[OB_Newbie]

Apparently I have way to much time on my hands (Xmas break is wonderful)   

This time I wanted to report progress on my second XPS panel.  The new panel is 1 in. thick, 2 ft. x 4 ft..  I sanded both sides, rounded the corners (6 in diameter) and all edges with a quarter-round router bit followed by a hand sanding using 220 "very fine" sandpaper.  The exciters this time are the 8 ohm Dayton Audio DAEX58FP. 

Early observations.  After listening to my small panels for most of the day, I am in a good position to compare the panels.

* The distant and veil sound is back and even worse than I remember with the small panels.  I thought that the small panels were improving but had also honestly thought that I have just been adjusting to DML panel sound.   But I can very confidently report that the wood glue:water mix after it hardens is a miraculous and very clear improvement.   How much is attributed to the exciters breaking in is unclear.  Bottom line, the difference is *significant*. 

* The DAEX58FP exciters are not nearly as efficient as the Dayton Audio DAEX25FHE-4 Framed High Efficiency exciter that I have been using.  Only time will tell as to which one I will prefer but I can say that the DAEX25FHE-4 easily plays louder and handles a fair amount of power for such little $$$.   Very nice.   

* More bass then expected.  Didn't perform and RTA but it may be listenable run full-range for jazz, acoustic and any other music that does not have a lot of bass. 

* Like Rob, I had thought that my XPS panels did not have a skin.  I was wrong.  When I applied the panel treatment I noticed a missed a small spot (indent) in my sanding job and when I applied the glue:water treatment it would not stick to the panel just as Steve had originally reported.  So if you have XPS by Owens-Corning be sure to sand both sides as Steve and others suggested. 

* I am fighting the urge to hookup the small panels.  I'm still shocked at the difference as I sit here and typing this post.  I sure hope that the larger panels will sounds as good as the small ones... 

Cheers!
 

[Odal3]

Apparently I have way to much time on my hands (Xmas break is wonderful)   

The exciters and this thread should probably come with a warning for addictive behaviour. It probably should also state that while the initial exciters are deceivingly cheap, it somehow starts adding up after a couple of experiment...

* The distant and veil sound is back and even worse than I remember with the small panels.  I thought that the small panels were improving but had also honestly thought that I have just been adjusting to DML panel sound.   

Sounding worse??? still a but muffled? Do you think it is the thicker panel?

But I can very confidently report that the wood glue:water mix after it hardens is a miraculous and very clear improvement.   How much is attributed to the exciters breaking in is unclear.  Bottom line, the difference is *significant*. 

So if I'm understanding this right, the thicker but larger XPS panels still sounds a bit "muted" and that the re-skinning improves the clarity but doesn't take it all the way on the particular panel you are using.

Thank you all for sharing your progress and experiences.
 

[Odal3]

VH EPS AND "THRUSTER REVIEW"

Thrusters are mounted in number one position as per Monacor placement /recommendations.
First thing that becomes immediately noticeable is the significant increase in volume/efficiency of these new tech. exciters!!!!
Second is the fact that the VH EPS available here in Western Australia has no "skin" ..........it just has a finely textured surface that has no shine or anything that I can tell that resembles a surface that needs to be sanded and replaced by PVA glue.
Third point is that as expected- the 6X2 sheet at 20mm thick is far, far more rigid than standard EPS at the same thickness.

The sound is very interesting to say the least.
The speakers totally disappeared as each track or radio program changed. However, never once was there any question as to what was in the left channel, centre or right channel.
Depth was truly amazing, as was the obvious acoustic venue or closed in studio miking which plagues so many recordings.
"Dynamics"?.........WOW!!!!!.........absolutely the best I have ever heard from a DML!!!.......don't know if it's the thruster exciters or the more rigid panells? The PERCUSSION XX recording mentioned in one of my last posts is jaw dropping..........different!......strangely so.....very weird, yet so compellingly REAL!!!
Top end is very natural but not as fierce or prominent as the thinner EPS with standard exciters. Only burn in time will tell if this area changes or not as it could be the exciters or, once again, just the fact that a thicker panel is being used?
Detail?.............it's all there........trust me.
Mid-bass?.........lots of tonal colours and contrasts........truly outstanding, massive dynamics as already mentioned.
Low bass?........ Jury still out on this one.........panels are free standing and not mounted as yet.

Rob.

  This is an exciting review! Glad to hear you like it that much, and you got me to try that exciter as well. I will share some more details of my experiences soon using a new (yes - couldn't resist) 5 x 2.5' panel, but you sum it up really well. Mid-bass to ("upper") low-bass is EXTRAORDINARY!! I need to be careful until I get a high pass filter installed. I had a 5 gallon bucket with a movable handle standing 2-3 meters away from the panel. The handle on the bucket started the rattle when I turned up the volume....and the bucket was standing on a concrete floor in the basement!!!!!!

Top-end: Not sure yet, but I have many new components in my system that haven't really broken in yet so will need to play some more (new pre-amp, new amp) plus I haven't mounted the exciter correctly since I used a thicker (gue-feeling) VHB tape.

However, never once was there any question as to what was in the left channel, centre or right channel.

Are you using three panels in a two main + one center set-up or are you referring to the recording of the sound?

BTW: If you guys are into HT, you should try to hook up two panels as the Front left and right speakers - it's really good for suspense type of scenes or if out in an urban scene either in a city or forest!

[OB_Newbie]

Odal and Zygadr,
I think Zygadr has the high fs exciter.  What about you Odal... did you go with the the low fs (DAEX32U-4) or high fs (DAEX32EP-4) exciter?

Thanks guys!

Never mind... I found your posts from Dec. 12... A pair of DAEX32EP-4's are on there way.  And because I don't enjoy playing with these panel's I might have to order the lower Fs version as well.   

[OB_Newbie]

The exciters and this thread should probably come with a warning for addictive behaviour. It probably should also state that while the initial exciters are deceivingly cheap, it somehow starts adding up after a couple of experiment...

No doubt Odal... no idea what will happen when I have to go back to work next week...

Sounding worse??? still a but muffled? Do you think it is the thicker panel?
So if I'm understanding this right, the thicker but larger XPS panels still sounds a bit "muted" and that the re-skinning improves the clarity but doesn't take it all the way on the particular panel you are using.

Both panels I'm listening to are the 1" (measured thickness is 7/8") actually.  The smaller 1" thick, 2 ft. x 2 ft. panels sounded veiled and distant when I first posted initially on this thread.  However now after a week the small panels, compared to the new larger panels, are not muffled and are crisp and crystal clear.  The conclusion.  It seems to be Serge's PVA/water panel treatment... once its cured... the sound of the panel is SIGNIFICANTLY improved.  I'm sure the exciters being more broken in is part of the improvement as well. 

I hope that in a week the large panels will sound as nice and the smaller panels.  Same material and treatment (however I rounded the large panel corners and edges) so can only imagine (and hope and pray) that the 2 ft. x 4 ft. panels will sound like the small ones.     

Thank you all for sharing your progress and experiences.

Ditto... can't wait to hear about your new panel material.  I almost picked up some hardboard panels at HD yesterday.  Have you or anyone tried common hardboard?  Its hard but should be well dampened but afraid it might be to heavy.  But with the new exciter it starts to open up more possibilities in panel material.

[sedge]

Ob_newbie
Glad you like the improvement in sound from the coating ,I  myself only use one coat of what looks like milky coloured water,some pva is thicker than others as is wood glue so you will have to adjust the mixture accordingly,the gallon can of cheap pva I use is pretty thin to start with even more so after a 50 50 mix but this is usually enough to tame the eps self noise and still gives the panel a good hard surface ,I am more concerned about over damping the panel than under damping it as you can always add another coat at a later time after  you have listened to the fully hardened surface .
I usually use my wife's hair dryer to speed things up,drying one side and turning it over and doing the other side only takes a short time but you still have to wait a few days before you get the good high frequency response.
Steve

[sedge]

Just thought about what I have just said in my last post and realized what I said is not right ,the pva is not there to damp the unnatural sound of the eps surface because it has already been removed,the coating is just there to replace the hard surface which produces the sound we hear,if there is any extra damping this could be for good or bad,so keeping it to the minimum could be a good thing maybe?
Using other coatings ,harder or softer will obviously change the sound and will probably be down to personal taste,so have fun .
Steve

[OB_Newbie]

You didn't state anything wrong Steve and sure appreciate the response back.  But your second post is possibly more accurate as I too try, after thinking it over more, to determine what might be happening on the panels surface after the treatments.  I am shocked to hear such a large difference in sound quality between the 2x2 and 2x4 panels and the simple fact that a light treatment on the surface appears to have such a large impact on the sound quality/characteristics.

I am still mulling over how much is exciter breaking in and the panel treatment curing.  But I can say that I do hear significant self noise from the large panel even today; 36 hours after 2 treatments.  In your experience (and everyone please chime in), do you feel the exciter might be contributing also to the panel noise due to the stiff and less flexible spider?!?  Or is it largely the panel?!?  Could be both... and what percentage each contributes is hard to say... I just don't have enough experience at this point to determine.  To increase the sample size I will just have to build more panels I guess.  Darn.         

To get back to the panel treatment and observations...  my first coating with the small panels was with cheap white "school" glue diluted 1:1.  After listening for a day there was still quite a bit of self noise and the surface didn't seem very hard (curing for a few days may have told a different story however) so being almost out of the cheap white glue I used wood glue instead; adding more glue to that second treatment.  Now, after a week of curing, when I handle the small panels and lightly rub my hand across the panels surface the sound is notably *loud*... the surface is rough and the panel is crispy hard and light.  Yet at the same time I can listen at very loud levels and I don't have ANY self noise.

To me, this *seems* like a good surface to amplify an exciters output.  Might be a placebo effect but the small panels seem detailed... clean and "crisp"... especially compared to the new larger panels which as dull and muddy with excessive self noise.  The lack of bass on the small panels and overall leaner presentation likely also contributes to these impressions.

So conclude... I am very interested to see what happens to the larger panels as they cure and the exciters break in.  I did only 2 - 1:1 treatments so if they don't get as hard as the small panels I could always add another coat with more glue.  I think Jeffac mentioned that he did 1 part water and 2 parts glue but as you say, its going to be personal taste.  So we shall see if more glue in you magic wonder treatment over damps the panel or firms its up to actually amplify the smaller signals better?!? 

The answer is only a few days away! 

Thanks again Steve for the discovery of the panel treatment and for the responses... I especially find your, J Gale and Zygadr experiences and responses thought provoking given your time with the panels.  Harnessing collective learning is a very cool and powerful exercise.  I simply can NOT image all of us going about this on our own and coming away with such a fine sounding and musical panel!!!

[sedge]

Ob_newbie
My first suspect for problems would be the Dayton 58fp ,it has a large plate between the exciter and the panel,my preference would be to have the coil glued to the panel surface with no obstruction in between them so that the slightest movement of the coil travels directly through the panel surface.

If too thick a coating is applied to the panel you will start to add weight ,which could have the effect of making the panel sound sluggish ,swings and roundabouts again I'm afraid,so tread carefully.
Steve

[OB_Newbie]

yeah, oldschoolVlad mentioned that in an earlier post about the stupid plastic "boot" and was a bit disappointed after reading that.  He had mentioned that it would affect the high freq. response according to the modeling he performed and that a 25mm voice coil is optimal for better HF response.  I did a quick RTA looking for that affect but didn't see what I thought I would see and actually have a peak in the 18-20K range!?!?  Either way, I ordered the new high power thruster that Odal and Ziggy are impressed with so better exciters are on there way.

I've been down in the shop and made new panels and have only applied single coat this time to see if that might be responsible for any of the fuzzy, veiled and sluggishness.  But I'm going to recycle the Dayton Audio DAEX25FHE-4 and use that instead of a fresh DAEX58FP... an exciter shootout so to speak.   

Will be interesting.

[OB_Newbie]

The exciter shootout has come to an abrupt conclusion. 

The Dayton Audio DAEX58FP exciter was the culprit and responsible for the poor performance of the 2 ft. x 4 ft. panel.  Most notable shortcoming, sluggish and even boomy bass performance.  Avoid the DAEX58FP.  It might have a place with other applications|panel material but not an XPS panel.

As soon as I started listening to a second set of 2x4 panels with 1 Dayton Audio DAEX25FHE-4 the clean and delicious DML sound once again filled my listening room.  Sounding very similar to my small panels but with more bass as I would have originally expected.

Will see what improvements come with exciter break in and the treatment curing.  The new panel has little self noise but do hear it on occasion and quite sure that will disappear altogether with time.

Ahhhhhh... can enjoy music again!   
   

[OB_Newbie]

What happened here???

Comparing the freq. resp. of the DAEX58FP to the better sounding DAEX25FHE-4 you can see that the DAEX58FP does have more extended bass response which may be responsible for some of its boomy|sluggish performance???

DAEX58FP - 1. close miced'   2. from the listening position



DAEX25FHE-4 - 1. close miced'   2. from the listening position



note : Ignore the output levels as they did not receive the same signal level.

Look at the differences between the 2 DAEX25FHE-4 responses.  There doesn't seem to bee as much difference between the 2 measurements.  Then compare the DAEX58FP measurements... the close miced' freq. res. shows noticeably more bass output?

I wonder if the increase in bass response is panel "noise"?  That may explain boomy, fuzziness when listening to the DAEX58FP... wouldn't rule that out. 

Unfortunately I have already tore down the crappy sounding DAEX58FP's off the panels so no more troubleshooting and comparing can be done. 

Curious what would happen if I EQed the new panel response to match the DAEX58FP's???

[Odal3]

I borrowed a mic to do some measurements as welland once I figure out how to use it correctly I will post some plots soon.

Do you have a line chart with more detail and not so much smoothing  on? I'm just learning how to measure so I'm probably the last one to ask, but I noticed on my measurements that the boards are very sensitive to where they are held, suspension points, etc. Kind of like someone said before, you can do some equalization directly on the board.

I got the smoothest LF response if I suspended the panel, which I did by holding it by hand on the top middle. I almost got just as good if I put it on cedar rings with some moongel sandwich in between  (what drummers use to dampen resonances). This removed huge swings in the plot between 20 to 80hz and also extended the top end. Do you see this as well?

Interesting that you have a peak at the 16kplus frequency, as well as the long falloff on the 25. Perhaps that will make it easier to integrate naturally with a sub??

[sedge]

ON_newbie
The roll off does look a bit odd ,I would expect a thinner 5mm panel to look like that,are you sure you haven't left an xo setting on ,or a capacitor left in place on the exciter? It's been done before
In my gallery there is a pic of a bog standard 2x4 panel 25mm thick I would expect a response like this ,also there is a smaller 5mm panel with a similar response to yours,I would expect more from your panel.?
Steve

[OB_Newbie]

I borrowed a mic to do some measurements as welland once I figure out how to use it correctly I will post some plots soon.

Do you have a line chart with more detail and not so much smoothing  on? I'm just learning how to measure so I'm probably the last one to ask, but I noticed on my measurements that the boards are very sensitive to where they are held, suspension points, etc. Kind of like someone said before, you can do some equalization directly on the board.

I got the smoothest LF response if I suspended the panel, which I did by holding it by hand on the top middle. I almost got just as good if I put it on cedar rings with some moongel sandwich in between  (what drummers use to dampen resonances). This removed huge swings in the plot between 20 to 80hz and also extended the top end. Do you see this as well?

Interesting that you have a peak at the 16kplus frequency, as well as the long falloff on the 25. Perhaps that will make it easier to integrate naturally with a sub??

The RTA measurements above are not accurate in the low freq. range. I posted them to show the differences between the 2 exciters on the same panel.  Overall, the low frequency output is quite good with the DAEX25FHE-4 and probably plays flat to 65-80Hz in my estimation.

These measurements are taken with my iPhone 5 with the Dayton Audio iMM-6 Calibrated Measurement Microphone.  I experience the same problems when measuring low frequencies with my open baffle bass bins so assumed that it was due to the bipolar response of the OB and these panels.

I'll play more tonight and research a little as to why I get this.   Any ideas?!?

[OB_Newbie]

ON_newbie
The roll off does look a bit odd ,I would expect a thinner 5mm panel to look like that,are you sure you haven't left an xo setting on ,or a capacitor left in place on the exciter? It's been done before
In my gallery there is a pic of a bog standard 2x4 panel 25mm thick I would expect a response like this ,also there is a smaller 5mm panel with a similar response to yours,I would expect more from your panel.?
Steve

Its an issue with the mic/phone and RTA.  The response from the panels (thankfully) don't sound like the measured response.  They have pretty decent bass and almost enough to not really need a sub...  probably plays flat to 65-80Hz in my estimation. For the music I listen to it gets me about 95% there. 

We shall see... I really like the idea of full-range panel that weights a few pounds and can easily be carried out of the living room when needed.  Its a really nice benefit for me and these light panels!!   

[sedge]

OB_newbie
If you are sitting within 10 ft say,of the panels you should be getting a pretty good all round performance on acoustic music,unnatural close Mic recordings with excessive LF can cause problems though.
As you probably know They can start to sound a bit mushy if to close to the front wall .
Steve

[OB_Newbie]

Hey Steve,
My panels are a bit over 3 feet from the back wall and just under 4 feet from the nearest side wall so are able to develop good bass.  I listen at a distance a little over 10 feet to the seated position.  So not to close to room boundaries or anything like that.

I had a busy night last night but before the night was done I hauled out my last boxed speaker to validate measurements and I got very similar results.  It is a small full-range monitor using the Tang Band W4-1320SJ in a 7+ Liter slot loaded enclosure with no BSC... wired straight from amp to speaker.  The modeled response I believe was an F3 of 72Hz.  As you see below it shows the same roll-off and I know that the speaker is quiet flat to 85Hz or so...   



1 Dayton DAEX25FHE-4 exciter on a 2 ft. x 4 ft. 1 inch thick XPS panel, close miced'


After a quick listening session, the panels are more sensitive and did have more bass output confirming the notion that the panels are playing much better than the measurements suggest. 

Thanks,
Rich 

[OB_Newbie]

Odal and Ziggy,
Any updates on listening impressions of the new exciters?  I should be receiving mine soon and curious if either of you (esp. Odal) have tried any other panel materials now that we have a more powerful exciter... more options??     

Thanks fellas...

[Odal3]

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.

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.

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


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