13
POWERLINX PLM-4 MIXER/PREAMPLIFIER
Installation
Before applying power to the system, insure that all audio connections are properly
terminated and all level controls are set to minimum.
For optimum performance
,
the PLM-4 should be connected to the PowerLinx controller through its balanced XLR output
to the controller's balanced Phoenix-type inputs (Belden 82761 or equivalent). As a stand-alone unit the PLM-4 may be
connected to the balanced or unbalanced input of an audio system amplifier.
A microphone with an on/off switch is recommended so it can be left in the "Off" position when not in use for
announcements. In this way, background noise in the vicinity of the microphone won't be heard through the system and
won't trigger the ducking feature. To a void feedback, be sure not to place your microphone too close to your audio sys-
tem's loudspeakers, and use shielded cables for all audio connections.
SET-UP
1) Plug the AC adaptor into the
+9-15V AC/DC
input on the rear of the PLM-4 and then into a power outlet.
Turn on the power to the PLM-4 and your other equipment.
2)
Set the
MASTER
control to about mid position.
3)
Adjust the
STEREO 1, 2,
and
3
level controls on the PLM-4 for your music playback source(s) to comfortable
listening levels.
4)
Set your
MIC
level control to a suitable level for announcements.
5) Select your preferred ducking setting. The three-position
DUCKING
switch is located below the microphone
level control. You can select "
NONE
" for no ducking, "
DIM
" for an automatic 10 dB level reduction of the back
ground music while speaking into the microphone or "
MUTE
" to shut the music off completely while you'r
e
,
speaking into the microphone.
.
6) If you chose
DIM
or
MUTE
, adjust the
SENS
. trim with a small screwdriver. Set it so that speaking into the
microphone in a normal voice triggers ducking but whispering or rustling papers nearby doesn't. Now if you
,
wish to make an announcement, the background music volume will be reduced while you speak, and will
automatically increase to its previous level after the announcement ends.
7)
The
MASTER
level control should now be adjusted to provide a suitable level to your PLC4.1 or other following
audio equipment. This level should be as high as possible for best noise characteristics but not so high as to
overdrive the following inputs. Usually a position of 5 to 7 is optimum.
8) If any hum or buzz is noted in your audio systems output, try switching the GND LIFT switch. Note that ground
loops or other interferences may occur at any point in the chain of your equipment.
Since the PLM-4 is an end-user adjustable device the mix may be readjusted at any time. However the MASTER setting
,
should be carefully made and retained as it has a direct effect on the headroom, audio quality and system protection of
,
the PLA305 and its associated loudspeakers.
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