am I crazy? granite for OB baffle

[sqlkev]

Since I work with granite, I think the fabrication can be done. But what about the stands and back support for it? any ideas?

I'm thinking of the front baffle of .75" granite and maybe 2-3 layers of mdf behind it. Granite is extremely heavy so I'm thinking of a safe way to make it stand without falling on anyone.

max baffle width should be around 24", height is undetermined (have no simulated the drivers with edge yet)

[Zen Mod]

Originally posted by sqlkev
Since I work with granite, I think the fabrication can be done. But what about the stands and back support for it? any ideas?

I'm thinking of the front baffle of .75" granite and maybe 2-3 layers of mdf behind it. Granite is extremely heavy so I'm thinking of a safe way to make it stand without falling on anyone.

max baffle width should be around 24", height is undetermined (have no simulated the drivers with edge yet)

excellent idea, even if not new

make frame of steel tubes (1"x1" ),along with "foot" frame ;

I think that mdf layer isn't needed

[dublin78]

Nice idea. I have been thinking of making some OBs out of concrete using moulds. This way I can make the base and wings (butrusses) in one piece.

The thought of a 24" wide, 3/4" thick, ???" high granite slab falling over scares me. Sure you could build something that would ensure its stability, but I suspect that any solution would detract from your beautiful granite.

Perhaps you could cut a narrow rectangle and insert a nice piece of hardwood through to act as a rear "leg". The weight of the granite would support the structure (assuming it is going to tilt backwards slightly. Also, the juxtaposition of the wood and granite would work visually. I am not sure how strong the granite would be if used like this, though.

[dublin78]

sqlkev
I am struggling to attach a diagram of what I mean.
If you email me, I will send you a copy, and perhaps you might post it for me.

[Nanook]

but so are most of us here

a couple of caveats though.. and a couple of ideas...

although dense, granite does transmit waves at a very high rate. Because it is very smooth,(I am assuming honed or cut into a smooth slab), it will most likely behave as glass in baffles, so do a search for glass baffled loudspeakers. I think the diffraction may be an issue. Some consider glass to sound "bright" or "brittle"

Because of the nature of OBs, it is not required. Energy storeage is minimized in lightweight materials. Heavier materials have the potential to store and release larger amplitudes of energy in a manner that may not be linear.
And if the drivers are isolated ftom the baffle there will be essentially "zero" energy transmitted to the baffle.

an idea: I think Naim had a boxed loudspeaker where the driver was actually isolated from the enclosure via a stand alone metal mount. So make a stand for the driver without a baffle at the required height. Make a baffle that stands isolated from the driver and driver stand. Make it out of wood , cause I have never heard a musical instrument before.

Maybe not a technical answer, but more of a "gut reaction". I'm not (nor do I think I will ever ) be convinced that granite is suitable. And regardless of the ability to work with it, It will still caost you something to purchase the material.

[dublin78]

although dense, granite does transmit waves at a very high rate.

I had not considered this.

What about concrete? I have heard of people making cabinets out of concrete moulds in the past, seemingly with success.

[chrisb]

you've "never heard a musical instrument before" - I think you mean made from granite?

(IOW, from stone, not "while .....d ", 'cause that's never happened )

FWIW, a few years ago, I heard a pair of gorgeously crafted multiway speakers made from cored basalt, and utilizing all SEAS drivers (Excel series , IIRC)

As stunning as they looked, the sound was quite simply weird - simultaneously dead and harsh, if that makes sense.

[Rudolf]

Originally posted by sqlkev
Since I work with granite, I think the fabrication can be done. But what about the stands and back support for it? any ideas?

Granite is extremely heavy so I'm thinking of a safe way to make it stand without falling on anyone.

If you are into minimalism, how about tilting the slab some degrees back and supporting it with two steel rods:

[dublin78]

EG from post No.3

[Scottmoose]

Gilbert Briggs fooled about with stone for OB use back in the 1950s. He shifted back to a sand-filled ply structure not so much for sonic reasons but because he refused on principle to lug around anything that weighed almost as much as he did.