EX12 USER’S GUIDE
P. 7
The EX12 Control Panel
The EX12 features an easy to use rear control panel
featuring audio input and output, level control, LED
status lights and a low pass filter that can be engaged
when the loudspeaker is used as a stage monitoring device.
Audio Input and Output
The EX12 uses a balanced, female XLR connector
for the audio input connector, and a male XLR con-
nector to provide through output signal. The through
output connector, wired in parallel to the audio input,
will continue to provide the input signal if the EX12 is
turned off. The audio input circuit presents a 20 kOhm
balanced input impedance to a three-pin XLR connec-
tor with the following connectors:
Pin 1 - Ground
Pin 2 - Signal (+)
Pin 3 - Signal (-)
Case - Earth (AC) ground and chassis
Audio signal can be daisy-chained using the through
output connector on the input panel. A single source
can drive multiple EX12 speakers with a paralleled
input loop. If you are driving multiple EX12’s in an ar -
ray, make certain that the source device can drive the
total load impedance presented by the paralleled input
circuit of the array.
The audio source must be capable of producing a
minimum of 20 dB volts (10 volts rms into 600 ohms)
to produce the maximum peak SPL over the operating
bandwidth of the loudspeaker. To avoid distortion from
the source, make sure the source equipment provides
an adequate drive circuit design for the total paralleled
load impedance presented by the array. The input
impedance for a single loudspeaker is 20 kOhms. If
“n” represents the number of EX12 loudspeakers in
a system, paralleling the inputs of n loudspeakers will
produce a balanced input load of 20 kOhms divided by “n”.
NOTE:
Most source equipment is safe for
driving loads no smaller than 10 times the
source’s output impedance. For example, cascad-
ing an array of 10 units consisting of EX12 speak -
ers produces an input impedance of 2000 ohms
(20kOhms divided by 10). The source equipment
should have output impedance of 200 ohms or less.
This is also true when connecting EX12’s in parallel
(loop out) with other KV2 Audio amplifiers and active
speakers and subwoofers.
TIP:
If the loudspeaker produces noises
such as hiss and popping, disconnect the
audio cable from the loudspeaker, if the noise stops,
then most likely the problem is not with the loud-
speaker. Check the audio cable, source, and AC
power for the source of the problem.
NOTE:
Ensure that all cabling carrying sig-
nal to multiple amplifiers and active speaker
systems is wired correctly. Make sure that the polar-
ity has not been reversed. Reversed polarity can
cause severe degradation in frequency response and
can also impact the dispersion characteristics of the
speaker.
Amplifiers and Acoustic Filters
The EX12 is powered by two separate power ampli -
fiers specifically designed and optimized for the low
frequency and high frequency drivers. The control sys-
tem in the EX12 processes the audio signal through a
series of electronic filters and circuits providing equal-
ization, crossover filters, phase adjustment, thermal
and overdrive protection.
The EX12 employs a protection system based on
rms limiting of the amplifiers. This type of protection
strategy allows the speaker to operate safely under
overload conditions. When the rms “limiter” engages,
the output level of both amplifiers is reduced to a safe
CHAPTER 2: AUDIO SIGNAL
Through output
Main input
MAIN INPUT
POWER ON/
LIMITER
THROUGH OUTPUT
90Hz
MONITOR FILT
LL ER
LEVEL
OFF
ON
0
+
6dB
–
6dB
SIGNAL /
THERMAL
EX12 Rear panel
