User manual

C4-SUB (2.0E)
C4 and B2-SUB systems, 4:1 ratio
C4 and B2-SUB systems driven from C4-OUT
connection, 2:1 ratio
For an E-PAC version 3, the configuration is set via a front panel
digital rotary encoder in conjunction with an LCD.
The E-PAC can drive a single C4-SUB cabinet at an output power of
300 watts. We do not recommend that two C4-SUB cabinets are
driven in LO IMP mode as the 6 dB reduction in input level to the
loudspeakers results in no gain in acoustical output.
Stacking notes
The horn chamber, which transmits frequencies ranging from approx.
70 Hz to 180 Hz, is located in the bottom half of the cabinet. A reflex
system which covers frequencies below this range (tuning frequency:
53 Hz) is located at the top of the front panel. The system has be
tuned to ensure the correct operation of C4-SUB used on its own.
When arraying C4-SUB's there is therefore no point in creating an
enlarged horn opening by stacking the cabinets horn to horn.
If the C4-SUB system is placed directly on the floor, we advise
turning the cabinet upside down so that floor coupling helps to
increase the effective baffle area for the reflex port. If C4-SUB
systems are stacked two high, the upper C4-SUB can be turned
upside down so that both reflex ports lie directly on top of each
other. If cabinets are stacked three or more high they can be used in
their upright positions - with their reflex ports to the top.
Combination of C4-SUB and B2 systems
The C4-SUB operates down to 50 Hz (

5 dB). However, some
applications require frequencies below this cutoff. Using the B2
subwoofer can not only give the required LF extension but also
increase the low frequency headroom of the C4 system.
Setting the B2 controller module to INFRA by a front panel switch
configures the B2 system to operate in the 50 Hz area covering a
one octave band from 32 Hz to 68 Hz (

5 dB).
A single B2 system delivers enough low end bass to supplement the
output of four C4-SUB cabinets. When C4-SUB and B2-SUB's are
operated in an identical acoustic environment (e.g. in one cluster on
the ground), with controllers set to the same level, the combined
systems low frequency limit is 37 Hz (

5 dB).
The system headroom can be increased in applications using less
than four C4-SUB's to one B2 subwoofer by raising the lower cut off
frequency of the C4-SUB's. A dedicated balanced output (C4-OUT) is
provided on the rear panel of the B2 controller for driving the C4
system under these conditions.
The C4-OUT introduces a relatively narrow-band signal attenuation
around 50 Hz, which raises the lower frequency limit of the C4-SUB's
to around 60 Hz. This shift is not acoustically critical since the region
affected is covered by the B2 system. The response of the TOP
cabinets in the system will remain the same whether their controllers
(C4-TOP-CO or C7-TOP-CO) are fed directly or by the C4-OUT
signal.
In applications where most of the C4-SUB's are flown, they are
deprived of the additional acoustic gain due to ground coupling. To
maintain a tight bass sound the level of the ground stacked
B2-SUB's should be turned down respectively. (approx. -6 dB). The
increased system headroom derived from the use of the C4-OUT can
be an advatage when used to drive the flown system.