|The Central Indiana Section of the Audio Engineering Society is pleased to announce our July meeting, to be held Thursday July 18, 2013 featuring Don Keele speaking on the topic of “Introduction to CBT Loudspeaker Arrays.”
Come out and hear Don Keele talk about his loudspeaker line arrays based on CBT technology. He has been an ardent advocate and evangelist for the concepts for over ten years and believes the CBT know-how can vastly improve the sound field uniformity of existing line arrays and conventional loudspeaker systems. Don will discuss the background and history of CBT arrays and will describe and discuss the measurement and simulation results of several CBT line arrays including the Audio Artistry CBT36 high-end home loudspeaker which is sold in an inexpensive DIY kit form by Parts Express (http://www.parts-express.com/CBT36/) and finished form by Audio Artistry. The CBT36 system will be setup for listening.
We have invited percussionist John Marque (http://johnmarque.com/) to participate in a live-versus-recorded drum-kit shootout with the pair of CBT36 systems.
CBT, which stands for “Constant Beamwidth Transducer,” is a term originated by the U.S. military in a series of three un-classified Naval Research Lab ASA papers published in the late 70s and early 80s. These papers describe spherical-cap underwater transducers with special frequency-independent “Legendre” shading that provide extremely-uniform broadband coverage without the need for any special or complex signal processing. Don applied the technology to loudspeaker arrays in a series of six AES papers between 2000 and 2010 and some of the technology is now in the public domain. The CBT arrays provide a broadband constant-directivity 3D sound field that is incredibly uniform and well behaved with frequency at all distances from very close to far away. The vertical beamwidth control and coverage of the CBT line arrays often exceeds even the finest constant-directivity pro horns.
ABOUT THIS MONTH’S SPEAKER:
Mr. Keele holds two BS degrees in EE and Physics from California State Polytechnic University and an MSEE degree from Brigham Young University where he minored in acoustics. He has presented and published over 40 technical papers on loudspeaker design and measurement methods and other related topics, among them the paper for which he won the AES Publication Award, “Low-Frequency Loudspeaker Assessment by Nearfield Sound-Pressure Measurement”. He is a frequent speaker at AES section meetings and workshops, has chaired several AES technical paper sessions, and is a past member of the AES review board. Mr. Keele is a past member of the AES Board of Governors and is past Vice President, Central Region USA/Canada of the AES. Mr. Keele received the TEF Richard C. Heyser Award in 2001. In 2002, he received a Scientific and Engineering Academy Award from the Academy of Motion Picture Arts and Sciences for work he did on cinema constant-directivity loudspeakers. In 2011 he received the ALMA Beryllium Lifetime Achievement Award for contributions to the loudspeaker industry.
Date: July 18, 2013 at 7:30pm