CBT36K Assembly Manual
Page
74
of 89
14.1.7. 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 ±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 12 feet away!
14.1.8. System is Phase Linear and Time Aligned at all Frontal and Lateral Points:
One big advantage of circular-arc CBT arrays is that they are both phase linear and time aligned at all
locations in front of and to the sides of the array. This behavior is not only exhibited at a magic listening
“sweet spot” in front of the array but at other locations including ones above the array, to points on the
floor, to points very close and far from the array, and at extreme off-axis horizontal locations around the
sides of the array. On multi-way systems, such as the CBT36, this depends of course on the crossover
that is used with the system. It must be adjusted to provide linear phase and time alignment at least at
one point in front of the array. All other locations will then fall in line.
14.1.9. 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. See later section in this appendix titled: “CBT36 Sensitivity and Maximum
SPL” for detailed information.
14.1.10. System Requirements:
The system must be bi-amped and requires an active DSP-based loudspeaker crossover/EQ along with
two stereo power amplifiers. For extended bass response below 45 Hz, one or two powerful subwoofers
are required.
NOTE:
The CBT36 can’t be used without an active crossover/EQ.
The CBT36 can’t easily
be crossed over passively because of the inherent non-flat frequency-response characteristic of curved-
arc CBT arrays (see section titled “CBT36 Power Rolloff” in Appendix 2 for more information). A passive
crossover is not available for the CBT36.
For this initial CBT36 product launch, we recommend two DSP loudspeaker crossover/EQ units for the
CBT36, one relatively inexpensive (the Behringer DCX2496) and the other a more-expensive high-end
unit (the DEQX HDP-Express). We have extensive experience with both units; the Behringer unit was
used in all our CBT36 product development and the DEQX unit was used when we demonstrated the
CBT36s at several audio shows.
Here are more details on both these DSP speaker processor units:
The Behringer: DCX2496 ULTRADRIVE PRO Digital Crossover:
(
http://www.behringer.com/EN/Products/DCX2496.aspx
) available from Parts Express:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=248669&utm_source=googleps
This manual includes detailed setup instructions for this unit.
and the DEQX HDP-Express speaker/room calibration processor:
(
http://www.benchmarkmedia.com/dac/dac1-hdr
) available factory direct from DEQX:
http://www.deqx.com/purchase.php
).
Two big advantages of using the more-expensive DEQX processor is that it will do automatic correction of
phase/time loudspeaker errors, and will also do automatic room acoustic corrections. The DCX2496 will
also correct phase/time loudspeaker errors with its delay capabilities, but it requires manual setup.
