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features overview
3
rear panel
16
Low cut switch
This switch is used to activate the LOW CUT filter for the corresponding channel. It is
again a push-push type switch, requiring a small "tool" to activate. The IN position routes
the input signals through the 40 Hz LOW CUT filter, while the OUT position bypasses
the filter. This filter will cut extremely low frequencies, protecting speakers from the pos-
sibility of over-excursion. The filter low-frequency rolloff is 12 dB per octave. The LOW
CUT filter for each channel will function independently of the crossover function to be
discussed next.
17
Crossover switch (150 Hz XOVER)
This switch is used to activate the 150 Hz crossover for the corresponding channel. It is
also a push-push type switch and requires a small "tool" to activate. The CPX offers two
150 Hz crossovers. These are specially designed features that enhance the response of
most loudspeakers in a typical bi-amped application. Rather than just having a flat out-
put curve, these crossovers use special filters to tailor the response and provide a flat
acoustical output. This type of crossover "sounds" more natural than conventional "state-
variable" type crossovers.
With the switch IN, the input signals are routed through the crossover, and the low fre-
quencies are automatically sent to the corresponding channel. At the same time, the
high frequencies are sent to the HIGH OUT (19) jack and must then be patched to
INPUT of the other channel of this amplifier or to another amplifier input to complete the
bi-amped system. Additionally, the low frequencies are sent to the THRU/LOW OUT
(18) jack, and can be patched to other amplifier inputs to permit even larger systems.
With the switch OUT the crossover is defeated, and the input signal is routed directly to
the respective power amp channel. The crossover frequency is fixed at 150 Hz and
cannot be changed. The crossover configuration is a 4-pole Linkwitz-Riley approxima-
tion.
18
THRU/LOW Out jacks
As per previous crossover discussion, this ¼" jack supplies low-frequency out signals
from the activated crossover for patching to additional power amplifier inputs, providing
added flexibility in larger bi-amped systems. When the crossover function is not activat-
ed, this jack converts to a THRU function, where the output of the electronically bal-
anced input circuitry is supplied to this jack. The THRU function provides the means to
patch a full range input signal to the other input of this amplifier (parallel mode), or to
other amp inputs in the same rack. This function allows one balanced mixer feed to be
connected to the amp via the desired balanced input connector (XLR, ¼", Barrier), and
then further distributed locally. Regardless of the crossover switch position, this ¼" jack
provides an unbalanced (tip/sleeve) output to be patched with single conductor shielded
cables.
19
High Out jacks
Again, as per previous crossover discussion, this ¼" jack supplies high frequency out
signals from the activated crossover for patching to this amplifier and/or additional power
amplifier inputs. Unlike the low-frequency crossover output, that is automatically routed
to the associated channel, the high-frequency output signal must be patched to some
suitable input in order to complete the bi-amped system. This ¼" jack also provides an
unbalanced (tip/sleeve) output to be patched with single-conductor shielded cables.
