Allen & Heath AP5195 用户手册

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PA User Guide 
25 
 
MONO OUT LEVEL
   This is the master 
control for the console mono output.  The LR mix is 
summed after the LR faders to produce the mono 
signal.  Use the control to adjust the balance 
between the LR and MONO feeds.  Once set, use 
the LR fader as the house volume control affecting 
the LR and MONO outputs.  The control ranges from 
fully off to +6dB boost above its unity gain position. 
SUB FILTER
   Press to switch in the 100Hz low 
pass filter.  This is a built-in crossover filter to 
condition the mono output for driving a sub bass 
amplifier/speaker.  Frequencies above 100Hz are 
rolled off at 12dB per octave.  The switch is recessed 
to prevent accidental operation once set.  Use a pen 
or sharp object to change its position. 
   Sub bass speakers   are large coned drivers, 
typically 15” or 18”, built into reasonably large 
cabinets designed to reproduce the very low 
frequencies.  They are referred to as ‘subs’.  They 
are not used by themselves.  Smaller speakers often 
referred to as the ‘tops’ are added to reproduce the 
mid and high frequencies.  Without a filter the sub 
can reproduce frequencies as high as 500Hz or 
more.  This can cause a sub/top combination to 
sound  ‘boxy’  or  ‘muddy’.    For  this  reason  a  filter  is 
added to cut frequencies above the required 
frequency range, usually around 100Hz.  This filter 
may be built into the sub cabinet, its amplifier or a 
separate crossover unit.  The PA Series adds the 
switchable 100Hz filter for situations where no filter is 
provided.  Check your sub speaker instructions to 
see if it is needed. 
 
Background Music (BGM)
   The console 
provides a facility for playing an independently 
controlled stereo music source such as CD through 
the house speakers while the main LR faders are off.  
This is ideal during walk in or while taking a break 
during intermission. 
BGM
   Routes the 2-track input to the LR outputs 
after the master fader but before the mute switch.  
This means that the signal  is  not  affected  by  the 
fader but is turned off when MUTE is pressed.  A 
large green LED lights when BGM is selected. 
2TRK TO LR
   Controls the level of the 2 track 
signal to the LR output from fully off to +6dB boost 
above ‘0’.  It has no effect if the BGM switch is off. 
  To avoid feedback do not use BGM if you 
are using the 2-track input to monitor a recording 
being made from the LR mix. 
 
2TRK OUT
   Selects the 2-track output feed to 
be  pre  or  post  LR  faders.    It  affects  both  the 
analogue and digital (SPDIF) outputs.  In its normal 
up position the source follows the fader movements.  
When the switch is pressed, the LR faders can be 
used as the house PA volume control without 
affecting the recording.  The switch is recessed to 
prevent accidental operation once set.  Use a pen or 
sharp object to select its position. 
 
Console Monitor
      The  PA Series monitor 
system lets you listen to the various console signals 
using headphones, and check levels on two large 
LED bar meters.  Using the monitor does not affect 
the main outputs. 
HEADPHONES LEVEL
      Controls  the 
volume of the selected monitor source in the 
headphones.  It does not affect the level displayed 
on the meters. 
  WARNING:  To prevent damage to your 
hearing start with the headphones level set to 
minimum.  Avoid continued high listening levels 
in the headphones or any other earpiece. 
LR/2TRK
   Selects the normal headphones and 
meter monitor source.  In its  up position the post-
fade  LR  signal  is  selected.    When  pressed,  the  2-
track input is monitored.  Pressing any PFL or AFL 
button automatically overrides this selection. 
PFL/AFL LED
   A large red LED indicator lights 
to warn you when a PFL or AFL has been selected. 
METERS
   A pair of 12 segment LED bar meters 
displays the level of the selected monitor source.  
The LR mix and 2-track input are displayed in stereo, 
and PFL/AFL signals in mono on both bars. 
  
PFL  stands for Pre-Fade Listen.  It is used on 
the inputs so that you can check the signal while the 
channel is muted or its fader down. 
  
AFL  stands for After Fade Listen.  It is used 
on the outputs so that you can check the signal 
exactly as it is at the console outputs. 
  Using PFL and AFL   Use PFL to check sound 
quality and the channel gain setting when plugging 
in different sources or when you suspect a change 
or problem with a particular signal.  Use AFL when 
you need to check one of the foldback mixes.  You 
should hear the signal in your headphones and see 
its level displayed on the console meters.  Adjust the 
gain and mix controls so that the meters read an 
average ‘0’ with loudest peaks no more than ‘+6’. 
 
10k
1kHz
100
30k
-35
-40
10
-30
-25
-20
-15
-10
-5
0dB
+5
+10
100Hz
MONO SUB FILTER