Yamaha Q2031B User manual

YAMAHA
GRAPHIC EQUALIZER
EGALISEUR GRAPHIQUE
GRAPHISCHER EQUALIZER
ECUALIZADOR GRAFICO
Q2031B
GQ1031C
GQ2015A
OPERATION MANUAL
MANUEL D'INSTRUCTIONS
BEDIENUNGSANLEITUNG
MANUAL DE INSTRUCCIONES

PRECAUTIONS
1. Avoid Excessive Heat, Humidity, Dust and
Vibration
Keep the unit away from locations where it is likely to be
exposed to high temperatures or humidity — such as near
radiators, stoves, etc. Also avoid locations which are subject
to excessive dust accumulation or vibration which could cause
mechanical damage.
2. Avoid Physical Shocks
strong physical shocks to the unit can cause damage. Handle
it with care.
3. Do Not Open The Case Or Attempt Repairs
Or Modifications Yourself
This product contains no user-serviceable parts. Refer all
maintenance to qualified Yamaha service personnel. Open¬
ing the case and/or tampering with the interna! circuitry will
void the warranty.
4. Make Sure Power Is Off Before Making Or
Removing Connections
Always turn the power OFF prior to connecting or discon¬
necting cables. This is important to prevent damage to the
unit itself as well as other connected equipment.
5. Handie Cables Carefully
Always plug and unplug cables ™ including the AC cord —
by gripping the connector, not the cord.
6. Clean With a Soft Dry Cloth
Never use solvents such as benzine or thinner to clean the
unit. Wipe clean with a soft, dry cloth.
7. Always Use the Correct Power Supply
Make sure that the power supply voltage specified on the
rear panel matches your local AC mains supply. Also make
sure that the AC mains supply can deliver more than enough
current to handle all equipment used in your system.
IMPORTANT NOTICE FOR THE UNITED KINGDOM
Connecting the Plug and Cord
IMPORTANT. The wires in this mains lead are coloured in accordance with the fol¬
lowing code:
BLUE :NEUTRAL
BROWN :L1VE
As the colours of the wires in the mains lead of this apparatus may not correspond
with the coloured markings identifying the terminals in your plug proceed as follows:
The wire which is coloured BLUE must be connected to the terminal which is marked
with the letter N or coloured BLACK.
The wire which is coloured BROWN must be connected to the terminal which is marked
with the letter L or coloured RED.
Making sure that neither core is connected to the earth terminal of the three pin plug.
* This applies only to products distributed by YAMAHA - KEMBLE MUSIC (U.K.) LTD.

FEATURES
• The two-channel system offers completely independent chan¬
nel control — from the input all the way to the output. (Q2031B,
GQ2015A)
• The Q2031B/GQ1031C offers a narrow, 1/3-octave bandwidth
and 31-band control over the entire 20 Hz to 20 kHz range for
very precise equalization.
• The lU-size GQ2015A offers 15-band control on two inde¬
pendent channels.
• Equipped with an EQ switch that bypasses the equalizer sec¬
tion, a RANGE.switch that changes the equalization range
and a host of other features the equalizer presents itself as a
unit carefully designed from both functional and operational
perspectives.
• The Q2031B features a high pass filter that allows setting the
rolloff frequency using a slider, and the GQ1031C/GQ2015A
is equipped with an 80 Hz high pass filter.
• Equipped with transformerless balanced XLR-type and phone
jack input and output connectors.
• Suitable for PA and recording applications and a variety of
other uses.
• Can be mounted in a standard 19" rack.
CONTENTS
FRONT PANEL. 3
REAR PANEL.5
TYPICAL CONFIGURATIONS. 6
ACOUSTIC CONTROL . 7
SPECIFICATIONS..8
BLOCK DIAGRAM.9
DIMENSIONS. . . . 9

FRONT PANEL
Q2031B
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GQ1031C
GQ2015A

FRONT PANEL
O POWER switch
When this switch is pressed to turn the power on, the POWER
indicator LED above the switch will iight.
* To prevent click noise, the output is muted for approximately
two seconds after the power*is turned on.
O RANGE switch
Allows selection of the boost or cut range for equalization.
When this switch is off, the maximum range of +/-12 dB is
selected; when on, the +/-6 dB range is selected. Use this
switch to select the range suitable for each application. When
the switch is on, the LED indicator to its left lights to show
that the +/-6 dB range is in effect.
OHPF switch (Q2031B)
/SO^ switch (GQ1031C/GQ2015A)
Allows switching the high pass filter in or out of the audio
path. When the switch is on, the high pass filter is effective
and the indicator LED lights. The Q2031B provides 12 dB
per octave rolloff below the frequency set with the HPF con¬
trol 0, while on the GQ1031C/GQ2015Athe rolloff is 12 dB
per cotave below 80 Hz.
When the switch is off, the input signal goes directly to the
equalizer section, bypassing the HPF.
On the GQ2015A the /so^ switch turns the HPF on/off for
channels A and B simultaneously.
o EQ switch
This switch determines whether the signal is routed through
or bypasses the equalizer section. When the switch is off,
the equalizer is bypassed and the settings of the equalizer
controls O are ineffective, providing a flat frequency re¬
sponse. When the switch is on, its indicator lights and the
equalizer is switched into the audio path. The equalized sig¬
nal can be compared with the un-equalized signal simply by
alternately turning the EQ switch on and off.
0 LEVEL control
Allows precise control of the optimum input sensitivity. When
the control Is at the top of the scale, the input level remains
unchanged (+4 dB).
This control can be used to restore the output level when the
overall level has been changed during the equalization pro¬
cess. This, however, will also change the input level. Equal¬
ization methods which do not change the LEVEL control set¬
ting will yield a better signal-to-noise ratio and wider dynamic
range.
Example: The settings in Fig. A will provide a better result
than the settings in Fig. B.
• Boost/cut settings centered around the 0 dB point
lamH
m
Fig. A
• Boost/cut settings off the 0 dB point
Hg.B
@HPF control (Q2031B)
The HPF control sets the rolloff frequency for the built-in high
pass filter. The control allows continuous adjustment over
the range of 20 Hz to 200 Hz. Below the selected frequency
there will be a 12 dB per octave cut.
The filter is turned on/off using the HPF switch 0.
The HPF can be adjusted to eliminate low-range standing
waves, a resonance phenomenon that sometimes occurs in
small indoor environments, vocal "pops” and wind noise in
microphones and AC hum.
3