An interesting page with great pics:

http://translate.google.com/translate?hl=e...net/betonboxen/

Great idea. I suppose concrete is an excellent sound absorbing material so nothing gets out of the sides and backs to muddy up the image. The port probably doesn't get all sorts of reflected energy, again to the benefit of imaging.

The concrete doesn't absorb. It pushes it out. There have been people building concrete speakers for ages. Just not in the main stream.

I'm basing this on the idea that concrete walls are a better sound barrier than wood walls. So, rather than absorbing better, concrete reflects better? Drivers better be primo or IMO, those concrete speakers have the potential to be bright.

i agree. but also if you port the woofer will mellow the sound out.