Concrete Audio Speakers...Speaker Enclosures made out of Concrete ?..

You would think aluminium billets would ring like a bell but they are used often. Concrete is a too general term for a number of different mixes which obviously have different characteristics. Which would be best for speakers, I don't know. As previously stated concrete has been used in transmission line speakers. I still rate concrete as a great idea for speaker plinths and equipment stands, as for speakers I think it certainly would be worth investigating further

"I don't take anything for granite..."  (Sorry, and Yes, too easy...)

I made a pair of ceramic speakers (porcelain) a long while ago....fun concept, lousy in use....*shrug*  Resonates...but they were small....

Fibre concrete will allow thinner walls, saving weight.  Flip side requires very careful design as the stronger structure will start to resonate.

Foamed concrete hasn't been tried to my knowledge.  But may have the same issues as ceramics.  The mass reduces, the weight as well....allowing for the excitation of the enclosure.....

...and foamed materials generally require casting.....big$....

Kenjit

So if a speaker is shaped like a bell it will ring like a bell?
Does that imply a speaker shaped like a tuna fish will sound in tuna? 

"Does that imply a speaker shaped like a tuna fish will sound in tuna?"

How will the speaker shaped by kenjit sound?

So if a speaker is shaped like a bell it will ring like a bell?

It IS a bell. Its a bell with drivers in them. Not a good idea.