[j gale]

Hi Odal3,  In my opinion and according to my experience the bigger the better. I'm using 3/4" and like it. ( a harder version than the cheapest but not by much) So far I have found the Monacor to be the best position. Presently using 2'x4' with one exciter (no need for more because EPS is so light) and a 15 inch woofer in an H frame (open baffle) to help with bass. I would be tempted to try 2 exciters with panels 6'x 2.5' or bigger. If your panels are big enough they can handle the bass too. My thought is that Monacor position 1 from each end might be good for a large 2 exciter panel, but just one exciter may well have superior sound. I can't stress enough to get rid of the skin that is produced by (presumably) heat in the cutting process and replacing it with a natural sounding one.

[zygadr]

Hi Guys, will be getting 20mm VH EPS this week and will sand down the faces and coat with the PVA glue suggestion.

With regards to using a single, versus multiple exciters, I must stress that using more than one exciter causes something sinister to happen  . I can't actually put my finger on what this phenomenon is, but it IS audible and some of the'' DML magic'' is lost compared to using only one single exciter. This happens on braced exciters as well as free mounted exciters as I have recently discovered. The ''DML magic'' is still there with multiple exciters, but at a reduced effect............very strange. I would guess that even with the correct formulas and Monacor placement, there is a detrimental interference of the bending modes across the panel with multiple actuators at work (possibly ''against'', rather than ''with'' each other?).

The new exciters I have will be unbraced, and although they are heavier than the rest of the types we have used, they have a larger round foot area with VHB tape that is more than adequate to hold it to the panel. I may even decide on using glue at some stage, but this is not a definite as yet.

[Odal3]

My wife asked me to run to the home improvement store to pick up some xmas lights today. With the additions of the lights (which I almost forgot) I came home with two 4 x 8 ft panels. She only smiled and shook her head. Grateful for her being so understanding. Anyways, one of the panels is eps and the other is xps. The one that sounds the worst will be used for actual insulation. Only had a chance to hold up one cheapo exciter to the panels for some initial listening tests. At raw form the harder xps sounded better, but once I pealed off the foil on the back and plastic skin from the front of the eps they sounded about equal but it's hard to tell when only holding the exciter.Yes they sound is a lot louder than my birch board panels. But, one low power exciter is not strong by itself to vibrate the panels as much as the 4 monacor placed exciters on the smaller but heavier birch board does. I could only get the highs freq. when placing the exciter close to the edge of the monster sized panels. Will do some sanding and treatment next week and let you know how I like them and if I can get them sounding better than the smaller birch panels. Will also get some of the newer exciters plus cut the panels down in size. Maybe 4x4 or 6x4. Will also need to find some better supporting spine since the large eps panel easily bends over. The place I went to had the 1/2 in which maybe was a mistake since the 3/4 looked like they were rigid enough to lean against a stand or wall unsupported.

[zygadr]

So, .........it seems that we have dumped the "MOTHER OF TONE" theory in preference for "THE PLASTIC FANTASTIC" alternative...........that's only if you  treat the "rough as guts" VH surface to approximate the "smooth as a baby's bum" equivalent and coat the faces with more plastic?!

Let's get a sense of what is happening here shall we?

1. We have EPS (at least some of us that have been paying attention) which is PLASTIC
2. We then sand it down smooth "to get rid of the plastic sound"
3. We then coat the surface/surfaces with PVA glue (PLASTIC).......to further reduce the PLASTIC sound and/or self noise??
4. The Podium Loudspeakers that we have based our D.I.Y. speakers have a sound producing panel that is nearly 100% ..........PLASTIC
5. Electrostatic loudspeakers /headphones that are considered to be one of the finest loudspeakers /headphones on Earth havie a moving diaphragm made of ...........PLASTIC
6. Magnepan Loudspeakers have a moving diaphragm that is made of ...........PLASTIC.
7. The speakers of days gone by had sensational top end performance due to their use of Mylar (PLASTIC) dome tweeters.

Admittedly, we have different forms/compositions of plastic compared to what others use, but the end result is still a plastic diaphragm.
I will not be sanding or coating my EPS panels due to a sudden and unexpected occurence during numerous tests here at home.
If you really consider that this practice improves your sound then by all means......go for it.

[jeffac]

Zygadr
Sorry ,you miss understood what I was saying ,I was not talking about roughness but hardness,the vh eps that I have was cut with a hot blade I think , which melts the surface and forms a hard plastic skin .
I think jeffac says his panels were cut in a different way ? As he says his panels have a soft surface , obviously this makes a big difference to the sound,so maybe we need to know how it will be cut before buying and save a lot of work softening the surface(removing the hard plastic skin).
Hope I have made myself clearer.
Steve.

Hi, All I can say is listen to Sedge! whichever poly styrene panel you are using EPS or extruded sand the surface off on both sides and the edges too. You will be left with a surface that has a velvety feel, but more important the plastic sound will be gone. jgale

Been working on other projects and travelling but thanks jgale, 'velvety feel' is what I meant by 'soft feel to the touch' that Steve misunderstood for the sanded round over edges of my VH-EPS panels, not the panel surface. The panel surfaces are slightly rough (indented) and I guess cut with a hot-tensioned wire, and that this will be common practice for any panel pieces cut from the large blocks (which for those I saw are maybe 5 m tall, 2 m wide and 0.5 m thick from memory, so anyone wanting large panels, that'll be about the size you can get them ). Very keen to get my sander out when I get home thanks to you usual suspects. Any tweaks that improve the sound of my panels will have me smiling even wider.
cheers.. jeffac

[j gale]

Zygadr,   Looking forward to hearing what you have discovered. Re: plastic, I agree that we have had some good sounding plastic. I especially liked some mylar tweeters. I would not have thought that sanding the natural skin off EPS and treating the surface would make much difference, but it does. PVA sounds better. It is still a plastic but better. I also like the effect of a coat of shellac. (still trying to determine how much etc.) I'm am pleased that I can alter the sound of EPS to the point that I am happy to listen to it and I suspect that it can be improved even more.

[zygadr]

Hi j gale.
Don't get me wrong, if people feel that sanding and coating the EPS improves the sound, then I will not argue with that. After all, we all have different ears and perceptions of what sounds real and what doesn't.

I am very surprised at the initial tests of the new thruster exciters............they may be the smoking gun that could change the course of all our D.I.Y. efforts in the past........one can only hope?
Wish I had more time to permanently mount them to the new panels . Please be patient all..........a storm is brewing...

[Odal3]

I haven't done the sanding yet of the EPS boards I just got, but I cut them in half to make them more manageable so they are now 4 x 4'. The 4 x 3' birch boards with four exciters still goes lower judged by my ear than the larger EPS board, which has more higher frequencies.

Zygadr - These are the ones you got, right? DAEX32U-4?

[zygadr]

NO.........Odal3........I have the METAL spider version!!!!! .......DAEX32EP-4.
There are two models of exciters that have this metal spider version which I believe have been developed to stop the dreaded voice coil droop as well ensuring that the exciter, after mounting, stays exactly vertical to the panel rear - without ever falling off or creating distortion due to magnet/voice coil misalignment........forever!

There is no need for any bracing of the exciter.............which can affect the sound quality of the end result due to spurious vibrations transferred in to the panel's supporting wooden framework.

However, the version that you have should be fine as far as I can see as it does not have the typical loudspeaker driver accordion style, weak cloth spider ( that is if you do not wish to brace your exciter).
Be mindful though that a plastic spider, may in the long term, deform from the weight of the much heavier magnet assembly(compared to the majority of exciters so far).........this is only a theory and may never happen.

It is important to remember that any type, and ESPECIALLY the steel and heavy plastic spiders on these exciters will still take some time (maybe a lot longer!) to break in ! ..........I cannot stress this fact as it is not just a figment of my imagination.........it is a FACT.......... trust me!

[Odal3]

EP version ordered and on the way! This will be fun.

Btw: I have always thought that the panels works the best for recordings of  live performances with acoustic  instruments -piano, guitar, violin, and even drums (if supported by a sub).  as well strong vocals. In other words, clean and warm sound with articulate definition of the instruments.

Yesterday I found some old CDs from 1993 with live alternative rock recordings. I hooked up dual subs to get the depth, and wow - the panels ROCK the distorted guitars just as good!

[zygadr]

Odal3, it's not my job to judge your taste in music, but until you hear a full Symphony orchestra in flight, you will never experience what these speakers really excell at in a way that is truly jaw dropping in realism.
You will be transported straight in to the concert hall as if you are THERE !!!!!!
This phenomenon is not evident in many other standard cone driver as well as panel loudspeaker systems.........I have have owned Electrostats, Maggies and many high end box type speakers.
Owners of these other systems can protest as much as they want...............I know the truth...........and I have found the secret to audio nirvana after 40 years.

[Odal3]

Audionirvana ...If so, it's time for some pictures of the set-up! Btw -What amp are you using? I have been using a Tpa3116 amp which matches well with the panels at least in my room.

Music taste is funny and it comes in phases for me, and right now I'm really into simple acoustic guitar and piano of most genres with one or two exceptions. But yes, the panels do a great job with symphonies and other live concert hall performances. Really enjoyed listening to the 2010 nobel price concert yesterday.

I must have the wrong type of eps boards or I did something wrong ( not too unlikely) and created a mess when I lightly sanded them down the surfacea with a fine grit. Kind of created a snowstorm of white "fluffy" things. The boards break up in a similar way as the white packing material used for tvs and computers. Doesn't matter how lightly I touch it with the sandpaper - small pieces breaks loose here and there. I dont think I will try adding the white  glue skin since the EPS boards I found are too fragile + edges looks bad. I did not get the velvety surface. Will try to see it works better with the XPS boards which looks to be harder

JD

[xit]

Hi guys

just a quick talk about my project (something is cooking at the moment ...)

Recently i managed to have white gator board 5mm and 10 mm, black gator board 5mm, and kraft paper skin gator board 5mm
They all sound different but frequ resp follows a bit the same pattern ... the foam seems to be similar (not sure)
but the skin are very different also, the white one is has a plastified paper like skin and it sounds not bad
I think the skin helps the bending strength so i decided to test the use this type of panels

Also i managed to have 6 mm honeycomb cardboard too, which i shellaced and also it sounds ok
My quick test seems to tell that cardboard sounds more natural and got more highs,
and the gatorboard sounds more precise and sharp but lacks of "meat"

I measured all the panels but with only the exiter held on the panel with the hand, this is not really reallistic as
the panel/exiters will be not held like that at the end and will be also glued but, if you're interested i can post the measurements
Soon i'll do it better by sticking the exiters on the panels but it'll destroy the panels if i remove the exiter from it
so i have to wait to have more panels/exiters to make new measurements.

Also for exiter i decided to use one not very common for my test (unknown on parts express ??)

DAEX32UT, findable for ex here  http://www.amazon.ca/Dayton-Audio-DAEX32UT-4-Ultra-Tripod/dp/B00M2925A0
                                           
datasheet: https://solen.ca/documents/pdf/dayton/daex32ut4.pdf 
                                             
It has a very strong BL (16,4 !!  ) and it is very different from other exiters
when it's vibrating the exiter foot doesn't move (it's in hard plastic) but all the exiter and panel moves
(see the foot view and profile view) and you've got the tripod mounting which are really
useful for rear mounting the exiter

So with this exiter, the panel can be free floating and everything is held from these 3 points
(i noticed the contact of the panel with something will modify frequency response SPL and also bandwith)

Also i noticed in my measurements that DML panels suffers from not very flat frequency response
and a lack of extremity in spectrum so i decided to correct it via DSP and managed to make my panel
sing alot higher than the 10kHz, just as a normal tweeter, but not in the lows because the dimentions
are not big enouth, but i noticed with a bigger panel i could have the good 50Hz well ...

Actually i use a white gatorboard 10mm panel because it got more highs than the thinner one
but i'm not happy with it at high levels, distortion is present.
At low levels the sound is good but with high levels it just f**cks my ears up
I think it's the panel or the exiters ... that's a big problem, (crappy taiwanese exiters ?)

I will have soon more exiters and new panels with new materials, mainly hi tech ones
but it's not easy to find, patience...

cheers

xit

[oldschoolVlad]

Xit,
It seems like there is a mistake in the Tripod docs regarding BL=16.4. It’s just impossible to get 4 times stronger driving force than the Thruster’s one considering the fact that both of them have the same motor and electrical resistance. It might be real if  the Tripod’s voice coil mass will be around 17 grams (extremely thick wire), but it is not. So, despite Xmas is not so far, we all know if miracles do happen or don’t ........

p.s. Waiting for your measurement pics, I'm going that way too.

[xit]

Hi

Thanks for the explanation oldschoolvlad, i thought like you it was a mistake but i was not sure at 100%
Here's the answer of Dayton when is asked why this model is not present everywhere

Hello Xit,

Thanks for your inquiry.

Unfortunately, we are no longer carrying the DAEX32UT-4 exciters. We do apologize for the inconvenience.

Best regards,

 

Jill Chupka

Marketing Coordinator

Dayton Audio


 

[Odal3]

Wow. First quick test with the EP exciter and this is something completely else as already pointed out. Massive force and sound. Keep in mind that my other exciters are the cheap ones with legs (which now have been removed), but so far I'm really impressed. This new exciter played louder than 4 of my old ones! Will mount it properly later this week and report back. JD

[Odal3]

Btw, I asked parts express about the diff between 32U and 32EP but didn't get too much info:
"It is a new product and Dayton has not published the spec sheet in our website format yet. It should be up in a week or so. The FS for the DAEX32U-4 is much lower 160 Hz compared to the FS pf 395 Hz with the DAEX32EP-4. That is the main difference between the two that I can see.  "

[zygadr]

Wow. First quick test with the EP exciter and this is something completely else as already pointed out. Massive force and sound. Keep in mind that my other exciters are the cheap ones with legs (which now have been removed), but so far I'm really impressed. This new exciter played louder than 4 of my old ones! Will mount it properly later this week and report back. JD

Told you so!!

Btw, I asked parts express about the diff between 32U and 32EP but didn't get too much info:
"It is a new product and Dayton has not published the spec sheet in our website format yet. It should be up in a week or so. The FS for the DAEX32U-4 is much lower 160 Hz compared to the FS pf 395 Hz with the DAEX32EP-4. That is the main difference between the two that I can see.  "

Have a look at the Podium style exciter also available from Parts Express ( ''high shove'' version)..............it also has a high FS. I feel that in the case of exciters, that the FS is not that important due to the various panel material sizes, types and weight differences that all have a great effect on the bottom frequencies. I could be wrong, but this is my theory at present.

[sedge]

Oral3
I had a look at my first sanded panel and it too looks a mess , lots of deep marks caused by build up of debris under the sandpaper ,also the edge of the sandpaper or even a crease can rip through the unprotected inner surface.
This could also happen to the foam type poly, so be very gentle and only sand small areas at a time and keep the paper very clean with no sharp edges ,personally I would not attempt to round the edges at this stage but just leave the last few inches uncoated ,this will hopefully have the effect of damping the reflections.
The old panel did have rounded edges and that too was a mess ,I never tried that again.
The panel had had many exciters glued to it and remove but still sounded good for a test panel,the thinned pva coating bonds and seals any loose surface,
Steve

[sedge]

Also do not worry about trying to get a surface as smooth as a baby's bottom ,the surface once treated should feel a little like the sandpaper's surface,also if gluing the exciter on , give the glue a few days before testing as the HF will improve as the glue hardens . I think you should only scuff off the eps surface not sands deep into the panel,hope this helps
Steve