Don Keele's Circular-Arc Speakers
The Chicago Show was my second opportunity to hear the unique circular-arc line array speakers designed by legendary audio engineer Don Keele, who was for many years the speaker reviewer at the long-gone Audio
magazine. The 5'-tall CBT36 covers a 36° vertical arc, and with its 72 ¾" tweeters and 18 3.5" midrange units, all sourced from Dayton, projects a tailored wavefront that both allows for a very wide sweet spot from where a stereo image can be perceived and doesn't fall off with distance in the usual manner. The speakers used a DEQX digital crossover and were being driven by an Acurus amplifier. They were operating down to 45Hz, below which a subwoofer took over.
A pair of CBT36s costs $1980 as a kit from Parts Express (price to eventually rise to $2999.99) or fully assembled for $6000 from Audio Artistry. The smaller Selah speakers in the photo were not being demmed but cover a 45° arc and cost $8995/pair fully assembled.
A video illustrating the CBT36's unique radiation characteristic can be found at http://www.youtube.com/watch?v=McbuV1jSOs8.