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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

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. 

GF equalizers owner's manual

16

owner`s manual GF equalizers © 1994 Zeck Audio

Analyzer

Mixing desk

GF 215

Constant

 

Q

2x15 Graphic EQ

-10

+10

0

Gain

Channel 2

Power on

EQ in

Low cut

-10

+10

0

Gain

Channel 1

EQ in

Low cut

25

40

63

100160250400630

1k

1.6k2.5k

4k

6.3k10k16k

25

40

63

100160250400630

1k

1.6k2.5k4k

6.3k10k16k

25

40

63

100160250400630

1k

1.6k2.5k

4k

6.3k10k16k

25

40

63

100160250400630

1k

1.6k2.5k4k

6.3k10k16k

+12

0 dB

+6
+3

+9

- 3

- 9

- 12

- 6

Clip

3 dB

6 dB

12 dB

Signal

H

E
A

D
R
O
O
M

Clip

3 dB

6 dB

12 dB

Signal

H

E
A

D
R
O
O
M

R

power

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

     

             

AP ·1800

2 x 900 W att Ster

eo Power Amp

Protect

Limit

Level

ch 1

54

48

45

42

39

36

33

30

27

24 2118 15 12

9

6

3
0

51

5760

– dB

Protect

Limit

Level

ch 2

54

48

45

42

39

36

33

30

27

24 2118 15 12

9

6

3

0

51

5760

– dB

Power

Master

Out

L

L

L

R

R

R

Input

Power amp

GF 215 / GF 230

Input

Output

Output

Measuring microphone

Содержание constant Q GF215

Страница 1: ... 10 0 Gain Channel 1 EQ in Low cut 25 40 63 100 160 250 400 630 1k 1 6k 2 5k 4k 6 3k 10k 16k 25 40 63 100 160 250 400 630 1k 1 6k 2 5k 4k 6 3k 10k 16k 25 40 63 100 160 250 400 630 1k 1 6k 2 5k 4k 6 3k 10k 16k 25 40 63 100 160 250 400 630 1k 1 6k 2 5k 4k 6 3k 10k 16k 12 0 dB 6 3 9 3 9 12 6 Clip 3 dB 6 dB 12 dB Signal H E A D R O O M Constant Q 2x30 Graphic EQ Clip 3 dB 6 dB 12 dB Signal H E A D R O...

Страница 2: ......

Страница 3: ...m paying particular attention to cords at plugs convenience receptacles and the point where they exit the Component 7 Non use Periods The power cord of the Component should be unplugged from the outlet when unused for a long period of time 8 Object and Liquid Entry Care should be taken so that objects do not fall into and liquids are not spilled into the inside of the Component 9 Damage Requiring ...

Страница 4: ...rge trimmte Bandpaßmodule und Vielfach Summierungspunkte sorgen für ein Minimum an unerwünschten Phasenverschie bungen Die Filter im GF Equalizer sind als Constant Q Bandpässe ausgelegt bei denen die Bandbreite über den ganzen Stellweg des Faders gleich bleibt Im Gegensatz zum herkömmlichen Filterdesign mit nichtkonstanter Bandbreite zei gen Zeck GF Equalizer bei Maximalstellung aller Fader nur ei...

Страница 5: ...60 250 400 630 1k 1 6k 2 5k 4k 6 3k 10k 16k 25 40 63 100 160 250 400 630 1k 1 6k 2 5k 4k 6 3k 10k 16k 25 40 63 100 160 250 400 630 1k 1 6k 2 5k 4k 6 3k 10k 16k 25 40 63 100 160 250 400 630 1k 1 6k 2 5k 4k 6 3k 10k 16k 12 0 dB 6 3 9 3 9 12 6 Clip 3 dB 6 dB 12 dB Signal H E A D R O O M Constant Q 2x30 Graphic EQ Clip 3 dB 6 dB 12 dB Signal H E A D R O O M Clip 3 dB 6 dB 12 dB Signal H E A D R O O M ...

Страница 6: ... 1 6k2 5k 4k 6 3k10k16k 25 40 63 100160250400630 1k 1 6k2 5k4k 6 3k10k16k 12 0 dB 6 3 9 3 9 12 6 Clip 3 dB 6 dB 12 dB Signal H E A D R O O M Clip 3 dB 6 dB 12 dB Signal H E A D R O O M R Mischpult power AP 1 800 2 x 900 W att Ster eo Power Amp Protect Limit Level ch 1 54 48 45 42 39 36 33 30 27 24 2118 15 12 9 6 3 0 51 5760 dB Protect Limit Level ch 2 54 48 45 42 39 36 33 30 27 24 2118 15 12 9 6 3...

Страница 7: ...ave entspricht und beim GF230 1 3 einer Oktave Die folgende Tabelle zeigt den Zusammenhang zwischen den Nennfrequen zen der einzelnen Fader den entsprechenden nächstliegenden Musiknoten und dem Frequenzbereich GF 215 GF 230 Note 25 Hz 25 Hz G2 31 Hz H2 40 Hz 40 Hz D 1 Bass 50 Hz G1 63 Hz 63 Hz H1 80 Hz D 100 Hz 100 Hz G GF 215 GF 230 Note 125 Hz H 160 Hz 160 Hz d 200Hz g tiefe Mitten 250 Hz 250 Hz...

Страница 8: ...er Equalizer richtig auf den betreffenden Raum abgestimmt Die folgende Abbildung zeigt wie ein sol cher Echtzeit Analyzer angeschlossen wird Anti Rückkopplungsfilter Wenn man die Lautstärke einer Mikrofon Beschallungsanlage ständig erhöht wird mit großer Wahrscheinlichkeit an einem bestimmten Punkt eine Rückkopplung auftreten Besonders Monitor Lautsprecher sind oft eine Quelle für Rückkopplungen d...

Страница 9: ...mit zu einem schlechteren Gesamtklang Senkt man mit einem Equalizer die störend hervortretenden Frequenzen gezielt ab so kann der Aufnahmepegel zugunsten eines dynamischeren Gesamtklanges wieder erhöht werden 5 Fehler Checkliste Die folgende Liste enthält die am häufigsten zu erwartenden Bedienungsfehler und Fehlfunktionen und die Maßnahmen zur Abhilfe Bei Auftreten einer Fehlfunktion empfiehlt es...

Страница 10: ...______________________________________________________________________________________________________________________________________________ Rauschen 95 dBm Regler in Mittelstellung EQ in 92 dBm Regler in Mittelstellung EQ in 75 dBm alle Fader am oberen Anschlag 68 dBm alle Fader am oberen Anschlag alles 22 Hz 22 kHz RMS unbew alles 22 Hz 22 kHz RMS unbew Gain Regler 10 dB to 10 dB mit 0 dB Mitt...

Страница 11: ...m paying particular attention to cords at plugs convenience receptacles and the point where they exit the Component 7 Non use Periods The power cord of the Component should be unplugged from the outlet when unused for a long period of time 8 Object and Liquid Entry Care should be taken so that objects do not fall into and liquids are not spilled into the inside of the Component 9 Damage Requiring ...

Страница 12: ...ltiple summing point circuitry phase irregularities between the frequency bands are reduced to a minimum All Zeck GF equalizers feature professional Constant Q filter technology where the bandwidth remains the same throughout the entire boost cut range of one fader Unlike most other equalizers which utilize the simpler variable Q filter design the GF equali zers display an extremely low ripple whe...

Страница 13: ...sture No user serviceable parts inside Refer servicing to qualified personnel CAUTION WARNING CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN CAUTION For continued protection against fire hazard replace only with same type and rating of fuse ATTENTION Afin de réduire le risque de feu remplacer uniquement par un fusible de même type et valeur PUSH PUSH PUSH PUSH PUSH PUSH PUSH PUSH PUSH PUSH PUSH PUSH P...

Страница 14: ...160250400630 1k 1 6k2 5k 4k 6 3k10k16k 25 40 63 100160250400630 1k 1 6k2 5k4k 6 3k10k16k 12 0 dB 6 3 9 3 9 12 6 Clip 3 dB 6 dB 12 dB Signal H E A D R O O M Clip 3 dB 6 dB 12 dB Signal H E A D R O O M R Mixing desk power AP 1 800 2 x 900 W att Ster eo Power Amp Protect Limit Level ch 1 54 48 45 42 39 36 33 30 27 24 2118 15 12 9 6 3 0 51 5760 dB Protect Limit Level ch 2 54 48 45 42 39 36 33 30 27 24...

Страница 15: ...ncies is 2 3 of an octave on the GF215 and 1 3 of an octave on the GF230 The following chart specifies the center frequencies their corresponding musical notes and frequency domains GF 215 GF 230 Note 25 Hz 25 Hz G2 31 Hz H2 40 Hz 40 Hz D 1 bass 50 Hz G1 63 Hz 63 Hz H1 80 Hz D 100 Hz 100 Hz G GF 215 GF 230 Note 125 Hz H 160 Hz 160 Hz d 200Hz g low mid 250 Hz 250 Hz h 315 Hz d 1 400 Hz 400 Hz g1 50...

Страница 16: ...ll 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 overal...

Страница 17: ...rbing resonant frequency can be attenuated which allows for an overall higher recording level and a much more balanced sound 5 Troubleshooting The following list contains the most common malfunctions and the steps that have to be taken if they should occur For quickest success follow the list in the given order until the desi red function is working If all measures should fail to succeed send the ...

Страница 18: ...in Total Harmonic Distortion THD 0 01 20 Hz 20 kHz 0 005 20 Hz 20 kHz typically Noise 95 dBm all controls flat EQ in 92 dBm all controls flat EQ in 75 dBm all faders in maximum position 68 dBm all faders in maximum position both 22 Hz 22 kHz RMS unweighted both 22 Hz 22 kHz RMS unweighted Gain control 10 dB to 10 dB with 0 dB center detent position Channel separation 60 dB 20 Hz 20 kHz Level Indic...

Страница 19: ...owner s manual GF equalizers 19 owner s manual GF equalizers 1994 Zeck Audio ...

Страница 20: ...Zeck Audio Turnhallenweg 6 D 79183 Waldkirch Tel 0 76 81 20 04 0 Fax 0 76 81 20 04 43 ...

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