English
11
3 CT 115
CT 115 Fullrange Cabinet
The CT 115 is a passive speaker cabinet that may
also be configured in biamp mode. Offering an
extended low-frequency range and featuring a
dual-purpose housing, it can serve as a FOH
speaker as well as a stage monitor. The CT 115’s
hallmarks include speech intelligibility, extra-
ordinary phase linearity, and wide dynamic range.
Its HF horn has been optimized using the BEM
(Boundary Element Method) for precise directivity
and optimal clustering without phase
cancellations.
The CT 115 was developed principally for fullrange
sound reinforcement applications over short to
medium throw distances, without an additional
subwoofer. When used as a stage monitor (Shape
switch set to Monitor), the CT 115 cuts through
even on loud stages and is able to handle kick
drum and bass signals. The CT 115 is available in
left and right versions for symmetrical monitoring
arrays. The CT 118 Sub subwoofer is the
recommended enhancement for setting up power-
ful, two-way active systems.
The CT 115 may be operated in passive or biamp
mode with or without a controller. For the best
audio results, it is recommended that this
enclosure be operated with the HK AUDIO
®
DSM
2060 Controller or HK AUDIO
®
Digital Field Con-
troller (DFC) in combination with a DFC network.
Application scenarios: Stand-alone fullrange
system, near-field sound reinforcement for
applications demanding high SPL, for example, as
an FOH mid-/high-range unit in live clubs, an
ancillary front fill for COHEDRA™ systems, a
mid/high-range unit for side or drum fills and for
monitoring on larger stages.
Enclosure design and mechanical appointments:
The CT 115’s enclosure is constructed of 18-mm,
13-ply birch plywood. Shaped to serve dual
functions, the housing is 45 cm wide, 69.5 cm
high and 39 cm deep, and weighs 33 kg. The sur-
face is coated with black water-repellent acrylic
lacquer. The front baffle is protected by a steel
grille. The enclosure’s panels are equipped with a
total of two Aeroquip rigging tracks and two
threaded M10 bushings. The CT 115 may be flown
horizontally as well as vertically. An optionally
available mounting yoke attaches to the Aeroquip
track on the top panel to rig and fly the cabinet.
Recessed handles are located on the top and bot-
tom panels of the housing. An HK AUDIO Triple-
Tilt™ Pole Mount Adapter is on the bottom panel;
it allows the cabinet to be mounted on a tripod at
three different tilt angles ( +5°, -3° or -10°).
Electrical and acoustical data:
The CT 115 features a direct-loaded 15“ neo-
dymium speaker and a 1.4" B&C high-frequency
driver with a 60° x 40° CD horn. Courtesy of the
housings’ foursquare design, the horn may be ro-
tated to 40° x 60° inside the housing. The CT 115’s
frequency response ranges from 65 Hz to 16 kHz
(+/- 3 dB). Nominal power handling is 600 watts
RMS at 8 ohms. Axial sensitivity is 106 dB,
measured under half-space conditions at 1 watt
@1m. Maximum SPL measured under the same
conditions at a distance of one meter is 134 dB.
Connectors:
Connectors, the Passive/Biamp switch and the
Shape switch are located out of harm’s way on a
countersunk panel on the back of the CT 115. This
panel offers two Speakon NL 4 ports. Both ports’
four pins are wired in parallel. Pin assignments in
passive mode are pin 1+ = mid/high +, 1- =
mid/high -, 2+ = sub +, 2- = sub 2-. In biamp
mode, the HF signal is routed via pin 1+ / 1-. The
LF/MF signal is routed via pin 2+ / 2- of the
Speakon connectors.
3.1 Directivity, CT 115
Figure 13: Vertical directivity CT 115
Figure 14: Horizontal directivity CT 115
The charts depict horizontal and vertical
directivity at various frequencies. These data were
ascertained using -6 dB and -12 dB sound
pressure isobars.
3.2 Adjusting Directivity
The HF horn’s mounting yoke is square, enabling
the horn to be rotated 90°. To do this, please
detach the front grille by loosening the screws
(M4 x 25 countersunk) on the side panels using a
Phillips screwdriver. Then remove the four M4x25
screws holding the horn in place. Now you can
rotate the horn by 90°.
3.3 Shape and Mode Switches
The CT 115 features a Shape switch on its rear
panel. This switch optimizes the passive cross-
over, enabling the cabinet to be used as an FOH
speaker or as a (passive) monitor. When the
switch is set to the Monitor position, the 1. 4"
driver’s dampening factor is reduced to ensure
the speakers cuts through on loud stages.
The Mode switch configures the CT 115 for
passive or bi-amp modes. In bi-amp mode, the
15" speaker’s passive crossover is deactivated,
though the 1.4" driver’s slight pre-dampening –
accomplished using passive components -
remains enabled. The HK AUDIO
®
Controller
DSM 2060 is equipped with a factory preset filter
for biamp mode. When configuring the enclosure
for biamp mode, set the Shape switch to the
position labeled Monitor!
Figure 15: Monitor and
Shape switches
3.4 Specifications, CT 115
Engineered to render audio signals with consis-
tently natural sound and tremendous dynamic
range, this professional two-way speaker system
features a BEM-optimized HF horn for precise
directivity and optimal clustering without phase
cancellations. It is designed for use as a fullrange
speaker or a mid/high unit in combination with
the CT 118 Sub or HK AUDIO COHEDRA™ sub-
woofers. It is loaded with a 15" neodymium low-/
midrange woofer mounted in a precision-tuned
bass reflex enclosure, as well as a 1.4" high-fre-
quency driver with a 3" voice coil connected to a
