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PA-CP

User Guide

SOURCE SELECT

Decide how you want to use the

amplifiers. 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.

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.

Foldback monitors

Monitors are wedge shaped and

‘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.

Different amplifier configurations

The

PA Series

amplifiers 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 external amplifiers for a bigger house system and
therefore use your

PA Series

amps for a pair of stage

monitors. You may be using powered speakers throughout
and so apply the amps to a different task altogether.

The Output Equalisers

Each AB amplifier 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.

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.

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.

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.

☺

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.

10k

1kHz

100

30k

20Hz

200Hz

AB OUTPUT EQ

-15

-10

-5

0dB

+10