Zeck constant Q GF 215 Bedienungsanleitung Seite 16

GF equalizers owner's manual
with a loud musical signal, but leave some dB headroom for
unexpected level peaks. However, don't worry if the 'Peak' LED
flickers shortly from time to time at the very loudest passages,
as the GF equalizer still offers some headroom above clipping
indication.
In a studio environment, where precise fine-tuning of sounds by
ear is required, it can also be a good idea to set the gain con-
trol, so that the output loudness of the equalizer is the same in
'EQ on' and bypass mode, helping the user to A/B-compare his
equalized sound with the original signal.
General rules for equalizing
In the first place, changing of EQ settings should always be
done carefully and slowly to avoid the danger of annoying if not
hazardous feedback surprises. If you are using your ear as a
reference, bear in mind that the human ear adapts to the new
sound curve and accepts it as a new reference. Therefore, it is
always a good idea to compare the equalized sound with the
original signal from time to time to avoid over-equalization,
which will result in a rather unnatural sound. Instead of boosting
a certain frequency band, first try to achieve the same effect by
attenuating other frequencies, as this generally results in a
more natural sound.
Room equalization
Most acoustical environments, especially rooms, tend to over-
emphasize, or more likely, 'swallow' certain frequencies for phy-
sical reasons. To achieve a linear sound reproduction in spite
of this phenomenon, a graphic equalizer can be used to cut or
boost these suspicious frequencies. First, a real-time analyzer
should be used to detect holes or peaks in the room's frequen-
cy response, which can then be compensated for by the equali-
zer, until the analyzer displays a linear frequency curve. The
Mixing desk
Master
Out
L R
Input
25 40 63 100160250400630 1k 1.6k2.5k 4k 6.3k10k16k
Channel 1
+12 Clip H
E
+9 3 dB A
D
R
6 dB
+6 O
O
+3 12 dB M
Signal
0 dB
- 3
- 6
- 9
- 12
EQ in
25 40 63 100160250400630 1k 1.6k2.5k 4k 6.3k10k16k
GF 215 / GF 230
power
Protect Protect
24 2118 15 12 24 2118 15 12
27 27
9 Limit 9 Limit
30 30
33 6 Level 33 6 Level
3 3
36 36
0 0
39 39
– dB – dB
42 42
45 45
ch 1 ch 2
48 ∞ 48 ∞
51 51
54 5760 54 5760
Power amp
16
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25 40 63 100160250400630 1k 1.6k2.5k4k 6.3k10k16k
Channel 2
0 0
Clip H
E
R
3 dB A
D
R
6 dB
O
GF 2 1 5
O
12 dB M
-10 +10 -10 +10
Q
Gain Signal Gain Constant
2x15 Graphic EQ
Power on
Low cut EQ in Low cut
25 40 63 100160250400630 1k 1.6k2.5k4k 6.3k10k16k
Output
R
L
Input
Power
AP ·1 800
2 x 900 W att Ster eo Power Amp
sound system is now tuned to the 'house curve' of this particu-
lar room. The following illustration shows, how the analyzer and
equalizer have to be set up for room equalization.
Feedback elimination
If the gain of a sound reinforcement system with microphones
is constantly increased, at some point feedback will occur.
Monitor systems are especially sensitive to feedback due to
their position near microphones, especially when angled
towards them. As a rule, feedback starts at one single frequen-
cy, which can be determined by an analyzer or with the help of
a musical instrument and the table on page 13. Reducing the
gain of this particular frequency on the equalizer will stop the
feedback and allow the overall gain of the system to be raised,
resulting in a higher sound pressure without feedback. When
the next frequency starts to feed back, this procedure can be
repeated to achieve even more feedback-free amplification.
Recording
- Simulated stereo: a simulated stereo signal can be created
from a monaural signal by routing the signal through both
channels in parallel. Boost and cut alternate bands on chan-
nel A and, in reverse order, on channel B and have the chan-
nels panned left and right in the mix.
- Noise reduction: hiss on cassette recordings can be reduced
by boosting all frequencies above 6.3 kHz when making
recordings. When playing the tape back, cut the same fre-
quencies on the EQ for the same amount, resulting in less
hiss. Old but proven effect devices can be improved in their
noise behaviour almost the same way: route the input of the
effect device through channel A and the output through chan-
nel B. Boost the highs on channel A and cut the same fre-
quencies on channel B.
L
Output
R
Measuring microphone
Analyzer
owner`s manual GF equalizers © 1994 Zeck Audio