iffy from all indications around the web. I've toyed around with constraining the corners (only) before, and it improved the looseness of the lower octaves a fair bit at the expense of a slight bit of sensitivity. A consequence I'll suffer happily for a bit more bottom end accuracy so I can crossover at a lower octave to a sub more handily w/o imaging smear. ;)

I'm no audiophool golden ear either, although I did stay at a Holiday Inn last night. J/k :D

High quality constant Q hardware (or software) subtractive EQ'ing doesn't bother me a whit, unlike some, and my main source for listening is mostly Foobar as well. I can hear gasps from the purists of "commoner DD" turntables at my *other* main source, a pair of SL1200 Mk 2's through N.I.'s Traktor Scratch 2. They freak even more when they see slipmat's on the platters, lol. So yeah, nothing but grounded earthly comments from me, even though I do like Audyn Plus (& better) caps sound (which I'm using in these).


I do enjoy a warmer sound with little more air & bit more full bottom end, so the plan is:

- Using the exciters at near to full range, worst case scenario I may high pass them @ 45hz as I'm going with a slightly smaller panel, roughly 50% the size of yours due to room constraints.

- Enhancing the top end sparkle with the Dayton/Tianle mini AMT's. Crossed 4th order @ 9k for supertweeter duty.

- Finally, I'm looking into a Ripole enclosure (somewhat similar Slot Loaded OB concept, but smaller in physical size than Nelson Pass's SLOB. No monolithic monstrous wall with Ripole. The advantage of Ripole's are the ability to play one full octave lower than Fs, but they're power hungry as a consequence) for a pair of subwoofers to pull up the lowest octaves up to +/- 70Hz. I enjoy pipe organs, & electronic music too, so it would be nice to reach the fundamental freqs of the largest pipe organs.



I know this requirement of mine contradicts many's feeling on the full range panels, hence my apprehension at posting such elsewhere. However, the other components/construction were chosen as much for their emission speed/quickness similarity to exciters & electrostat's to match as closely as possible in hopes of solving some of the very few (and small) issues I have with my other exciter projects. I hate phase problems, lol. ;)

[Fshow]

Re: DIY Flat Panel Speaker Love

Hi Rich,

Glad to be able to give something back to the community, & many thanks for the welcome! :D Yeah, I was just tooling around a few days ago after receiving my Ultra's and waiting for the rain to subside so I could go and pickup some MDF & Birch for my project, when it occurred to me. Thought I'd share my findings w/ everyone, it's certainly an improvement over the standard fare colors, no doubt.
A
Just a general question from that which I've seen mentioned in a few of the threads I could dig up on the net. Has anyone actually used a laminate over the foam? The reason I ask is that I have a decent amount of African Rosewood (a figured, part quilted, part pommele Sapele. A blistered burl pattern to explain, so no one has to go to a dictionary for the terms) that I was considering for the face of the panel for a decorative touch. Here's a pic, although not exactly what mine looks like, it's quite similar.

[ATTACH=CONFIG]56192[/ATTACH]

On the other hand, I would certainly not like to ruin what is some pretty pricey AAA grade exotic hardwood veneer in a possibly fruitless venturewwwww if it's an unknown factor... :o


Q



Thanks Fred, I sincerely appreciate the input.


Heh, no worries about talking me into anything, lol. I've been tooling around with exciters for quite a while. This would be my 12th set so I know roughly what to expect, & my main concerns are directed to the Ultra's reliability which seems a bit iffy from all indications around the web. I've toyed around with constraining the corners (only) before, and it improved the looseness of the lower octaves a fair bit at the expense of a slight bit of sensitivity. A consequence I'll suffer happily for a bit more bottom end accuracy so I can crossover at a lower octave to a sub more handily w/o imaging smear. ;)

I'm no audiophool golden ear either, although I did stay at a Holiday Inn last night. J/k :D

High quality constant Q hardware (or software) subtractive EQ'ing doesn't bother me a whit, unlike some, and my main source for listening is mostly Foobar as well. I can hear gasps from the purists of "commoner DD" turntables at my *other* main source, a pair of SL1200 Mk 2's through N.I.'s Traktor Scratch 2. They freak even more when they see slipmat's on the platters, lol. So yeah, nothing but grounded earthly comments from me, even though I do like Audyn Plus (& better) caps sound (which I'm using in these).


I do enjoy a warmer sound with little more air & bit more full bottom end, so the plan is:

- Using the exciters at near to full range, worst case scenario I may high pass them @ 45hz as I'm going with a slightly smaller panel, roughly 50% the size of yours due to room constraints.

- Enhancing the top end sparkle with the Dayton/Tianle mini AMT's. Crossed 4th order @ 9k for supertweeter duty.

- Finally, I'm looking into a Ripole enclosure (somewhat similar Slot Loaded OB concept, but smaller in physical size than Nelson Pass's SLOB. No monolithic monstrous wall with Ripole. The advantage of Ripole's are the ability to play one full octave lower than Fs, but they're power hungry as a consequence) for a pair of subwoofers to pull up the lowest octaves up to +/- 70Hz. I enjoy pipe organs, & electronic music too, so it would be nice to reach the fundamental freqs of the largest pipe organs.



I know this requirement of mine contradicts many's feeling on the full range panels, hence my apprehension at posting such elsewhere. However, the other components/construction were chosen as much for their emission speed/quickness similarity to exciters & electrostat's to match as closely as possible in hopes of solving some of the very few (and small) issues I have with my other exciter projects. I hate phase problems, lol. ;)

Hi Scott

Sounds like you have a very good plan mapped out. I have never heard of Nelson Pass's GLOB. Looks interesting...years ago I quickly built a Repole type open baffle woofer. What I remember was, that it was dynamic or fast.

I also like organ music, and the low pedal notes are half the fun. Thanks for all the good information!

Fred

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hi Rich,

Glad to be able to give something back to the community, & many thanks for the welcome! :D Yeah, I was just tooling around a few days ago after receiving my Ultra's and waiting for the rain to subside so I could go and pickup some MDF & Birch for my project, when it occurred to me. Thought I'd share my findings w/ everyone, it's certainly an improvement over the standard fare colors, no doubt.

Just a general question from that which I've seen mentioned in a few of the threads I could dig up on the net. Has anyone actually used a laminate over the foam? The reason I ask is that I have a decent amount of African Rosewood (a figured, part quilted, part pommele Sapele. A blistered burl pattern to explain, so no one has to go to a dictionary for the terms) that I was considering for the face of the panel for a decorative touch. Here's a pic, although not exactly what mine looks like, it's quite similar.

[ATTACH=CONFIG]56192[/ATTACH]

On the other hand, I would certainly not like to ruin what is some pretty pricey AAA grade exotic hardwood veneer in a possibly fruitless venture if it's an unknown factor... :o

A veneered panel would be beautiful Steve.

I don't recall if a real wood veneer has been tried over foam. However Ziggy (OP of the NXT thread over at AC) started with Gatorboard which has a real wood back and face (with a foam core). GB was displaced by other materials such as double cushioned cardboard, plywood and XPS/EPS. Now its really hard to say what might sound the best but given this, I would assume that a veneer over thin ply would sound better then veneer over XPS. Seems that folks usually strip off the paper/thin foil/etc. that typically covers a foam panel so seems to reason that you might end up in a similar situation and wishing that you hadn't used that beautiful veneer to cover foam. :-(

I have a set of 1/8" ply panels and they sound good. Not as good as XPS but respectable. I didn't spend a lot of time with them as even at 1/8" I did miss some detail that I enjoy with XPS. 1/8" is just too thin and flexible but a nice 1/32" thick veneer on one or both sides would be a solid improvement to firm up the panel I imagine!

[secret4mula]

Re: DIY Flat Panel Speaker Love

Hey Guys,
Another lurker has been dragged out of the shadows by this excellent thread

Intrigued by the DML concept and reading about all the fun you guys are having, so I went to HD and picked up some Corning XPS
to get started on building my own.

Following Rmeinke's lead I sanded down a couple of test pieces and coated them with the 50:50 mix of Elmers wood glue and h2o.
Since I am not too crazy about the pink look, I also picked up some India black drawing ink @ Michael's craft supplies and mixed it in the coating, using about 1/2 ounce in the 8oz glue/8oz h2o. Even after 2 coats, the pink could still be slightly seen and it was a medium gray. I wound up putting 3 coats on the xps, both sides, waiting about 1-2 hours between coats and now it looks black.

These test panels are going to be fairly small at 10"x18" x3/4" thick, as these were leftovers from the 2'x8' panel that will be used for the "good" pair.

Been doing a lot of reading here and at the epic thread @ audio circle, as well as learning as much as I can about the commercial DML's.
From what I can tell, Most of the commercial DML's use a frame to mount the exciters and to control the edge movement, and especially Tectonic Audio Labs' DML is very impressive. In their You Tube videos their engineers are claiming 104db 1w/1m with 90-20k +-3db.
I took a screen grab of one of the videos that shows the components that its built from.

From what is visible and what they said...
Cast Aluminum frame( looks very beefy)
Carbon fiber skin/nomex honeycomb core 40mm x 50mm 3.5-4mm thick panel (looks longer ?)
4 frame mounted exciters, centered in a tight grouping
exciters have a copper shorting ring on pole piece, voice coil looks about 25-30mm dia.
3 brass tuning weights visible on back of panel in what looks like a deliberate triangle
they have 2 models, one with 1 DML, the other with 2 of the same DML panels ( multiple panels appear to play nice together)

Cool stuff, ...yeah, Carbon fiber panels and cast aluminum frames are a little out of reach,
but I like the idea of having a frame to mount the exciter(s). Anyone have experience with multiples?

Ok, enough rambling, my little panels are ready to go, frame is next :D

Thanks for all the informative posts,
Paul

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hey Guys,
Another lurker has been dragged out of the shadows by this excellent thread

Intrigued by the DML concept and reading about all the fun you guys are having, so I went to HD and picked up some Corning XPS
to get started on building my own.

Following Rmeinke's lead I sanded down a couple of test pieces and coated them with the 50:50 mix of Elmers wood glue and h2o.
Since I am not too crazy about the pink look, I also picked up some India black drawing ink @ Michael's craft supplies and mixed it in the coating, using about 1/2 ounce in the 8oz glue/8oz h2o. Even after 2 coats, the pink could still be slightly seen and it was a medium gray. I wound up putting 3 coats on the xps, both sides, waiting about 1-2 hours between coats and now it looks black.

These test panels are going to be fairly small at 10"x18" x3/4" thick, as these were leftovers from the 2'x8' panel that will be used for the "good" pair.

Been doing a lot of reading here and at the epic thread @ audio circle, as well as learning as much as I can about the commercial DML's.
From what I can tell, Most of the commercial DML's use a frame to mount the exciters and to control the edge movement, and especially Tectonic Audio Labs' DML is very impressive. In their You Tube videos their engineers are claiming 104db 1w/1m with 90-20k +-3db.
I took a screen grab of one of the videos that shows the components that its built from.

From what is visible and what they said...
Cast Aluminum frame( looks very beefy)
Carbon fiber skin/nomex honeycomb core 40mm x 50mm 3.5-4mm thick panel (looks longer ?)
4 frame mounted exciters, centered in a tight grouping
exciters have a copper shorting ring on pole piece, voice coil looks about 25-30mm dia.
3 brass tuning weights visible on back of panel in what looks like a deliberate triangle
they have 2 models, one with 1 DML, the other with 2 of the same DML panels ( multiple panels appear to play nice together)

Cool stuff, ...yeah, Carbon fiber panels and cast aluminum frames are a little out of reach,
but I like the idea of having a frame to mount the exciter(s). Anyone have experience with multiples?

Ok, enough rambling, my little panels are ready to go, frame is next :D

Thanks for all the informative posts,
Paul

Hey Paul and welcome to the thread man!!
Lots of information here. The Podium Sound panels and especially Technonic Plates caught my attention as well. Both use a spline or frame structure to mount exciters to the panels. Multiple exciters per panel. Podium a single, all DML, panel. The Technonic Plates use a Heil AMT tweeter for high frequencies above 6K I believe. In both cases, I believe the DML honeycomb panels are attached to the frame via soft suspension... not rigidly mounted to the frame. This allows more extended and fairly smooth bass response.

As for multiple exciters, the AC thread started with the Podium model with a vertical spline holding up to 8 exciters. However over the years after much deliberate testing and listening most everyone I know settled on a single exciter per panel. As always, it is a trade off; sound quality vs. power-handling and output. As Ziggy (OP on the NXT thread at AC) stated, DML panel magic is gone when using multiple exciters. With the current crop of high shove, higher output and power-handling exciters a single panel/single exciter is very possible... especially on light-weight panel materials like EPS/XPS - sensitivity is impressive actually.

Similarly, over years of experimenting and listening, the spline mounting gave way to free mounting a single exciter to a panel. Given that, I personally never tried spline mounting. Podium still uses a spline and folks listened to them for years and really enjoyed them...both clustered (Monacor placement) and single exciters so no single approach is correct.

Its fun to experiment Paul and to find the sound quality and trade-offs that best meet your criteria! But the basic and most used recipe thus far is:
- Some type of frame and suspension is required for smoothing low freq. response. Some report that placing a panel within a frame removes some of the DML magic. He cut off 1 side of the frame and seemed to be happier with that. Many attach the panel to the frame via Velcro at various points on the panel/frame... typically with the panel mounted face to face on the frame but also often fully framed with Velcro, thin foam material, stretchy bands, etc. with minimal suspension.
- Single free mounted exciter to a single panel for more DML panel magic.
- 1/4" wood ply sounds quite good but with reduced output. HF roll-off begins around 8K on a 2x4ft. panel. Suspension is less critical as there is little panel flex so low freq. response is smooth and extended.
- 3/4" - 1" EPS (high density best) and XPS appears to have the broadest frequency response with very good high and low freq. response. Panels must be sanded and treated. 1:1 ration of PVS glue and water is easy and cheap. Shellac has also been used (thinning it would be best). Round corners and edges. Suspension is needed to smooth low freq. response. Unless fully suspended, the low frequencies still require some help to smooth the low freq. response. Sub or EQ appear to work well. I personally think EQ is REQUIRED to smooth and tailor the entire response for the best balance and fidelity.
- Panels should be fairly close to square. The golden ration is mentioned in the NXT patent and other white papers. This generates the most nodes on the panel. **
- Monacor placement of exciters is best. **

** The PE "Understanding Exciters" paper is concise and covers the basics very well.

Probably more to add, but thought it would be good to start to pull together more "best practices". Some might not agree with all the above, but this does seem to be what most builders settled on over the years... right or wrong. Will likely be the best place to start and tweak from there with room for experimentation!

Even on this thread, from rigid suspension and spline mounting to near freely suspended and mounted all of the panels sound amazing!! So have fun and just enjoy the DML panel magic!!

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hey Guys,
Another lurker has been dragged out of the shadows by this excellent thread

Intrigued by the DML concept and reading about all the fun you guys are having, so I went to HD and picked up some Corning XPS
to get started on building my own.

Following Rmeinke's lead I sanded down a couple of test pieces and coated them with the 50:50 mix of Elmers wood glue and h2o.
Since I am not too crazy about the pink look, I also picked up some India black drawing ink @ Michael's craft supplies and mixed it in the coating, using about 1/2 ounce in the 8oz glue/8oz h2o. Even after 2 coats, the pink could still be slightly seen and it was a medium gray. I wound up putting 3 coats on the xps, both sides, waiting about 1-2 hours between coats and now it looks black.

These test panels are going to be fairly small at 10"x18" x3/4" thick, as these were leftovers from the 2'x8' panel that will be used for the "good" pair.

Been doing a lot of reading here and at the epic thread @ audio circle, as well as learning as much as I can about the commercial DML's.
From what I can tell, Most of the commercial DML's use a frame to mount the exciters and to control the edge movement, and especially Tectonic Audio Labs' DML is very impressive. In their You Tube videos their engineers are claiming 104db 1w/1m with 90-20k +-3db.
I took a screen grab of one of the videos that shows the components that its built from.

From what is visible and what they said...
Cast Aluminum frame( looks very beefy)
Carbon fiber skin/nomex honeycomb core 40mm x 50mm 3.5-4mm thick panel (looks longer ?)
4 frame mounted exciters, centered in a tight grouping
exciters have a copper shorting ring on pole piece, voice coil looks about 25-30mm dia.
3 brass tuning weights visible on back of panel in what looks like a deliberate triangle
they have 2 models, one with 1 DML, the other with 2 of the same DML panels ( multiple panels appear to play nice together)

Cool stuff, ...yeah, Carbon fiber panels and cast aluminum frames are a little out of reach,
but I like the idea of having a frame to mount the exciter(s). Anyone have experience with multiples?

Ok, enough rambling, my little panels are ready to go, frame is next :D

Thanks for all the informative posts,
Paul

Oh, I was gunna say too Paul. I don't know if I would put the treatment on the rounded edges. I have to think that the hard treatment will cause sound waves to be reflected back into the panel. Will it impact SQ significantly... no... but might want to just mix the ink/dye with just water to first treat the panel and edges. Then mix with the PVA|water treatment the last coat or 2.

Sedge... who discovered the magic treatment suggests a single treatment to front and back but I thought 2 coats back 1 front reduced panel noise better and also sounded more detailed and clear to me. But I can see how adding too many treatments might reduce HF response and detail at some point... just don't know where that point is.

Like I stated in an recent post, most folks tend to strip off even very light and thin panel coverings like alum. foil from EPS/XPS panels. So there is a point of diminishing return and negative effects of too much surface treatment.

Have fun man!

[secret4mula]

Re: DIY Flat Panel Speaker Love

Hey Rich,
Thanks for the warm welcome! and appreciate all the tips.
Been reading my buttt off for the last couple days, and I think its starting to sink in a little

I got my frames done and was able to join them to the xps panels. Since Mounting the panels directly to the frames is frowned upon, a suspension or surround was called for, so I am trying out something a little different. I used pipe insulating foam, normally used for keeping pipes from freezing, cut in half lengthwise, and glued to the edges of the panel and frame. I read where you were rounding off your edges, but with the way I am mounting the suspension, I needed straight edges. Another benefit is that the substantial radius to the half round foam should cut down the edge diffraction. This has worked well on my diy open baffle line arrays.

On the coating, yeah, i have read anywhere from 1 to 5, but no real data as to what is optimal. Looking at tectonic, and not sure about podium, they are using a carbon fiber "skin" on both sides that is substantially thicker than a couple coats of glue. Goebel (spelling?) has a exotic wood sandwich that is also coated, possibly shellac, but thickness unknown. From the tectonic videos, their panel is very stiff, and "rings" when struck.

Just for fun, I also coated some of the cheap foamboard with the mix to get a better feel for what increasing layers do. Striking it with its original paper backing, its relatively resistant to bending, and sound a little dead. After peeling the paper off both sides it lost its strength and became very bendy and very dead sounding. I applied 1 coat and it was stronger, and more resonant, but still not as strong as the paper backing. After 2 coats, much better, but still not as strong and still bendy. Still could see white thru the gray coating. After 3 coats it was way stronger and resists bending much more than the paper backing. It has a nice sound to it and for a smaller panel i'm thinking this could work...maybe the next experiment, lol.
That's why I settled on 3 coats for these xps panels, front and back, as they really "came alive".

ok, back to work, gotta build stands, and make the electrical connections. I'm hoping to fire 'em up tonite :D

[DarKWerX]

Re: DIY Flat Panel Speaker Love

Hi Scott

Sounds like you have a very good plan mapped out. I have never heard of Nelson Pass's GLOB. Looks interesting...years ago I quickly built a Repole type open baffle woofer. What I remember was, that it was dynamic or fast.

I also like organ music, and the low pedal notes are half the fun. Thanks for all the good information!

Fred

Thanks Fred, & thanks for your input, especially where the ripole is concerned. That's an area where my knowledge is limited, having come from a great many sealed & vented designs. This will be my first large scale venture into OB subwoofers & I'm looking forward to it.

A veneered panel would be beautiful Steve.

I don't recall if a real wood veneer has been tried over foam. However Ziggy (OP of the NXT thread over at AC) started with Gatorboard which has a real wood back and face. GB was displaced by other materials such as double cushioned cardboard, plywood and XPS/EPS. Now its really hard to say what might sound the best but given this, I would assume that a veneer over thin ply would sound better then veneer over XPS. Seems that folks typically strip off the paper/thin foil/etc. that typically covers a foam panel so seems to reason that you might end up in a similar situation and wishing that you hadn't used that beautiful veneer to cover foam. :-(

Hi Rich, those were my worries as well with the veneer. I'll probably pick up some lesser quality veneer to experiment with in the future, but I think a tried and true method would be a better approach at this point. I do however, intend to stick with the XPS on this project for the higher quality sound. ;)

Mostly because I keep a rather large amount of foam around for one of my other hobbies, diy Halloween & Christmas stuff. I've probably inhaled as much foam dust/pellets as your average Dow/Owens Corning employee over the years. :p

Hey Guys,
Another lurker has been dragged out of the shadows by this excellent thread

Intrigued by the DML concept and reading about all the fun you guys are having, so I went to HD and picked up some Corning XPS
to get started on building my own.

Hi Paul, welcome to the party! Nice job with the panels, looking forward to seeing more of your project soon. Looks great! :D Now that I'm back in town, I need to get back to work on mine in earnest, lest I see someone else make my idea reality before I do. Lol! C'est la vie. :p




Just an FYI for all who read the thread:

I had the best success with applying the ink after the PVA/H2O mixture. Seems to allow the ink to dry more quickly in my experience, albeit I didn't use a source of heat (heatgun or hairdryer), and it prevents any spots where the PVA didn't get full coverage. The ink won't dry with the ink I used specifically if applied to untreated foam. That may ofc vary with differing types of inks, but I wouldn't get to excited and apply w/o testing with a different ink.


Cheers,
Scott

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hey Rich,
Thanks for the warm welcome! and appreciate all the tips.
Been reading my buttt off for the last couple days, and I think its starting to sink in a little

I got my frames done and was able to join them to the xps panels. Since Mounting the panels directly to the frames is frowned upon, a suspension or surround was called for, so I am trying out something a little different. I used pipe insulating foam, normally used for keeping pipes from freezing, cut in half lengthwise, and glued to the edges of the panel and frame. I read where you were rounding off your edges, but with the way I am mounting the suspension, I needed straight edges. Another benefit is that the substantial radius to the half round foam should cut down the edge diffraction. This has worked well on my diy open baffle line arrays.

On the coating, yeah, i have read anywhere from 1 to 5, but no real data as to what is optimal. Looking at tectonic, and not sure about podium, they are using a carbon fiber "skin" on both sides that is substantially thicker than a couple coats of glue. Goebel (spelling?) has a exotic wood sandwich that is also coated, possibly shellac, but thickness unknown. From the tectonic videos, their panel is very stiff, and "rings" when struck.

Just for fun, I also coated some of the cheap foamboard with the mix to get a better feel for what increasing layers do. Striking it with its original paper backing, its relatively resistant to bending, and sound a little dead. After peeling the paper off both sides it lost its strength and became very bendy and very dead sounding. I applied 1 coat and it was stronger, and more resonant, but still not as strong as the paper backing. After 2 coats, much better, but still not as strong and still bendy. Still could see white thru the gray coating. After 3 coats it was way stronger and resists bending much more than the paper backing. It has a nice sound to it and for a smaller panel i'm thinking this could work...maybe the next experiment, lol.
That's why I settled on 3 coats for these xps panels, front and back, as they really "came alive".

ok, back to work, gotta build stands, and make the electrical connections. I'm hoping to fire 'em up tonite :D

Hey Paul! That was some quick work... cool suspension method btw, really like that a lot. Didn't mean to make you change direction on your mounting method... its fun to experiment and listen to the results. I might have to try more coats even on the 1 in thick panels... sure have enough of them around.

Funny, I did the same with the paper backed foam core. Very stiff with the paper and without its very floppy. I didn't even try to coat it or even listen once the paper was removed. I really like my small XPS panels and you can EQ the source these small panels would make an awesome desktop speaker especially with a small sub supporting the low end.

Yeah, the carbon-fiber and Nomex honeycombs panels are exotic and have all the right characteristic in regard to stiffness and self-dampening... we need to find a source for such a material!! :-)

Looking forward to hear your results!! Report back... give it some time though, its an adjustment listening to the diffused sound. A couple of days and they will really begin to make some nice music.

Good luck!!

[rmeinke]

Re: DIY Flat Panel Speaker Love

Thanks Fred, & thanks for your input, especially where the ripole is concerned. That's an area where my knowledge is limited, having come from a great many sealed & vented designs. This will be my first large scale venture into OB subwoofers & I'm looking forward to it.

Hey Scott... you are spot on here friend. An OB, SLOB or Ripole should integrate very nicely with the panels. Never built a SLOB or Ripole but I love my OB panels. They have a clarity that you don't typically find with vented or sealed enclosures. I'd like a full-range panel but I think its asking a bit much unless you have room for a set of very large panels. ON is more practical and the QUALITY of bass is better than the panels in my opinion. A SLOB or Ripole would be fantastic in this situation as you can get a get 2 drivers in a relatively small amount of space... would sit nicely below a panel(s).

Hi Rich, those were my worries as well with the veneer. I'll probably pick up some lesser quality veneer to experiment with in the future, but I think a tried and true method would be a better approach at this point. I do however, intend to stick with the XPS on this project for the higher quality sound. ;)

Mostly because I keep a rather large amount of foam around for one of my other hobbies, diy Halloween & Christmas stuff. I've probably inhaled as much foam dust/pellets as your average Dow/Owens Corning employee over the years. :p

Lol... you and these panels where made for each other then!!

[secret4mula]

Re: DIY Flat Panel Speaker Love

Hey Scott, thanks for the timely tip on the ink, without that i wouldn't have even thought to dye the glue.
Interesting that you are adding the ink after the glue is coated on. I just assumed to mix it right in, and luckily it went on ok, and dried rather quickly with no hairdryer needed. Maybe different ink?, I used Higgins brand, India black, pigment based drawing ink.

Rich, you wanted a report on some results? :D

ok, i got 'em done, and have stayed up way too late! yeah, it was a DML party

Initially I hooked them up full range, source was laptop filled with Flac files, foobar2000, 24/96 external dac, 30w/ch tube amp...

First impression, Holy Moly, these thing are LOUD. I wasn't expecting that, and second, where's the Bass? lol, I honestly didn't expect any, having some experience with dipoles. I listened for a few minutes, it was wide open, very ambient, but there was no real image, and it sounded phasy. Checked connections and Doh! In my haste to wire them up, I swapped polarity on one.
Ok, Imaging snapped into place and sounding much better. Still need Bass.... Plug in crossover, amp#2 and a set of old school acoustic suspension monkey coffins, dial in a 120 hz crossover for starters , adjust levels and lets see what these DML's can do.

Big sound stage, lots of air, very clear, better highs than I expected, actually a little too hot, will have to check with the mic another time.
Presentation is a little different. A little distant, not as close to the stage as I'm used to. It's not bad, just a different vantage point.
What is cool, is the extremely wide dispersion, as the sweet spot is now a sweet Zone. I could sit anywhere on the couch and the Acoustic Scene stayed solid, just like at a concert and moving over a couple chairs. This is way better than the Maggies can do.

I really like my small XPS panels and you can EQ the source these small panels would make an awesome desktop speaker especially with a small sub supporting the low end.

Funny you mention that, later on, I went back to 1 amp full range operation, put the speakers right in front of the couch, and in extreme near field there was good bass. A little bit of EQ to these, or maybe even smaller ones would be a real nice desktop setup.
So far, these have exceeded my expectations, and i can't wait to start on the next one.

Scott, I have been gathering parts for a ripole stack myself, as I have become spoiled by dipole Bass, but not liking the room taken over by giant panels. With the ripole it should be much more compact.

I'm just sitting here, laughing at how a hunk of insulation foam, 10 bucks of wood, and a cheap driver sound so good...