Epique CBT24 Line Array Speaker System PairThis breakthrough technology is based on declassified U.S. Navy underwater sound research. CBT, which stands for Constant Beamwidth Transducers and is a term coined by the military in the late 70s and represented in eight Audio Engineering Society (AES) technical papers. Don Keele Jr. one of the most distinguished audio engineers of the last four decades, initially brought this concept to reality by creating the CBT36 line array kit - the world’s first broadband constant directivity (CD) loudspeaker system for the home.
Now, Epique by Dayton Audio presents the CBT24, the latest in the CBT line of premium speakers. The CBT24 system provides extremely even coverage and flat frequency response at all locations in the listening room. The system not only provides even coverage at all points up-down, right-left, and near-far; but is linear-phase and time-aligned at all these points as well! These desired characteristics are unattainable in a conventional stereo speaker pair and will redefine your expectations of audio reproduction system performance. The CBT24 is available as a finished system pair and as a kit for the DIY/cost conscience buyers.
Read Daniel Kumin's review of the CBT24 in the August 2017 issue of Sound and Vision ( www.SoundAndVision.com ): Dayton Audio Epique CBT24 Speaker System Review
System description
Each CBT24 contains 24, 2-1/2" full-range drivers. These drivers have been designed specifically for this new system. Since these are full-range speakers, there is no need for crossovers that can cause phasing issues. The drivers are mounted on a front panel that has a 36° circular-arc, with the system standing about five ft. tall and a width of only 3-1/2 inches, giving a unique contemporary and artistic appearance. The system provides an extremely well-controlled narrow vertical coverage of 27° that greatly reduces ceiling reflections. The system requires only a single stereo amplifier; an optional equalizer or DSP Crossover/Processor/EQ and subwoofer(s) can also be added if desired.
Drivers
The 2-1/2" drivers are Dayton Audio's ND64-16, which were designed specifically for the CBT24 system. The ND64-16 is truly a full-range driver and capable of over 6 mm of peak-to-peak excursion. It features a dual Neo-Balanced magnet structure, a 3/4" CCAW voice coil, and a copper sleeve to minimize distortion. The driver features a rising high frequency response that partially compensates for the inherent roll-off of a CBT array and includes unique design features that widen its high-frequency coverage. These drivers are mounted very close together to take the advantage of mutual coupling -- another criterion of the CBT technology.
Designed specifically to eliminate the detrimental effects of floor reflections
The CBT24 is intended to operate over a reflective ground plane and does not suffer from destructive floor-bounce effects. The curved line array of 24 drivers 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 ft. tall and controls vertical coverage and directivity down to below 160 Hz!
The vertical and horizontal coverage of the CBT24 greatly reduces ceiling and wall reflections
Above-the-floor, vertical coverage of the CBT24 is a narrow 28° that 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 CBT24 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 or minus 90°. The CBT24'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!
System Requirements
The system works quite well on its own without EQ from below 100 hz to 8Khz. However the system would benefit from additional subwoofer(s) and/or an EQ. With an EQ the system can be used on its own with reasonable bass extension down to 45 Hz. The system will require a subwoofer(s) for powerful deep bass. For the ultimate audio experience employing an active DSP, either it be from a separate DSP “only” unit or a receiver that has DSP functions, is recommended. A DSP unit supplies capability to either extend the low end of the system down to 45 Hz for operation without a subwoofer or to cross the system over to a subwoofer below 80 Hz. The DSP processor also provides touchup EQ to flatten the system’s overall response and to extend the system’s response out to the limits of hearing. By employing a large number of drivers the system can be played extremely loud and remains very clean and effortless at all levels.
About the designer
D.B. (Don) Keele Jr. is one of the preeminent audio engineers of the last four decades. His work is focused especially on the characteristics of sound as it leaves its source, and its subsequent behavior while filling the listening environment. He is particularly well known for his groundbreaking (and patented) Constant Directivity and Bi-Radial high frequency horn concepts. He has worked for a number of companies including, Electro-Voice, JBL, Klipsch, Crown and Harman International . Mr. Keele holds eight patents with topics including constant directivity loudspeaker horns, loudspeaker arrays, and signal processing.
He is an Audio Engineering Fellow (AES) as well as a 2016 AES Gold Medal recipient. 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. Mr. Keele holds two BS degrees (EE and Physics) and an MSEE with minor in acoustics. Since 1972, he has presented and published 50 technical papers. Licensed under U.S. Patent numbers 7,684,574 and 7,826,622 from Harman International Industries, Incorporated.
Specifications: • Recommended amplifier power: 50 to 250 watts RMS • Impedance: 4 ohms • Frequency response: 80-20,000 Hz • Dimensions: 60" H x 3.5" W x 25" D (at base).
