B-52 ACTPRO Active Systems - Instruction Manual
THE BEAUTY OF POWER
ACTPRO
11
speaker. If this is the case, reduce the input signal
strength and increase the gain of the loudspeaker
amplifier.
Always observe the red LIMIT LED on the ampli-
fier panel. This LED illuminates when signal is clip-
ping and compressor-limiter is activated. All ACTPRO
amplifiers employ sophisticated limiter circuitry, which
monitors signal condition at both LF and HF amplifiers
(LF only on ACTPRO18S) and compresses output sig-
nal when necessary to protect woofer and compres-
sion driver from damages. Limiter circuitry works very
unobtrusively, you may not even notice when it acti-
vates. It may prompt you to push input signal more,
it is good practice for the red LIMIT LEDs to blink
occasionally but not constantly. Constant illumination
of the LIMIT LED indicates a gross overloading condi-
tion and should be avoided. Reduce the signal level if
LIMIT LED lights constantly or blinks constantly!
Note that LEVEL Control has a range of 30dB. It
does not attenuate output signal to zero. LEVEL control
on ACTPRO loudspeakers is used to set optimal maxi-
mum level for performance, not for constant control
of sound volume. Your mixer’s master volume control
should be used for this purpose.
NOTE that LEVEL control provides about 12dB at-
tenuation in middle position. You will find that in most
cases the best sound (lowest distortions and lowest
noise) will be achieved when LEVEL Control is set
somewhere between middle and FCW position.
6. LOW CUT SWITCH
(ACTPRO12M, ACTPRO15, ACTPRO1515)
Found beneath the LEVEL control, this small slider
switch engages or disengages the 100Hz 18db/
Octave Low Cut filter. Switch the filter OFF when not
using subwoofers in the system. Switch the filter ON
when you are connecting subwoofers. This will enable
your subwoofer-equipped system to operate properly
and allow the full range loudspeakers to provide im-
proved clarity in the mid and high-range frequencies.
NOTE that when you connect ACTPRO full-range
active loudspeaker to HP outputs of ACTPRO18S
subwoofer, DO NOT engage LOW-CUT switch on
full-range loudspeaker. Input signal for your full-range
loudspeaker has already been processed by ACT-
PRO18S’s circuitry.
ACTPRO12M:
We recommend switching the filter
ON for the best sound clarity. If using as a floor moni-
tor, turn the filter ON for improved vocal range clarity
and to reduce low frequency build-up on stage.
7. OUTPUT CONNECTIONS
All Full-range models have one XLR output connector
marked OUTPUT. The output connector is wired in
parallel with the input, allowing connection of multiple
enclosures in a “daisy-chain” fashion. The
ACTPRO18S0 has two sets of output connectors,
one set (left and right) for full-range outputs (wired in
parallel with inputs) and one set (left and right) for
high-pass outputs.
ACTPRO12M, ACTPRO15, ACTPRO1515
Insert the XLR connector into the jack marked OUT-
PUT. Connect the other end of the cable to the input of
the next audio device, such as another ACTPRO full
range active loudspeaker.
ACTPRO-18S OUTPUT (Full Range)
Use the outputs marked OUTPUT (Full Range) (left
and/or Right) when you are connecting to other ACT-
PRO speakers and/or to other powered loudspeakers
that enable full-range audio or if they feature their
own low frequency filtering.
HP OUTPUTS:
Use the outputs marked HP OUTPUT
(Left and/or Right) when you are connecting other
ACTPRO and/or other powered loudspeakers that
DO NOT feature low frequency filtering or when the
low frequency roll off is desired. DO NOT use the
HP OUTPUT connectors for connecting other pow-
ered subwoofer loudspeakers - use the OUTPUT (Full
Range) line outs instead. Make sure to power OFF
any ACTPRO and/or other powered loudspeaker
connected to the HP OUTPUT before turning off the
ACTPRO subwoofer power. If done correctly, this will
ACTPRO AMPLIFIER REAR CONTROLS
