[zygadr]

I think of cars.

MB with big capacity V8 on Autobahn vs Elise (or Caterham) on country road. 

High power vs agility....

Eventually, nothing can deliver perfection in every aspect. This brings us back to multi-way speakers.

That's why I never got rid of my massive three way horn system! 

[CLS]

I did. 

I don't have the space for all of them.

[inrank]

If anyones interested, got a reply on the Dufaylite Ultraboard-

Ultra Board 2000 x 600 x 6mm Type : R = £6.33
Ultra Board 2000 x 600 x 10mm Type : R = £7.64
Ultra Board 2000 x 600 x 18mm Type : R = £9.28

2400 x 1200 x 6mm Type : R = 3.11kg  (2000x600 = 1.55kg)
2400 x 1200 x 10mm Type : R = 3.41kg (2000x600 = 1.70kg)
2400 x 1200 x 18mm Type : R = 4.09kg  (2000x600 = 2.04kg)

Is that particularly good or bad, for 1x Visaton EX60S Exciter per board?

[CLS]

If I were you, I'd start with the smallest and thinest one.

Good luck and have fun 

[el`Ol]

That's why I never got rid of my massive three way horn system! 

How does it sound when both are running parallel?

[el`Ol]

Wood would be better because......?

More bass?

Much more linear. I once measured it statically, not just a listening impression. Didn't make harmonic distortion measurements, however. 

[CLS]

It's interesting. Would you please share more about that measurement? 

[zygadr]

How does it sound when both are running parallel?

The horns were way better and overpowered them in each case.

[zygadr]

If anyones interested, got a reply on the Dufaylite Ultraboard-

Ultra Board 2000 x 600 x 6mm Type : R = £6.33
Ultra Board 2000 x 600 x 10mm Type : R = £7.64
Ultra Board 2000 x 600 x 18mm Type : R = £9.28

2400 x 1200 x 6mm Type : R = 3.11kg  (2000x600 = 1.55kg)
2400 x 1200 x 10mm Type : R = 3.41kg (2000x600 = 1.70kg)
2400 x 1200 x 18mm Type : R = 4.09kg  (2000x600 = 2.04kg)

Is that particularly good or bad, for 1x Visaton EX60S Exciter per board?

Is it just me or is this particular material VERY heavy????

[CLS]

The horns were way better and overpowered them in each case.

And then, what makes you keep the panels?

[el`Ol]

It's interesting. Would you please share more about that measurement? 

I used a 10 cm wide and 3 mm thick board and successively added little bricks for kids. The excursion measured with a ruler didn't show any deviation from a linear behaviour. Didn't do it with the Rohacell, however.

[zygadr]

And then, what makes you keep the panels?

In case I need to make an insulated home made refridgerator

Seriously though, they have such a unique and special sound that the horns can never manage.
In my opinion, the sound of live music is within the realm of the panels more than horns or any other box or panel speaker.

[el`Ol]

One could try to get a matrix of bamboo splinters between two pieces of paper or foils.

[zygadr]

Lets not forget why the VH EPS has been so much better:
The exciter's vibrations in the crtical mids and highs (which were muted with other materials)MUST be able to be transferred from the rear of the panel to the front................efficiently.

The small micro beads of expanded plolystyrene do a magnificent job of this, that's why it sounds so good.

Do the scratch test again : grab some EPS and some cardboard and rub the back surface with your fingers while having your ear close to the front of the material. The louder the rubbing/scratching sound is, the better the material.

[CLS]

....

In my opinion, the sound of live music is within the realm of the panels more than horns or any other box or panel speaker.

I feel the same. So I dismantled the horns and put them away.

About the material and scratch test, I have a related observation. I mentioned that before -- the ways of sound distributions on the panel are different between bare foam board and the one with wooden ribs.

Maybe it's because the foam panel I use is too soft, I can detect (hear) where the exciter is when using bare board. The sound is obvious louder right at the spot. From the driving spot and the propagation outward, the vibration decreases quickly.

If the goal is 'distritrubuted-mode', then I guess such distribution is not good enough. The vibration is not evenly spreaded. I think of a point source here. 

Later on the same material panel with wooden ribs, the vibration (sound) is still the strongest at the driving spot, but much less so. The vibration along the ribs sound pretty consistent from the driving spot all the way to the ends. Now it's more of a 'line source' (one of the ribs is more like a spine, actually). Those areas away from the support of ribs are much quieter, like the way they are on bare board. Anyway, with help of ribs, generally speaking, the vibration is spreaded more evenly, to a larger area.


zygadr, I'd guess maybe this is one of the reasons you like several of them placed in line. It's pretty much like a 'line source' of my single exciter on rib (spine).


In this regard, rigidity is needed to spread the vibration more evenly. Stiffer boards would be better for this. And it probably links to the linearity test by el'Ol...   

[scorpion]

I don't know if this has been commented before but the EPS V(ery) H(igh) grade quality that zygadr describes should the same as an EPS s300 quality. The s300 quality is the kind of board people use to make their own surfboards for instance. It can withstand 300 kilo Pascals pressure over a short time. Unfortunately the smaller thickness boards like from 10 mm up to 30 mm are only produced in 1200 x 600 mm size, at least here in Sweden. The 1200 x 600 x 10 mm board will weight less than 300 grams. The cubic meter weight of this EPS quality is 40 Kg.

/Erling
 

[zygadr]

Hi Erling.
Here in Australia, the VH stands for ''V''ery ''H''ard in actual fact.
The maximum density is stated as being 30kg/m3, but I think it's the same stuff.

We can get very large sizes here though. Strange, as it seems this VH grade is hard to get anywhere else in large sizes?

CLS, you are right in the statement that a line of vertical exciters acts as a line source. From a distance you can not hear the individual exciters, but close up,you can spot the sound of each individual unit.

This is the way Podium Sound do it as well and I forget their technical explanation for the design..........something to do with a tapered horn array(or something ).

[zygadr]

NEWS FLASH!!! :

I have been contacted by the Australian Supplier of Ultra Board, and will be sent a sample piece 6mm thick. Will be an interesting test for sound quality and transmission!!

[CLS]

Everyone
While doing the tests on the foamcore I noticed something strange about the hf.
....

sedge
 

Hi,

Let's rewind a bit. This is quoted from, say, about 10 pages back...

sedge, how do you like the foamcore (with the HF 'problem' you've found)? Does it sound good?

As I search the forum by this term 'foamcore', that is the only post I can find. Don't know if anyone else is using it.

And for clarification, by 'foamcore', is the one you say composed by dense PS foam as the core with paper on both surfaces?

Until recently, I finally knew that the provider of my PS foam panel is also selling foamcore. According to the seller, foamcore is much stronger than bare PS foam. That should be a good thing for panel. Is it?

[zygadr]

It depends on what the foamcore is coated with and what type of foam used.

If it's paper, it would be doubtful that any strength is gained. The stuff I have seen in art shops covered in black paper is absolutely dreadful. The paper also kills the high frequencies.

Gatorfoam is also a type of ''foamcore'' and is very strong and rigid with it's wood fibre coatings. However, the interior is a much softer foam than VH EPS and therefore was not as good with H.F. response and sensitivity.

When we are talking about ''stronger'', you must be cautious as to what they mean by ''stronger''.
If it's more ''rigid'', that is good.
BUT!..............if it has a spongy soft interior, you will lose a lot of efficiency and high frequency information.