I have heard good things about Omega Loudspeakers.
I have heard the Reference 3A's and thought they were special.
Another option that comes to mind is a Voigt Pipe such as TWL uses. The Cain & Cain Abby is a comericially available product.
There are other DIY options as well. The Zigmahornet is one particulary interesting DIY project.
Here is another DIY loudspeaker built by Jerry Seigel. I am not aware of the efficiency of this design.
I have heard the Reference 3A's and thought they were special.
Another option that comes to mind is a Voigt Pipe such as TWL uses. The Cain & Cain Abby is a comericially available product.
There are other DIY options as well. The Zigmahornet is one particulary interesting DIY project.
Here is another DIY loudspeaker built by Jerry Seigel. I am not aware of the efficiency of this design.