[sedge]

Ossi
This is not an easy one to answer ,my 3x2ft ply panels played full range in all three rooms down stairs and even outside on the patio ,and sounded good.
When I tried to play my 220cm x 80cm x 25mm eps  panel in the front room ,the room cancellations in the 100hz to 300hz region made them sound odd ,they sounded great when listened to from the next room,as if someone was actually playing in their,so the cancellations were only heard when listening in the room ,weird.
I have not tried 25mm xps so cannot comment ,but if it has the same dynamics as the eps ,the larger panels give a larger scale to the sound ,drum solos are outstanding,unbelievable in fact,the smaller panels can't quite do it ,but it's close .
But to do this I still have to use a LF driver (i use TLs)of some sort to help cancel the cancellations in the 100hz to 300hz region ,I usually run the large and the smaller panels down to about 80hz,and run the TLS up to about 300hz,this has worked for me for a long time,xo ing the panels at 300hz did not sound as good to me ,the panels are still putting out a lot of sound even if you can't hear it because of the cancellations.
I do not run any of my panel types down into the LF region ,take the sound track from the film,the dark knight ,the low frequencies on this sound track are exciter destroying! So be warned.
Hope this is of help even if it does not answer how large a panel must be to produce full range .
Steve

[sedge]

ossi
you mentioned the ply low end response ,this is a quick pic of my 3x2ft ply panel response at 12ft distance, it had to be quick because of the road noise at this time of day

steve

[OB_Newbie]

Hmmm, Steve... that sure is some elevated high frequencies?!?   At that distance my panels roll off slowly (but don't sound rolled off due to the DML panel's power response) at about 9KHz. 

Is this in a really reflective room??

[osssyvan]

Steve,

My 40w exciter are still fairing quite well. I will stress test them for you . I think i have to test big panels at some point to experience them. Difficulty to find a place and transport for them.

I wonder what causes the cancellations on foam. Did you same issues with other materials?

Have you tried super thin ply? I guess it would be floppy but don't know how they would sound otherwise.

My current list of materials to test is:
Big xps panels
Big ply panels
Reboard
Carbon fiber composite
Glass fiber composite

I'll still have to get that mic so I can share my experiences better

-ossi

[Gary.M]

Steve could you let me know what thickness of ply that is, and also what sort of ply? e.g is it a regular quality 3 ply, 5 ply, or a high quality birch, etc?

ossi
you mentioned the ply low end response ,this is a quick pic of my 3x2ft ply panel response at 12ft distance, it had to be quick because of the road noise at this time of day

steve

[sedge]

OB_newbie
If you look back at pages 127 you will see the response in a different room which is about the same in the hf , also on page 126 you will see the response of the 6ft panel , I scratched my head for a bit ,then remembered the exciter was stuck on with double sided tape, I have always said you can loose a lot of hf if you use tape,and also detail.
Notice from the side pic of the panel the hf holds up.
The 2x3ftx3mm panel has a very smooth easy on the ear sound ,not offensive in any way,even with the peak in the hf which isn't very noticeable,to my ears anyway!
A little too easy going for my tastes, but good all the same.
Steve

[sedge]

Gary.m
I've loaded win 10 ,and now my computer is up the creek,so can't post pics , the panel is 3ply hard wood 3.6 but my tape measure says it is 3mm ,that's all I know.
It's two thin sheets glued either side of a thicker sheet 2mm or so .
Steve

[Gary.M]

Gary.m
I've loaded win 10 ,and now my computer is up the creek,so can't post pics , the panel is 3ply hard wood 3.6 but my tape measure says it is 3mm ,that's all I know.
It's two thin sheets glued either side of a thicker sheet 2mm or so .
Steve

OK, thanks. When I read my way through this thread I can't recall if anyone had tried bamboo ply? It is available in a thickness of 3mm and appears to be highly uniform, and rigid.

[OB_Newbie]

Hey Gary... and good to see you here on AC!

Bamboo would be stiff for sure... have to research the weight.  I wish bamboo ply was available locally or I would certainly like to give it a spin.  I wonder if it wouldn't be over damped however... would be my only concern.

Cheers!
Rich

[OB_Newbie]

Like Sedge, I dug out my 1/16" ply panels with the Thrusters after losing an Ultra exciter on one of my standard XPS panels and have to say I am enjoying them more than what I remember.  They don't do anything wrong, are easy to listen too and just lose a bit of detail and high freq. extension to the XPS panels.

Good stuff and happy I went back for another listen.  These are untreated and with no edge support to keep the thin ply from flopping so there is more performance to be had from these thin ply panels!

[sedge]

Gary.m
I don't remember anyone on this site using bamboo ply, I would be more worried that the panel would be overly lively on the thinner ply , but until you try It ,you can never tell .
can't imagine what a bamboo panel would look like ,what sizes do they come in?
steve

[guest42212]

> These are untreated and with no edge support to keep the thin ply from flopping
> so there is more performance to be had from these thin ply panels!

So the panel is supported only by it's connection to the exciter ?

[OB_Newbie]

These are resting on stands with a medium weight felt trifolded so pretty well damped on the bottom edge.  Top edge resting on thick rubber bands near the top corners of the panel but it isn't very rigid so it does make very light contact with felt padded rest that the rubber bands are attached to.

View of front and back:

[Gary.M]

Bamboo Ply is widely used in the architectural industry and in building. It can be bought by the sheet.

http://www.plyboo.com/products/category/plywood-veneer

Also it is available from Ponoko, one of the new digital maker suppliers and they will cut it to your drawing file. Only thing is they don't go as large as I want to try. I've asked them what is limiting their size offerings.

https://www.ponoko.com/

[guest42212]

These are resting on stands with a medium weight felt trifolded so pretty well damped on the bottom edge.  Top edge resting on thick rubber bands near the top corners of the panel but it isn't very rigid so it does make very light contact with felt padded rest that the rubber bands are attached to.

View of front and back:

Hyper Thanks ..... !!!!!!!! .......
So far I tried a piece of plastic ......
But it sounds like plastic .....
Maybe wood is more transparent ??

[OB_Newbie]

What type of plastic did you use?

[Odal3]

OB - those look great!!! Congrats

[guest42212]

The slide in insert that shuts a doggy door ...........

[sweenz27]

Hey guys, I'm a newbie here, but am intrigued with these sound exciters!  I have been playing around a bit with these and experimented with putting 2 exciters on the back of an acoustic guitar and the result was pretty awesome!  I don't think it's audiophile grade by any means, but sounds a lot better than a lot of normal speakers.  There is a natural sound and when there is acoustic guitar playing you almost think the guitar itself is playing!  Here is a demo on youtube: https://youtu.be/GRJdIv_zvag

Let me know what you think, and what could improve it!
Thanks!

[richidoo]

Hey Tom, welcome to AudioCircle.
Interesting experiment! Maybe try damping the strings, see if that cleans it up a bit.