Introducing the CBT36


The CBT36 is a floor-standing 5ft. - tall two-way curved line array that provides sonic accuracy and soundfield coverage control surpassing even the finest high-end loudspeakers

Based upon declassified military research on constant-Beamwidth underwater sound Transducers (CBT) originated by the US Navy, the system was designed and implemented by Marshall Kay and Don Keele of Audio Artistry, Inc.

Each array features 18 Dayton Audio 3.5" ND Series drivers along with 72 specially designed 1/2" aluminum dome tweeters, and is available in kit form as well as a fully assembled product. The CBT36 will redefine your expectations of audio reproduction system performance!


View Papers and Presentations

US Navy Papers
Don Keele
Patents
B&W 801 vs. CBT36 Ground-Plane Measurements

Posters
Brief Overview of CBT Theory
Front Pages of Keele and US Navy CBT Papers
Vertical Sound Field Simulations

Power Point Presentations

John Atkinson's Stereophile comments after visiting Audio Artistry's demo room at RMAF 2011
Don Keele & the Constant Directivity CBT36 Speaker

2011 RMAF coverage of Audio Artistry’s CBT36 by Senior Reviewer Doug Schroeder of Dagogo
http://dagogo.com/View-Article.asp?hArticle=938
(and please scroll down to the end).

CBT36 Vertical-Sound Field Simulations
Poster we displayed in our demo room at Rocky Mountain Audio Fest 2011

Sound Field Simulations

Floyd Toole quotes from his book:
"Sound Reproduction, Loud Speakers and Rooms"

Floyd Toole Quotes

Other Controlled Directivity Designs
http://www.linkwitzlab.com/Constant_directivity_louds.htm

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Order Your CBT36 Kit Today!

Parts Express

CBT36 complete kit


 

 


CBT36 FLOOR-STANDING CBT CIRCULAR.ARC
HIGH-END LOUDSPEAKER LINE ARRAY



A REVOLUTIONARY NEW SYSTEM BASED ON CBT THEORY:
Marshall Kay and Don Keele of Audio Artistry brought their concept to reality in conjunction with electronics supplier Parts Express and its Dayton Audio brand of loudspeaker components to create the CBT36, the world's first broadband constant directivity (CD) loudspeaker system for the home. The CBT36 system provides extremely even coverage and flat frequency response at all locations in the listening room.

CBT THEORY:
CBT, which stands for Constant Beamwidth Transducer, is a loudspeaker line array technology pioneered by Don Keele in six Audio Engineering Society technical papers, and is based on unclassified military underwater sound research. See
http://www.dbkeele.com/CBT.php for in-depth information on the CBT concepts.

SYSTEM DESCRIPTION:

Each CBT36 contains 18 each 3-1/2" full-range drivers, used as mid woofers, and 72 each 3/4" diameter wide-band tweeters, that are crossed over at 1 kHz. Initially, the system will only be available in a bi-amped version but later a passive crossover may be offered. The drivers are mounted on a front panel that has a 36° circular-arc with the system standing about five feet tall and a width of about 7 inches, and a depth at the base of about 25 inches.

DRIVERS:
The 3-1/2" drivers are Dayton Audio's ND91, which were designed specifically for the CBT36 system. The ND91 utilizes a Neo-Balanced 1" underhung motor that is capable of over 10 mm of peak excursion and features a shorting ring to help keep distortion under control. The 3/4" diameter tweeters are also made by Dayton Audio, and are mounted on pc boards in groups of four to ease assembly and optimize center to center spacing.

SPECIFICALLY DESIGNED TO ELIMINATE THE DETRIMENTAL EFFECTS OF FLOOR
REFLECTIONS:

The CBT36 has been specifically designed to operate over a reflective ground plane and does not suffer from destructive floor-bounce effects. The curved line array of 72 tweeters extends all the way down to the floor to take advantage of the ground-plane acoustic reflection. Effectively the floor provides a reflective surface that acoustically extends the array below floor level and thus creates an array that is over 10 feet tall and controls vertical coverage and directivity down to below 160 Hz!

THE VERTICAL AND HORIZONTAL COVERAGE OF THE CBT36 GREATLY REDUCES
CEILING AND WALL REFLECTIONS:

The above-the-floor vertical coverage of the CBT36 is a narrow 28º which is extremely stable with frequency. This greatly reduces ceiling reflections as compared to a typical box style system. In addition, the horizontal coverage which is very broad narrows as you go around the side of the system, which also significantly minimizes side wall reflections.

EXTREMELY EVEN COVERAGE WITH NO SWEET-SPOT LISTENING AXIS:

The system has extremely well-behaved and smooth coverage from locations well above the array to points even down at floor level, and at distances from directly in front of the speaker to points in the rear of the listening room. The horizontal coverage is extremely broad and uniform even out to plus-minus 90 degrees. The CBT36's variation of loudness with, distance is also very unique. At standing height, the system's volume level hardly changes over a range from directly in front of the system to points 10 feet away!

MAXIMUM SPL AND DISTORTION:
The system can be played extremely loud and remains very clean and effortless at all levels. The large number of drivers minimizes distortion, and driven with powerful amplifiers the system can generate very-high instantaneous peaks.

SYSTEM REQUIREMENTS:

The system must be bi-amped and requires a DSP-based speaker processor along with two stereo power amplifiers. For extended bass response below 45 Hz, one or two powerful subwoofers are required.

 



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