Concrete Spheres

[mikee12345]

Hello i saw some home made concrete spherical enclosures for 4inch speakers,,

does anyone have the link???


i would like to make them sometime,they have quite a flat response ,has anyone built any??

can one make a sphere out of MDF slices?

[7V]

I tend to find that concrete is too hard and reflective for the mid-range, although good for bass.

You could make a sphere out of MDF slices, although it wouldn't be easy. I have just built speakers with interesting internal and external shapes. The link is: Construction Photos for Seventh Veil Nonsuch 4. The principle is the same but you would have to make the sizes vary vertically and then sand down to a sphere.

Good luck
Steve

[NH7RO]

Do a google search for "Darren Kuzma"--I think that should take you to his concrete speaker site (though you might be looking for a different one).
I built some concrete speakers 10 years ago that sound terrific--I used a pair of Dynaudio 17W75EXT 4 ohm mid/woofers with some Linaeum tweets on top. The enclosures are basically truncated tubes with the baffle for the Dyn's made up of 5 pieces of oval MDF glued with Liquid Nails (and I cut out random oval sections and filled the cavities with lead shot and Liquid Nails). Inside, the walls are somewhat irregular and I applied gobs of lead shot/LN to smooth out the "corners" and then covered interior with black hole pad and stuffed with long hair wool...
So while I agree that bass is best best out of concrete (amazing what these 6.5'' woofers can do!), the midrange doesn't seem to suffer much because of my damping treatments (so far as I can surmise).
Nonetheless, I'm also toying with the idea of trying an egg-shaped or "nOrh-shaped" enclosure using many sections of MDF with some other drivers (for further fun/experimentation/DIY mania!). Good luck, have fun with concrete and I'll stay tuned to this thread. Cheers,
Jeff

[Andy G]

with a bit of thinking , a lathe etc, yep, easy to build a sphere,

This isn't a sphere, btw, but you get the drift !!!!!

http://users.tpg.com.au/users/gradds/pics/stack2.JPG

[7V]

Originally posted by NH7RO
Inside, the walls are somewhat irregular and I applied gobs of lead shot/LN to smooth out the "corners" and then covered interior with black hole pad and stuffed with long hair wool...
So while I agree that bass is best best out of concrete (amazing what these 6.5'' woofers can do!), the midrange doesn't seem to suffer much because of my damping treatments (so far as I can surmise

Well, that should do it Jeff. I used silicone on the walls in the upper part of my Nonsuch full-range cabinets and stuck long-haired wool (very organic/new age) on to the silicone.

Steve

[Peter Daniel]

Steve,

What are you using for a gasket under the driver when mounting it to the enclosure? I believe it has quite an influence on a sound and recently I was seriously considering few choices, but not sure which one would be the best? Some of my choices: rubber, cork, cardboard, O-ring, softwood or mounting direct?

[7V]

Originally posted by Peter Daniel
Steve,

What are you using for a gasket under the driver when mounting it to the enclosure?

I use neoprine with the full-range drivers and nothing with the bass drivers. Fits the 'bass cabinet hard/mid cabinet soft' theory.

I haven't really had time to actually listen to the alternatives yet in the latest system. On the other hand, if it ain't broke ...

Steve

[Peter Daniel]

My way of thinking was also that for better bass, drivers should be mounted directly, with no gasket. I used cork on my midbass driver, hoping it would be best of both approaches.

[pinkmouse]

A long time ago, I actually used vibration isolating mounts , as used for machinery to mount speakers in boxes, with the void filled with sorbothane. It did improve the definition of the boxes slightly, but as a construction technique it was far too fiddly and time consuming to get right, so I gave up on it.

But one day, I may try again!