[zygadr]

emailtooaj, .........good work. What sort of epoxy are you using?............this is important for us to know as there are many types and we are all over the planet.

panomaniac.......so was I  ......................are you interested in UFO's?..............send me a private email

Yes, it's called officially E.P.S......EXPANDED POLYSTYRENE FOAM.......VH grade (very hard).

Here is a couple of links that may help? In the U.S. it may actually be called ''STYROFOAM''...........I'm not sure. It's also called ''bead board'' and is probably available in a harder grade?

http://www.univfoam.com/styrofoam-vs-polystyrene

http;//www.en.wikipedia.org/wiki/Extruded_polystyrene     

It's noticeably more harder and durable than regular poly...........smaller, denser bead compression but still VERY light. Styrofoam may be more like solid plastic sheet and way too heavy......hard to say.

Check the above links and inspect both types.

The time has finally come to remove the exciters off my prototype panels (which were kindly supplied as largish off cuts, but of different dimensions ) and order in two large, professionally cut 10mm panels.

I will wait for emailtooaj's response before I do, as he is on to something that could be of great significance

[zygadr]

Sorry, here's the second link:

http://www.en.wikipedia.org/wiki/Extruded_polystyrene

Extruded and expanded poly are two different things if I'm not mistaken after reading the links?

[panomaniac]

OK, cool.  It's Styrofoam.   So I need to look for the stiff grades.  I'll go look at the sheets they sell for insulation. I can't remember if it's soft or hard foam.

The flying saucer is from;
http://en.wikipedia.org/wiki/Everything_You_Know_Is_Wrong

[j gale]

I  got 2 pieces of the extruded polystyrene. Here in Canada there is an Owens Corning brand that is pink colored. Thinnest I could find is 13mm or 1/2". It's 2'x8'. It seems to be very promising, light and rigid. Probably the same as the blue Dow stuff. Much lighter and louder than cardboard and also cheap to buy. So far pleased that it has good highs (maybe a little bright)and to my ears has a natural sound. I 'm just starting to play.

[zygadr]

Yes, it's just a harder grade of your run of the mill polystyrene foam..............simple as that, but as I said.........inspect the stuff carefully, give it the crush test and scratch test first.

Some of you may remember the Betagni type wooden frame polystyrene membrane speakers with the opening at the back in the shape of a violin?............these were driven by dynamic speakers attached to the poly - tweeter and woofer drivers.
These panels were available in various covered versions of your typical 70's odd color patterns including ''zebra stripes''

The covers were printed cotton fabric and glued via spray on glue to the poly.
Maybe that was a method of dampening also?
I removed the cloth from my pair that I once owned a few years back and the sound DID change.............can't remember if for the better or worse?..............something to ponder on.

j gale...............welcome back!..................I think we have hit the mother lode with this material.

Here we go!.......................

[emailtooaj]

Alright. My second coat of epoxy may have been a little to much.
I filmed the panel with my phone and posted it here...
http://www.youtube.com/watch?v=vwmg49UlHpc

The sound was still decent, but with a 1" panel and 2 coats of epoxy, it might be a bit too much. I have some more material and will try it with just 1 coat and 2 exciters ran in series and post the outcome.
The 3 exciters in series just didn't cut the cheese...well actualy they did

Zy, here is a link to the epoxy I'm using...
http://www.westsystem.com/ss/g-flex-epoxy

I don't remeber who posted about Owen Cornings pink board...but yes! that is correct path! Its called PINKCORE and I have been meaning to pick some up and try it out. It only comes in .75 inch were I live and I think you said you were in Canada where you're able to get .5 inch. I think I even read somewhere that you go as thin as .375 inch (3/8th).
I have been using DOW boards which are blue in color(BLUCORE). The guy I have been getting the panels from said that PINKCORE from Owen Cornng is identical in composition. It's just pink to signify residential use. Where as DOW blue poly is for commercial/industrial use and have a stricter quality control? So he says!

I'm sure that DOW/Owens is very similar (if not identical?) to EPS VH grade zygader has been using? Why those silly Aussie's call it VH grade?

Here is the link to the DOW blue boards if anyone is interested....
http://building.dow.com/na/en/products/insulation/rigidfoam.htm
And the link to Owens PINKCORE...
http://commercial.owenscorning.com/foam/products/pinkcore.aspx

I'm hoping to get .5 inch PINKCORE somewhere in the US. Anyone know where I may be able to get it? Please post a link or vendor phone number if so!!

So my next course of action is to put on 1 very thin coat of poly and mount the exciters at that point. This should break the camels back!!

Zygadr... did you make those horn speakers in your posted pics? If you did, you mind PM'ing me?

One more thing...If you saw my linked video, you will notice I have my panels hanging in free air. Can anyone tell me what difference they experienced when bracing the exciters and mounting in a frame as opposed to hanging?

Peace Out!!

[zygadr]

emailtooaj, luv thje video .......and thanks for the links.

Over here we have the blue stuff, pink stuff, and yellow. All of these are not at all anything like what I am using though .........guess that's the difference in products around the world. Extruded polystyrene over here is not like EPS............it's more like solid plastic sheet.........very heavy and sold under the title of ''ISOBOARD'' and the thinnest is 30mm(1.25inch).

Anyhow,the two part epoxy you use is available over here under a different brand, but is still a two part set used to lacquer furniture and table tops. It's very thick and equals something like 15 coats or more of varnish

You MUST get thinner board from somewhere............this one inch stuff you are trying is likely way too thick for high frequency efficiency..............who knows?

In regards to your hanging sheets, do you get any buzzing or unwanted odd resonances?
When you mount the poly to a frame, usually any resonances are negated. Sometimes a spot here or there needs a blob of silicone between the panel and frame. It's sort of like tuning the panel I suppose.

Yes I did build the horn speakers(sort of). I'll send you a P.M.

[zygadr]

More listening last night has reinforced the publicised figures that sensitivity and S.P.L. is GREATLY influenced by the panel material.

The poly is far louder than anything else tried..................FAR LOUDER

What is now happening is that the exciters are more effective in converting their output in to the panel rather than being choked BECAUSE of the panel.

As poly is so light, it takes next to nothing to get it in to B.M.R. mode, hence the increase in loudness and high frequencies.

I think we are on the right path here but need to be cautious that any coatings or mounting methods are not ''destructive'' rather than ''constructive'' 

[emailtooaj]

I agree Zygadr 135%!!
I lived and learned with the 2 coat of epoxy
But after listening to the panels more and letting the epoxy cure more (2-7 Days) the highs have increased. How much I couldn't say...but...an educated guess would be approx +1-2db in the 12-15k range. I haven't tried a freq sweep test yet. I need to find a good, quality, FREE tone generator for my computer.
I was trying to research your panels Zygadr, are you saying the XPS (ISOBOARD) panels resemble more of a plastic consistancy than foam?
Can you link(if you can find one) a close up, detailed picture of the material itself?
It seems parts of the world have thier own termology for the same stuff?

[zygadr]

emailtooaj..................here's the Australian link to where I have just ordered two large cut sheets for myself today:

http://www.foamsales.com.au/products/polystyrene/
Isoboard and other stuff is all there.

This site will give you an indcation of how confusing this foam stuff can be unless you go there in person and do the ''touchy touchy trick''

With the epoxy, I have a concern.
Does it add a lot of weight to the foam?
If you perform the ''scratch test'' at the back and listen to the scratches from the front, is there a dullness compared to raw uncoated foam?
If there is.............it could mean trouble I'm afraid

Going back on this project, I discovered the FOREX SMART sign making material that had far superior highs due to the scratch test.
However, ''raw'' polystyrene in a hard grade was even louder and better in the high frequency transmission beacause it's surfaces were NOT coated with solid but thin polystyrene facers like the Forex

So,............we need to realise that these exciters have a weird way of transferring audio frequency energy through various materials.Many mistakes have been made with how to attach the exciters to the panel also

To me, I have come to the conclusion that any solid material(closed cell, vinyl, plastic)between the foam surfaces act as sound blockers for some reason.

This so called ''scratch test'' is the most important indicator(thanks sedge) of how well the sound will be transmitted through a material..........it hasn't failed me yet

[zygadr]

Have just gone in my lunch hour and paid for my order of two VH grade E.PS sheets including delivery(cheap)
When I faxed the details to them this morning, they were a bit shell shocked as it contained a number of ''requirements'' ............no dents, dings, scratches, splits, chips, bowing /warping and specific instructions on packaging with the inclusion of the off-cuts. No mucking around here lads!!

Sheet size : 72 inches X  29 inces X  0.4 inch.........it's a big'un ........especially when a frame has to be built around it

This will either be : the beginning of an amazing panel speaker, OR............I'm starting my own surf board business

Let's re-visit the advantage of the NXT TECHNOLOGY:

1. NO CROSSOVERS.....................NADA!!!!!

2. NO CROSS BREEDING OF CONE MATERIALS/TYPES

3. PERFECT COHESION..............ONE LARGE SINGLE RADIATING SURFACE

4. NO ''LINE ARRAY'' PROBLEMS

5. FANTASTIC OMNIDIRECTIONAL, ENVELOPING SOUND FIELD

6.EASY TO BUILD, COST EFFECTIVE............NO STEP UP TRANSFORMERS, HIGH VOLTAGE POWER SUPPLIES, WIRES, RIBBONS OR MAGNETS

7.AMAZING TRANSIENT SPEED, EASILY ENABLING INDIVIDUAL STRIKES IN DRUM ROLLS ETC..........SCARY!

8.NOW....HOPEFULLY,............soon........... GOOD HIGHS, GOOD SENSITIVITY AND EVEN BETTER SOUND OVERALL.

[DanTheMan]

Ziggy, do you plan on rounding over the edges?  Or am I getting ahead of myself here?

Dan

[zygadr]

Hi Dan,......rounding edges?........... not yet................but it's under consideration as it may have a greater effect than I am prepared to believe in at the moment.

[DanTheMan]

Oh, how longs the wait?  IOW, when are they supposed to arrive?

Thanks,

Dan

[grantnsw]

Zyg,

re   NXT's  8  advantages..   WOW   
I am enthralled.  Your determination will soon pay-off big time, I'm sure.
congratulations.

[zygadr]

Dan, should have them in the next day or so..............hard to say as I have never dealt with this company in the past except for free off cuts.

grantnsw..............thanks mate!..........I ve nearly had a nervous breakdown over this project and had to pull back for my own sanity and reclaim a clear head ......here's a few more advantages I remembered after the event :

NO SINGLE DRIVER, TWIN CONE(OR NON-TWIN CONE) ''SHOUT''

NO SINGLE DRIVER BANDWIDTH LIMITATIONS

NO HIGH FREQUENCY ''BEAMING''

NO NEED FOR CORRECTIVE NOTCH FILTERS ETC!

NO STUPID ''SWEET SPOT'' AND THE NEED TO CLAMP YOUR HEAD IN A VICE TO HEAR THE HIGHS AND ''SOUNDSTAGE/IMAGING'' !

NO CRITICAL EXPERIMENTATION NEEDED FOR EXACT AND PRECISE ROOM PLACEMENT

NO NEED TO ADD SUBS OR WOOFERS TO OPEN BAFFLES TO MAKE UP FOR THE LOSS IN BASS

NO BOXES AND THEIR DAMNED COLORATIONS!

[emailtooaj]

NO SINGLE DRIVER, TWIN CONE(OR NON-TWIN CONE) ''SHOUT''

NO SINGLE DRIVER BANDWIDTH LIMITATIONS

NO HIGH FREQUENCY ''BEAMING''

NO NEED FOR CORRECTIVE NOTCH FILTERS ETC!

NO STUPID ''SWEET SPOT'' AND THE NEED TO CLAMP YOUR HEAD IN A VICE TO HEAR THE HIGHS AND ''SOUNDSTAGE/IMAGING'' !

NO CRITICAL EXPERIMENTATION NEEDED FOR EXACT AND PRECISE ROOM PLACEMENT

NO NEED TO ADD SUBS OR WOOFERS TO OPEN BAFFLES TO MAKE UP FOR THE LOSS IN BASS

NO BOXES AND THEIR DAMNED COLORATIONS!

Amen to that!!

[emailtooaj]

Zygadr... after your comment on the thick 1" panel I've been experimenting with...I do agree and disagree , 1" may seem to much. But it was enough encouragement to digg a little deeper on the research end. In doing so I think I came across something that might be of significant value and CHEAP in cost!! I did a search for the material on this thread and a few others and I don't think anyone has tried it yet? So I ordered it and will release this info after it arrives(don't want anyone to get in a hissy for no reason as of yet!).
But back to my panels with epoxy backing (well one of 'em any ways ). I did the scratch test on the epoxied one and the sound is deadend when you scratch the back. The un-epoxied one is brighter sounding.
Here is were I think things get more interesting between the two panels ...
When you tap the panels with the cushion of your finger...the plain panel has a very dead thud to it... the epoxy panel has a reverberation to it after you tap it . The best way to describe it, is it sound like tapping on a Bass Drum Head with you finger.
I'm a drummer so I'm very familiar with this sound.
You may be asking why I find this interesting? If not... I'm telling you guys anyways !!
If you remember my earlier post I mentioned that the epoxy panels seem to have a even more uniform sound thoughout the panel. And also the highs are a lil more crisp.
Excuse me if I can't explain this in writing
Zygadr... I also took into consideration your comment on Exciter attachment and how different glues, adhesives, tapes, etc. effect the sound output in some fashion. I believe I have found a way to over come this, by assembling the panel/exciter in a slightly different fashion. I will explain what I'm talking about after I do it and try it out. And yes it still involves epoxy...
I still believe that poly and epoxy are the ticket...I think we have the poly down...no I just need to get the epox down...I feel I'm 70% there now!! Just minor tweaking

Keep it Rocking!!!

If none of this makes sense...i'll explain more when sober

[zygadr]

Sounds good emailtooaj!

Give us a quick word on the panel material you have found.......no one will get in to a ''hissy fit''..............we are all adults here..........well most of us

It's good to hear that the epoxy has a reverberation or ring to it because Podium Sound designer Shelley Katz once said that the beauty of the Nomex honeycomb material was that it ''rings like a bell'', which is desired......apparently

However!....................lets be VERY CAREFUL here and not create a monster that has a panel that has ''self noise or resonance'' that is destructive to the sound

Remember the 10mm FOREX smart?............it too rang when hit, but also , on certain frequencies, had a self noise that sounded like a wooden plank with music attached  ............very annoying and that's why I never bought any of this expensive stuff!

Attach an exciter to a piece of 10mm thick Balsa Wood and you will see what I mean

The way I see it is that there is a balancing act between panel resonance and panel dampening.
Resonance is good and so is dampening................but too much either way and severe compromises and problems are on their way.

Even good ol' ''GATORFOAM'' from the past had vitually no self noise, but was way overdamped and heavy to obtain any efficiencY in S.P.L.

So tell us about the new material!..............AND STOP DRINKING!!!!

[el`Ol]

There is spring steel mesh with 550 g/m^2.
http://www.bueckmann.com/Feder.pdf
Could be sealed with glue spray and the linearity is excellent for sure. Maybe I'll try.