[OB_Newbie]

Hey Odal!!

I have had family visiting for the last week so I haven't had a chance to experiment too much - only sneaked in a little bit at lower volume late at nights

Still on my birch boards, but I have an uncut 4 x 8 XPS board standing and waiting for me to be re-skinned and cut down to more workeable size (maybe 6 x 2'). The biggest problem for me with these these boards is the pink/purple color - these would never be allowed up from the basement even if I made them smaller. This is also why I'm still trying to get the "wood" to work.

Yeah, the pink/purple color is a real bummer.  I tried spray paint on one of the panels and the solvents in the paint ate at the XPS... duh.  So have to find a paint that will work on the panel.  Going to build a frame around it anyway and hopefully the grill cloth will cover it up enough but still afraid you will be able to see the large pink panel.  Arg.

The HF is still not there, but I still need to sand them down and taper all the sides which improved a lot of my smaller boards, plus re-glue the exciters to see how much more HF this will result in. What do you think about using the same skin-method you guys are using on the EPS/XPS boards?

 There has been a lot of discussion on different material (birch, spruce,...) if you search the thread. If you do try wood, make sure the material is rigid, which may mean thicker (or supported by a frame which I haven't tried yet). The thinner 1/8 wood panels I mentioned a few posts ago flex and bend too much creating dips and spikes in the frequencies resulting in a slow and muddy sound.

I tried a new amp with a built in cross-over for fun. I set a high-pass to 3k to better evaluate the HF. That was very interesting since I couldn't really detect any vibration or movement from the board or the exciter it-self. Try it if you haven't already. So does this mean that all the HF is coming from the skin? If so this means that the HF could be done with a very thin and hard material since it will not be moving much at all. The other thing is if the vibration from the LF "ruining" the HF? Same concept as normal box speakers sounds better when dampened from vibration. You mentioned before a thre panel solution, and but what about a two panel solution where the signal is split at 3400. Just thinking out loud here, so let me know if I'm too much off.

Yeah, I had thought about using different panels best suited for high and low freq. when I first started reading this thread because it didn't seem like a single panel material could excel at both ends of the freq. spectrum.  But for now, I'm pretty happy with the full-range XPS panels so want to get them sounding the best they can then maybe see what other materials and sizes sound and if they can be used together to create a better panel.  Not sure about making a 2-way panel with a traditional passive or active xover (which could also work) but my thoughts are to run 2 panels together but possibly have the bass panel use a 1.5 inch thick XPS (for example) and a thinner, ridged panel for the high frequency panel.  The end result (hopefully) would be a bass panel with a naturally rolled off high end and a high freq. panel that has a rolled off low end.  So summed... they create a more full range panel at the extremes.  But this would take a lot of experimentation I would think and wonder if it can be done right now... just feels like we have more learning to do.  But while on the topic, there is someone over at DIYAudio that has a 2 inch thick 8 foot tall bass panel.  Crazy.  I kinda want to try that just to see what type of response you get from such a panel.  Went to HD again tonight to get more XPS and almost picked up a thick panel but the thought of have a ginormous PINK panel in the living room would be way too much.. I like to live.  Living is good.       Next time when the wife leaves town for a few days!!!!     
 

I also want to try out the "wedgie" concept with a very narrow panel phasing forward combined with a much larger panel going towards the backside at 120 degrees or the linkwitz LX521/Nao Note style panel. Again partly for visual purposes but I'm also very curious how it would sound

yeah, that would be very cool... just plan fun to play with to see how it would sound.  Do you mean to form a L by the way???   

I'm also waiting with excitment to hear if the curing of your panels improved the sound even further.

Still hard to say how much is exciter breaking in and panel curing. 

When I posted so enthusiastically about Sedge's magic coat much of it was the poor performance of the DAEX58FP actually... not an uncured panel.  When mounted to the 2x4 panel I could not believe the self-noise and generally poor performance.  At that time I thought it was an uncured panel that was responsible for the veiled sound, boomy bass, etc and that they just needed to cure much like the small panels.  I did NOT think the DAEX58FP could sound so poor on the panels.  Well, now I know... it was mainly the DAEX58FP.  As soon as I mounted the DAEX25FHE-4 exciter on a 2x4 panel I immediately heard a sound that was MUCH more similar to my small panels.  Ahhhhh.

So to conclude.  The panel treatment is excellent as has to be done... it is a clear performance improvement over a naked panel.  However a good portion of the improvement is just running in the exciter to loosen the spider/suspension.

So what has happened since... the saga continues.      The general performance has improved over the last few days but not as much as I expected. The bass is more extended on the big panels but isn't as tight and the panels are not as clear and "fast" as the smaller panels.  It might simply be the leaner bass/shape of the freq. response that lends the small panels their faster, more clear and clean sound.  I am still hearing some self noise heard on the lower piano notes and booming male voices... a resonance in the 300hz (ish) range so I'm going to give them a second coat of the magic treatment.  Hopefully that tightens up the panels a little more and provides a bit more clarity without negatively impacting the high freqs.  Don't have much time these days and when I do I want to assess how the panels are coming along.  But they are almost fully cured so don't expect any big improvements now so time for a second coat.

Looking forward to more reports from you and Ziggy as you get more time with the exciters.  I got mine today and have more panel material.  YeessssSSSS! 

Have a good night all!

[OB_Newbie]

Forgot to add something... we really ought to consider using EQ as a standard tool in the DML toolbox.  Might this not be the most practical way to increase frequency range and as overall balanced sound quality to our panels? 

going a little off topic...
I'm going to build a line array as it seems to offer many of the benefits and based on DIYers who have build them they seem incredible and *might* offer even better overall performance than our beloved panels.  Definitely for rock and the reports I've read they also sound magical for live and symphonic recordings.  EQ is required for them as well.

But these lines come with a higher price tag and substantial effort to the DIYer.  As always... compromises and personal preferences.

Here is a recent build over at PE for a line array that uses the Founec closeout driver - http://techtalk.parts-express.com/showthread.php?245410-Yet-Another-IDS-25-Clone!-25-Fountek-FE-83-drivers-in-a-line-array


   

[Odal3]

If you do, let us know how they compare. I'm happy with the fun with the panels since they sound so good. I have actually never heard OB speaker but really want to - How do your OB speakers compare with the panels and which one do you prefer?

Rock...the birch boards actually sounds great with rock. Just need a little bit sub boost on the bottom plus you need to get the panels on spikes or suspend them in the air.

If you don't mind me asking, what do you use to eq?
Yes - meant like a L shape.

[sedge]

ON_newbie
The self noise you seem to be describing is not the panel sound we have been trying to eradicate with pva,but the large panel drum effect ,which is easy to hear if you just tap your knuckle on the panel,adding another coat of pva is not really going to help hear, as you will probably need something more drastic to sort this out.
This I have found only shows itself badly on certain tracks that excite the resonance such as a loud drumming sound ,which can set off the sound.
Also If you have an 8 ft panel lets say,there is no way that that  panel is going to stop vibrating the instant you stop the music,the sound has to continue on its path through the panel like ripples on a pond ,the smaller panels will stop almost instantly to my ears anyway,on the large panels the combination of the two in the low end can make them sound a little sluggish at times ,at the moment it is probably an evil you will have to live with,smaller multiple panels per channel could solve the problem though ?
Steve

[sedge]

OB_newbie and oral3
I would be thinking more of using a water based dye not paint,the dye could be added to water or pva then applied to sanded area,it adds colour not substance to the panel.
If tuned carefully you shouldn't really need eq ,better to get it right in the first place.
Steve

[OB_Newbie]

Hello Steve!
I can't disagree with you on the getting it right the first time.  I was EQing the small panels at the beginning but wanted to here the panel and what they produced naturally.  I have not even tried to use EQ on the bigger panels yet. 

But then again, if I was using wood, preferred it over foam, and wanted a little more high frequencies I would not fault a little EQ in that situation really. 

Good tip on the dye.  Do we know if anyone has tried coloring a panel with dye/powder or paint.  I had thought about dyes/powders as well but wondered if it will accept/sink into the XPS?!?  I was thinking that it probably would not absorb much of the dye and would come away with a purple looking panel and that I might need something with more solids.  I do have a woodworking store in a town close so might have to make a purchase this weekend and give it a whirl... have enough XPS scrap these days!     Otherwise I'll probably try a waterbased paint and give that a listen as well.

Cheers!

[OB_Newbie]

ON_newbie
The self noise you seem to be describing is not the panel sound we have been trying to eradicate with pva,but the large panel drum effect ,which is easy to hear if you just tap your knuckle on the panel,adding another coat of pva is not really going to help hear, as you will probably need something more drastic to sort this out.
This I have found only shows itself badly on certain tracks that excite the resonance such as a loud drumming sound ,which can set off the sound.
Also If you have an 8 ft panel lets say,there is no way that that  panel is going to stop vibrating the instant you stop the music,the sound has to continue on its path through the panel like ripples on a pond ,the smaller panels will stop almost instantly to my ears anyway,on the large panels the combination of the two in the low end can make them sound a little sluggish at times ,at the moment it is probably an evil you will have to live with,smaller multiple panels per channel could solve the problem though ?
Steve

The noise is different than what I had heard before.  It seemed to come from the center of the panel?!?!?  Also, tonight after sanding some new panels I pounded on it to get the fine dusk off and had thought about trying to get a mic on it... the panels Fs.  Then watch the RTA during the songs that I can reproduce the sound.  We might be able to use this same pounding and measurement to access the panel treatment.  Will a coat dampen and lower the panel Fs or will, say, 2 coats make the panel more rigid and increase the Fs?  It may not work that way but that did cross my mind tonight when pounding on the center of the panel.  Might be fun to try!?!?

I think you are spot on Steve with the large panel vs. small panel conclusion.  This is what I hear in my panels.  I like the larger 2x4 panels for more weight in the lower end but I do really miss the small panels speed, and the crisp and clear response.  Damn you Sedge.  I feel another order to PE coming on and totally intend to blame you for this next purchase!   

[sedge]

OB _newbie
Once you have removed the top layer of eps ,the under surface is more spong like and absorbs the watery pva or hopefully the watery dye,if you are artistic or have a friend who is ,you could paint a lovely masterpiece?
Is the sound coming from the centre of the panel or the centre of the exciter?if you place a 2 to 3 mm piece of bluetac in the centre of the exciter ring does this dampen the noise?

Extra coatings of any type will not do much if anything to the panel boom ,but will definitely worsen the sound of the panel ,you must remember that the more you add to the panel the more you alter the pure sound.
Steve
 

[OB_Newbie]

If you do, let us know how they compare. I'm happy with the fun with the panels since they sound so good. I have actually never heard OB speaker but really want to - How do your OB speakers compare with the panels and which one do you prefer?

Rock...the birch boards actually sounds great with rock. Just need a little bit sub boost on the bottom plus you need to get the panels on spikes or suspend them in the air.

If you don't mind me asking, what do you use to eq?
Yes - meant like a L shape.

Hey Odal,
Sorry... missed your post yesterday.

Everything said about Open Baffle is true.  I was blown away going from typical box speakers to open baffles.  Tone, detail, transparency, speed, an upper bass/low mid gives power and fullness to piano, male voices, etc. that no box speakers can match.  They have more presence and better imaging that our panels... had I been listening to a typical box speaker I would have balked much less about the panel "haze".  With OB you can hear lips moving, singers taking a breath, etc., etc... detail is amazing without any harshness.

It was because of OB that I wanted to try the DML panels.  It was hard to reconcile how much better OB was compared to a typical box speaker so that made me terribly curious as to when other non-traditional designs could bring to the listening room.  After reading this post it sounded like panels had many of the characterists that I enjoyed with OB.  Line arrays even more so as it ought to bring all the things I like about OB plus reproduction of "live" recordings that panels do so well.

Can't say which is better... I like listening to both the panels and my current open baffles.  I want to give it more time before I say which is best... if you can even say "best" (best for who!?!?  We all value different qualities).  And we have more work to do with the panels.  I'm still not completely happy with the bass quality.  OB bass can be amazingly quick, tight and can go low.  But I'm not building panels for bass reproduction and for the music I listen to they suit me well.  I won't say who it is exactly, but there is a guy on this forum who starts with "S" and ends with "teve" that has me jazzed about multiple smaller panels again.  I really want to see how a multiple, small panel DML speaker will perform in the bass region.  I was able to make decent bass at low levels with the 2x2 panels with EQ.  So twice the surface area and exciters should provide enough bass for my listening preferences with the quality I want... should also be more sensitive and dynamic.  But we shall see.       

For EQ, right now I use my Behringer DCX2496 for cross-over and EQ duties.  I'm thinking of trying a Behringer 31 band EQ. 

Gotta run...

[Odal3]

Thanks for sharing your impressions! Agree- best sounding is not a good term especially in the world of audio...can get you in trouble on forums like this  Sounds good and prefer works too.

Finally cut up the xps board, and waiting for the glue to dry up! Will be some interesting comparisons. Do you glue the exciters with the same pva glue but at full strength (not dilluted)

[OB_Newbie]

Yeah!  Can't wait to hear your impressions of birch vs. XPS.  I walk pass the birch ply every time I'm at Home Depot and slide a few out looking for flat ones but just have not been able to pull the trigger.   I have the standard VHB on the small panels and did glue them for the larger 2x4 panels... think its called Elmer's Advanced ProBond or something close to that.  Sedge uses the waterproof EVA and would have got that but Walmart was out of stock when I made one of my late night runs over the holiday break.

To dry the panels I've been using a hair drier... makes for some quick panel work.

Hey, what did you cut up your XPS panel with?   

[OB_Newbie]

OB _newbie
Once you have removed the top layer of eps ,the under surface is more spong like and absorbs the watery pva or hopefully the watery dye,if you are artistic or have a friend who is ,you could paint a lovely masterpiece?
Is the sound coming from the centre of the panel or the centre of the exciter?if you place a 2 to 3 mm piece of bluetac in the centre of the exciter ring does this dampen the noise?

Extra coatings of any type will not do much if anything to the panel boom ,but will definitely worsen the sound of the panel ,you must remember that the more you add to the panel the more you alter the pure sound.
Steve

Only wish I was artistic.  Someone at the PE Tech Talk had his wife paint a few panels that were pretty cool... panel envy...  I will try the dye solution and hope for the best.

This panel boom is eating at me.  The more I listen the more I notice it.  I finally went back to the small panels again tonight just to see if I was just fantasizing about them... afraid that I overhyped them and they may not sound as good as I built them up in my head.

Ahhh... NOPE!!!  They sound amazing and notably better than the 2x4 to my ears.  Speed, dynamics, clarity ... its all there as I remembered and actually BETTER than I imagined.  You were right about more of a point source... voices are more realistically sized in my opinion... that was apparent on the first track I listened to.  More obvious going back from big to small panels.

A shame... finished a 2ft. x 5ft. panel late last night and was going to try the new exciter but think I'm going with another small panel.  Maybe 20in. x 32in(ish).  Have to read over the thread of panel ratios.  Can't imagine the square panel is good.

Anyway... more panels... but have a LONG way before I catch you.

One more thing I wanted to ask.  Do you support your exciters with a spline or equiv??  I have mine just free mounted.  Think I read earlier this spring that you or one of the other fellows flip the panel every now and then and had not lost one do to vc sag.  Just curious.

Thanks,
Rich

[Odal3]

Yeah!  Can't wait to hear your impressions of birch vs. XPS.  I walk pass the birch ply every time I'm at Home Depot and slide a few out looking for flat ones but just have not been able to pull the trigger.   I have the standard VHB on the small panels and did glue them for the larger 2x4 panels... think its called Elmer's Advanced ProBond or something close to that.  Sedge uses the waterproof EVA and would have got that but Walmart was out of stock when I made one of my late night runs over the holiday break.

To dry the panels I've been using a hair drier... makes for some quick panel work.

Hey, what did you cut up your XPS panel with?

Ok - first impression from 2 x 4 xps panel using chepo exciters so I could do an apples to apples comparison to my first birch board: amazing hf detail and a bit disappointing LF. To put it in terms of the music suggestions  from this thread: the Yo yo ma cello sounds outstanding (but missing some depth) but the drum kicks on Cowboy Junkies sweet Jane doesn't sound quite right (flat - missing detail? ?).

Will do some measurements tonight or tomorrow.

I used a razorblade knife. Probably not the best way since I had do do some extra sanding to clean it up.

[Odal3]

Forgot to mention that the panels I have only is 1/2 in which might be the reason for the LF performance

[OB_Newbie]

Forgot to mention that the panels I have only is 1/2 in which might be the reason for the LF performance

Hey Odal,
Yeah, I wonder if 1/2 is thick enough for anything but the smallest panels.  I gave up on the 3/4 as there was a lack of definition in the lower registers.  There was resonant fuzziness to the sound.  Like the panel was flopping around and was not rigid enough to transfer the sound wave into the air.  But I really didn't give them much of a chance as I didn't even sand or treat them but didn't really think that treatment would make a 2 ft. x 6 ft. panel much more rigid but I could be wrong.  It was just so much different in sound quality that the game was over before it really began for me.

I still really like my 1 inch thick panels.  Plenty of high frequencies for my aging ears.   

A little update... Man, I just started listening to fresh 24 in. x 30 in panels with the new Dayton Audio DAEX32EP-4 Thruster...  after a rocky start, all I can say is holy $hit!!!!   

If you haven't updated your pucks yet you really have to.  It is a *substantial* upgrade... at least on my fresh panels...

[OB_Newbie]

Odal, what panel material/size are you using with your DAEX32EP-4s btw??? 

[exspec]

If you were to make an MTM type DML with a dipole tweeter between two small panels, what size panels would you recommend? I intend to place them above a pair of side by side 22" HFrame woofer enclosures (approx 20-200hz) on each channel. Essentially laid out like:

MTM
W W

XPS and EPS are available locally. Not sure what thickness or type to try first. Tectonic uses approximately a 6000hz xo to tweeter IIRC. My hope is that there is. Material that would perform well between 200-6000hz. My exciters are the buyouts from PE. I have 8 total. Your thoughts would be appreciated. Thanks in advance.

[Odal3]

Odal, what panel material/size are you using with your DAEX32EP-4s btw???

I currently have them on 2.5 x 5ft birch panels. One has thickness of 1/8, which doesn't sound too good, and the other has 1/4 thickness.

BTW: Here are some measurements of the XPS panels. Shows similar fall-off on the LF as the ones you posted - birch panels shows a much smoother LF, but the XPS has better and tighter high end. Mic at 3 ft (used the umik-1) - the lines shows the same panel but just with different smoothing applied.  Probably can't read too much into the chart because it is measured in my unfinsihed basement with concret floor, misc stuff and other reflective things.

[OB_Newbie]

Hey exspec,
Until the more seasoned DML guys stop over and comment...

If you were to make an MTM type DML with a dipole tweeter between two small panels, what size panels would you recommend? I intend to place them above a pair of side by side 22" HFrame woofer enclosures (approx 20-200Hz) on each channel. Essentially laid out like:

MTM
W W

I personally like the idea of a non-DML driver handling the upper octaves.  It might bring more presence to the DML presentation that, in my humble opinion, is needed.  I have heard good things about the Tectonic panels. 

What tweeter do you have in mind?  At what point you cross over to the tweeter should be done via listening sessions.  Do you have a electronic crossover to make prototyping a less painstaking task?

Assuming the physical layout above is DML T DML and modeling your design after the Tectonic panels. Their panels are for pro sound and are pretty wide but with 2 side by side H frames it looks like you have the room which is excellent.  Assuming this, I feel its important to get the tweeter positioned vertically at your listening height.  With 22" high H frames you have about 12" above and below the tweeter giving you 2 - 2 ft. panels on each side of the tweeter.  Width of the panels would match your H frames.

These are fairly small panels but think they have an advantage when it comes to integrating the panels and tweeter. Specifically, the smaller panels will act like a point source than a taller panel which would act like a line array up to a given distance.  Combining 2 point sources is preferable as a ps and line array decrease at different levels as you move away from the speaker.  This leads to a single distance where the panels and tweeter will be playing at the same level.  Not a good situation so 2 - 2 ft. tall panels are not a bad design decision in this case. 
 

XPS and EPS are available locally. Not sure what thickness or type to try first. Tectonic uses approximately a 6000Hz xo to tweeter IIRC. My hope is that there is. Material that would perform well between 200-6000Hz. My exciters are the buyouts from PE. I have 8 total. Your thoughts would be appreciated. Thanks in advance.

Me personally, I like the more rigid 1" panel material for better defined lower frequencies but in this situation the panel size is small and with the OB subs handling the last few octaves a thinner panel might be a better choice.  XPS and EPS are cheap so I might try both thicknesses to see what you prefer.  Its as more of an exercise of preferences as it is science.

Man, after listening to the Dayton Audio DAEX32EP-4 I would strongly consider using them.  I know you have made an investment already but I think you will be more than happy that you did after listening to the new exciters!  I need more time with them but with the little time I've spent they look like a serious improvement. 

[Odal3]

If you were to make an MTM type DML with a dipole tweeter between two small panels, what size panels would you recommend? I intend to place them above a pair of side by side 22" HFrame woofer enclosures (approx 20-200hz) on each channel. Essentially laid out like:

MTM
W W

XPS and EPS are available locally. Not sure what thickness or type to try first. Tectonic uses approximately a 6000hz xo to tweeter IIRC. My hope is that there is. Material that would perform well between 200-6000hz. My exciters are the buyouts from PE. I have 8 total. Your thoughts would be appreciated. Thanks in advance.

Note that there are different kind of XPS / EPS panels available depending on where you are located. Some are good - others not so much. The good news is that they are fairly cheap to try out, and if you don't use too strong of glue it is pretty easy to remove the exciters and try over. I would start with 2 x 4ft to see how you like it. OB_Newbie seems to like smaller panels, but others have reported that they like slightly taller (or slighly wider), but if you are going to cross them  that high you probably don't need too big of a panel. However, I would also recommend to experiment crossing your HFrame woofers much lower. The bass on the right type of panels can sound pretty amazing. I'm crossing my birch panels around 70 to 100, but I may reduce it even further. There are some that have panels that don't need a sub at all as well...

BTW: The HF on the chart I posted could probably be improved if I used a different exciter (this was also the buy-out exciters) and used a harder glue instead of vhb tape.