The Perfect Plywood for Open Baffle speakers??

[Type 1]

39mm Structural Eucalyptus Hardwood Plywood!

It doesn’t get much stronger than that!!

[HdB]

I would think the 11ply/25mm would be strong/rigid enough- I  didn't know you could get it this thick -  it's not the lightest or cheapest plywood around ...-

[Type 1]

Thanks Hdb,

Ive never made an Open baffle speaker, but would imagine that the Baffle is very likely to vibrate. 
I would think 25mm would be the bare minimum..

 

[THOMO]

Made in Laos.Does that make it loasy?

Surely we can make eucalypt ply here?We have plenty of plantations  and regrowth but it seems that is shipped overseas as woodchip rather than value adding to it here.

[Type 1]

Thanks Thomo!

so, there are still a few plywood mills about in Australia but most of them make pine plywood… Carter Holt Hervey in Myrtleford Vic and Austral in Brisbane, to name two.

The Eucalyptus grown in Laos is a Hybrid species.. combining the Density of Red River Gum from Australia with the tropical Rainbow Gum from Papua Guinea and north to create an Extremely hard fast growing timber!

It is processed by a Swedish company in Laos to produce a Birch Alternative! 
The density is similar, but I suspect that the Eucalyptus sound is a bit brighter and the Birch sound is a little mellower..

Hopefully that helps…

[THOMO]

We used to be able to get karri ply which was fantastic.Our government here in WA has shut down logging of native species here which includes karri regrowth .Which is just plantations and ideal for rotary cut ply..An area next to it that was planted  with pines following clearfelling can be used but not the area replanted with karri! The stupidity of our politicians is mind boggling sometimes!

[Type 1]

Hi THOMO!

the golden years of timber in Australia are far behind us. Global politics will wear us out..

either work with what we have.. or have faith in a better world!!

[HdB]

I think AustralPly up in Brisbane are still manufacturing Hoop Ply in various thicknesses - also might be a company down here (Melb) still making it too.

 

Vibrations?  Not sure about how significant this would be assuming you avoid physical resinances (bracing, added weights, etc)

There's a 'school-of-thought' that isolates the actual driver from any physical contact with the baffles so it's quite a consideration - personally, I've just bui;lt the baffles strong, heavy and damped but it's quite possible that light baffles and baffle radiations could be beneficial just like some commercial speakers

[THOMO]

8 hours ago, HdB said:

I think AustralPly up in Brisbane are still manufacturing Hoop Ply in various thicknesses - also might be a company down here (Melb) still making it too.

 

Vibrations?  Not sure about how significant this would be assuming you avoid physical resinances (bracing, added weights, etc)

There's a 'school-of-thought' that isolates the actual driver from any physical contact with the baffles so it's quite a consideration - personally, I've just bui;lt the baffles strong, heavy and damped but it's quite possible that light baffles and baffle radiations could be beneficial just like some commercial speakers

There is a Youtube test of various  materials including beech ply,pine ply,MDF ,constrained layer and solid hardwood.The surprising thing there was that there was very little difference between beech ply and pine ply and not that much difference to MDF.MDF does tend to have some resonances higher up in the frequency range.The MDF 'honk" some people mention? But the real surprise was the solid hardwood  which was less resonant than the ply and MDF.

But the material used is far less important than bracing and damping.

Edited June 22, 2024 by THOMO

[SPR08Y]

https://www.bigrivergroup.com.au/product/hardwood-plywood/