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SIGNAL INPUT
MIC, CD etc. TO MIXER
MIXER
OUTPUT
INPUT TO
GRAPHIC EQUALISER
OUTPUTS FROM GRAPHIC
EQUALISERTO CROSSOVER
INPUTS TO CROSSOVER
SEPARATE
HIGH/MID
AND LOW
OUTPUTS TO
AMPLIFIER(S)
FROM
CROSSOVER
INPUTS TO AMPLIFIER(S)
SEPARATE
LOW
SPEAKER
OUTPUT TO
LOW
FREQUENCY
SPEAKER
FROM
AMPLIFIER
SEPARATE
HIGH/MID
SPEAKER
OUTPUT TO
HIGH/MID
SPEAKER
FROM
AMPLIFIER
TYPICAL WIRING DIAGRAM FOR THE WPG - 315/331 SERIES CROSSOVER IN SYSTEM SETUP
equaliser use. There are three types of feedback, i)
feedback paths direct from the speakers, ii) feedback from
early reflections and iii) feedback from diffused
reverberation.The simplest way to cure type (i) feedback
is to re-direct the loudspeakers (front of house and
monitors) away from the microphone(s) so that the signal
picked up is too small to cause howl. Type (ii) feedback
can be more difficult to control by speaker re-direction.
Type (iii) feedback can be controlled by careful placement
and some trial and error movements of the loudspeakers
may cure this. This is nearly impossible at low frequency,
since the aiming of an omni-directional frequency source
(low,bass) is not possible These initial simple methods are
not always successful. This is where the graphic equaliser
can achieve beneficial, quick results. The feedback signal
can be located and ‘notched’ out by locating the frequency
that is most likely causing the howl and applying cut
(reduction) of level at this frequency. Eventually the
problem frequency(s) will be found and feedback cured.
There may be feedback occurring at two or more
frequencies. The same procedure will stop the feedback.
By matching the feedback note with the notes on a
keyboard or guitar and knowing the relationship of
frequency with musical notes the howl can be matched
and the band reduced, so if the howl matched the note ‘A’
you would reduce the slider 4.0 kHz as A = 4.40 kHz.
Monitor Equalisation
With amplified instruments on stage the monitor sound
can become muddy and unintelligible. The equaliser can
be inserted in between the mixer monitor output and the
monitor amplifier and be used to tailor the sound of the
monitor to cut through the onstage sound. Normally a
suitable vocal sound will be obtained if the response
above 3kHz and below 500Hz is rolled off.
Shaping Equalisation (creative)
This is where the the equaliser can be used either in the
studio or on stage to emphasise a specific tonal quality of
an instrument or sound source to create a new sound.