Yorkville PGM8 - Manuel (Page 10)

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8. L/R Main EQ
This is a stereo 7-band EQ on the output of the MAIN fader. The EQ’s adjustment range is +/-12 dB
with frequency centers at one-octave intervals from 125 Hz to 8 kHz.
Use the Main EQ during a sound check to carefully adjust the main speaker response (you
shouldn’t have any radical boosts). It is also useful for minimizing feedback, but remember
that stage monitor speakers are most often the cause of your feedback problems. Naturally,
stage monitor feedback will also be heard out the main speakers at the mixer station, which
can lead you to the illusion that the main system is the cause.
When setting the Main EQ, do not automatically go to a smiling curve as with a home
stereo – this will cost your system both headroom and gain before feedback. Initially,
keep the EQ curve as close to flat (all sliders at center) as possible, then make neces-
sary minor adjustments as required during the sound check to cut feedback frequencies.
When feedback is heard first turn down the MON fader. To reduce the possibility of the
main speakers causing the feedback cautiously turn up the Main fader to the onset of
feedback. Try to guess the frequency of the ringing tone. Reduce the Main EQ fader
closest to the frequency of the feedback. You should only need to reduce the fader to
about -3dB on the front panel EQ scale. Cautiously turn up the Main fader a little more to
the onset of feedback. Try to guess the frequency of the 2nd ringing tone which will most
likely be different than the first feedback frequency. Reduce the Main EQ fader closest to
the frequency of the feedback. Again you should only need to reduce the Main EQ fader
to about -3dB on the front panel EQ scale.
Typically there are about three major feedback frequencies that you can compen-
sate for with the Main EQ. Now with the main fader placed in your performance
gain position slowly turn up the MON fader to obtain enough monitor volume with-
out causing feedback.
9. Phones Level
The Phones level control adjusts the stereo audio level to the headphones plugged into
the Phones jack. The audio signal for the headphones is post Main EQ so that you can
hear exactly the audio signal on the Main Out phone and Main Out XLR jacks.
The Phones (headphones) jack is a stereo jack compatible with headphones having an
impedance down to 8 ohms but we recommend for best performance using headphones
with an impedance of 80 ohms or higher.
10. Break Switch
The Break switch is a great feature. When the Break switch is pressed on and the
Break LED is blinking the audio signals from channels 1 to 8 are muted. While the
Break switch is on you can play music through the Media In jacks. Great for when
the band goes on break, or while showing a video during a presentation muting room
noise picked up by the vocal microphones.
11. VU-Meter
The VU-Meter indicates the post Main EQ left and right audio levels. A good operating
level is when the music peaks light up the 0dB LEDs. Having the yellow +3dB and +6dB
LEDs flash occasionally is acceptable but you do not want the red +10dB LEDs coming on
as this indicates the possibility of clipping.
Top Panel Output Jacks
The Main Out, Mon Out and EFX Send phone jacks on the top panel are TRS (balanced
tip ring sleeve configuration) output jacks. Use them to connect to balanced and
unbalanced audio inputs.
The Stereo Rtn jacks are TRS balanced input jacks. You can connect to the balanced or
unbalanced outputs of audio equipment.
The Phones (headphones) jack is a stereo jack compatible with headphones with an
impedance down to 8 ohms but we recommend for best performance using headphones with
an impedance of 80 ohms or higher.
Keep the Main Speakers
between mics and audience
to minimize feedback
DO NOT place Main
Speakers in back of
the stage!!