Allen & Heath AP5195 用户手册
PA User Guide
27
SOURCE SELECT
Decide how you want to use the
output channels. Set the two switches according to the A and
B sources required. The switches are recessed to prevent
accidental operation once set. Use a pen or sharp object to
change their settings.
B sources required. The switches are recessed to prevent
accidental operation once set. Use a pen or sharp object to
change their settings.
Front-of-House refers to the audience listening area. It
is commonly called FOH or simply ‘house’. The house
speakers provide the PA for the audience.
speakers provide the PA for the audience.
Foldback monitors Monitors are typically wedge
shaped floor speakers or stand mounted ‘hotspot’ speakers,
headphones and earpieces used by the performers to hear
themselves and others on stage. Foldback is the term used to
describe the process of returning some signal from the console
back to the performers.
headphones and earpieces used by the performers to hear
themselves and others on stage. Foldback is the term used to
describe the process of returning some signal from the console
back to the performers.
Different output configurations The PA Series AB
outputs can be used in many different ways. Sound system
requirements vary for many reasons. You may want to run a
stereo house system with separate left and right speakers and
no monitors, or a mono system with a foldback monitor. You
may be using an external speaker processor for a bigger house
system and therefore use your PA Series AB channels for a
pair of equalised stage monitors.
requirements vary for many reasons. You may want to run a
stereo house system with separate left and right speakers and
no monitors, or a mono system with a foldback monitor. You
may be using an external speaker processor for a bigger house
system and therefore use your PA Series AB channels for a
pair of equalised stage monitors.
The Output Equalisers
Each AB output channel
features a 4-band semi-parametric EQ. This divides the audio
range into four overlapping frequency bands. Each band has a
bell shaped peak/dip response with adjustable gain and
tuneable frequency.
range into four overlapping frequency bands. Each band has a
bell shaped peak/dip response with adjustable gain and
tuneable frequency.
LF, LM,HM,HF
The lower control cuts or boosts the
frequencies around the centre point by up to 10dB. The flat
response centre position is detented to help you find it quickly.
response centre position is detented to help you find it quickly.
FREQUENCY
The upper control adjusts the centre point
frequency of the band. The width of the bell, or Q, is 1.8
measured at +10dB.
measured at +10dB.
Why the parametric output EQ? You are probably
familiar with the 7 or 9-band graphic EQ used on traditional
powered mixers. These have a similar bell shaped response
but set at fixed frequency points. The PA Series parametric
design provides much more accurate control because you can
tune each band to the exact frequency required. It also has a
tighter width per band so reducing the unwanted effect on
nearby frequencies. Used carefully you can deal with poor
room or speaker response and deal with feedback while
maintaining the fidelity of the original sound. In modern sound
engineering the parametric EQ is the professional engineer’s
choice for accurate frequency shaping.
powered mixers. These have a similar bell shaped response
but set at fixed frequency points. The PA Series parametric
design provides much more accurate control because you can
tune each band to the exact frequency required. It also has a
tighter width per band so reducing the unwanted effect on
nearby frequencies. Used carefully you can deal with poor
room or speaker response and deal with feedback while
maintaining the fidelity of the original sound. In modern sound
engineering the parametric EQ is the professional engineer’s
choice for accurate frequency shaping.
☺
Using the output equalisers The best advice is to use as
little EQ adjustment as possible, and to cut rather than boost.
Before or during sound check, start with all bands set flat with
their gain and frequency controls at mid position. Avoid the
typical ‘smiley face’ EQ that overloads the amplifiers in an
attempt to get more range from inadequate speakers. A small
amount of boost at 70Hz and 10kHz can achieve the desired
results. Using a good test source such as CD or pink noise,
listen for resonant or ‘boomy’ frequencies in the room, and
frequencies that start to feed back or ‘ring’ when microphone
gain is gradually increased. Adjust the controls to tune in to
the offending frequencies and apply only small amounts of cut.
Before or during sound check, start with all bands set flat with
their gain and frequency controls at mid position. Avoid the
typical ‘smiley face’ EQ that overloads the amplifiers in an
attempt to get more range from inadequate speakers. A small
amount of boost at 70Hz and 10kHz can achieve the desired
results. Using a good test source such as CD or pink noise,
listen for resonant or ‘boomy’ frequencies in the room, and
frequencies that start to feed back or ‘ring’ when microphone
gain is gradually increased. Adjust the controls to tune in to
the offending frequencies and apply only small amounts of cut.
10k
1kHz
100
30k
10
20Hz
200Hz
AB OUTPUT EQ
-15
-10
-5
0dB
+5
+10
+15
120Hz
2kHz
500Hz
10kHz
1.5kHz
20kHz
LF
LM
HM
HF
Experiment with the Allen
& Heath Windows™ EQ
Visualiser software. This
lets you see how the
adjustments you make
with the EQ controls can
affect the signal frequency
response.
& Heath Windows™ EQ
Visualiser software. This
lets you see how the
adjustments you make
with the EQ controls can
affect the signal frequency
response.
Download the Allen &
Heath RTA (real time
analyser) software from
our web site. This is an
invaluable tool to help you
identify and use the EQ to
correct problem room and
ringing frequencies.
Heath RTA (real time
analyser) software from
our web site. This is an
invaluable tool to help you
identify and use the EQ to
correct problem room and
ringing frequencies.
L R
+ FB2
FB1 FB1
L
R
L R
+ FB2
FB1 FB1
L R
+ FB2
FB1 FB1
L
R
L
R