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Graphic Equalizers
CEQ215 170.923
CEQ231 170.926
User Manual
Features:
Switchable Bypass per channel
Switchable Low Cut filter per channel
Independent Gain controls
±12dB adjustment per band
Balanced or unbalanced signal path
LED VU display per channel
www.citronic.com
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Introduction:
Thank you for choosing a Citronic equalizer unit. This product has been designed to deliver professional tone-shaping facilities
with reliable and accurate function. In order to achieve the best results from this equipment and avoid damage through misuse,
please read and follow these instructions and retain for future reference.
Warning:
To prevent the risk of fire or electric shock, do not expose any part of the unit to rain or moisture.
If liquids are spilled on the surface, stop using immediately, allow unit to dry out and have checked by qualified personnel before
further use.
Avoid impact, extreme pressure or heavy vibration to the unit.
There are no user serviceable parts inside the equalizer– refer all servicing to qualified service personnel.
Safety
Check that the supplied mains lead is in good condition and the supply voltage is correct.
Ensure signal leads are of good condition and connected to appropriate inputs/outputs
Do not allow any foreign particles to enter the console through slider or connector apertures
Placement
Keep out of direct sunlight and away from heat sources.
Keep away from damp or dusty environments.
When rack-mounting, avoid placing heavy units above the unit and ensure all connectors are accessible
Cleaning
Use a soft cloth with a neutral detergent to clean the casing as required
Use a soft brush to clear debris from the control surface
Do not use strong solvents for cleaning the unit.
Front Panel
1. Independent GAIN controls
2. LOW CUT filter switches and indicators
3. IN/OUT bypass switches and indicators
4. LED VU indicators
5. Frequency sliders
6. Power button
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Rear Panel
What is Equalization?
Equalization (or EQ) is so called because its primary function is to accurately “equalize” or balance the frequency
profile of a signal for a given application or environment. This is especially noticeable in large rooms, which can
emphasise “boominess” in the low frequencies or rooms with soft furnishings, which can absorb a lot of the high
frequencies. An equalizer can be set to reduce “boomy” low frequencies or replace lost high frequencies.
At best, human ears can detect sound from 20Hz to 20000Hz (or 20Hz – 20kHz). All natural (and some unnatural)
sounds have many harmonics and overtones across the listening spectrum, giving them varying tonal
characteristics. We often refer to the lowest frequencies as “Bass” and the highest frequencies as “Treble” but this
only describes 2 regions of tone, whereas the listening spectrum could be divided into as many sections as desired
in order to give more accurate measurement and manipulation of the sound characteristics.
EQ can also be used as a tool to push a signal forward in a mix or set it further back into the mix by boosting or
cutting key mid frequencies, reducing feedback by cutting frequencies which are prone to resonance and boosting
specific frequencies to lift certain instruments in a piece of music.
Connection
The unit can be used in 2 configurations…
1. As 2 independent mono graphic equalizers – e.g. for 2 separate microphones on channel inserts
2. As a stereo left & right EQ – e.g. as a main L+R EQ on master inserts or between the mixer and amplifier.
Before connecting to an amplifier or other equipment, turn down all volume controls to avoid loud noises which may
cause damage to other equipment. Always switch amplifier power on last in line with volume levels down. Use good
quality 6.3mm jack or XLR signal leads to connect the equalizer to allied equipment. The unit can be used as 2
independent mono equalizers (e.g. for 2 microphone channels, requiring specific EQ profiles). Connect mains
power via the IEC (ensuring lead is in good condition and the voltage selector is same as the supply voltage) and
switch the POWER on.
7. IEC mains inlet
8. Mains voltage selector
9. Output 6.3mm jack
10. Outputs - XLRM
11. Inputs - XLRF
12. Inputs - 6.3mm jack
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Operation
Begin with all frequency sliders and the GAIN controls in the centre position (no boost or cut) at 0dB.
Switch the “IN/OUT” button to IN and the respective LED will light.
Adjust each frequency in turn to acquire the best response and reduce any problem frequencies.
Bear in mind that many loudspeakers cannot reproduce frequencies down as far as 20Hz and that the energy from
the amplifier at these low frequencies is wasted as heat in the speaker coil. Therefore, the “LOW CUT” may be
preferred to be on in sound reinforcement scenarios.
Also, with live PA situations, the crossover point between subs and mid-top cabs can generate phase problems
which may be alleviated by reducing frequencies around this point.
Extremely high frequencies are often not feasible for live sound systems, due to the limitations of microphones and
loudspeakers (and most people’s ears) and 20kHz may be reduced to save wasted amplifier energy at these high
frequencies.
For whichever particular application, experimentation and practice will eventually give the best results from your
equalizer.
SPECIFICATIONS
Power supply
115/230Vac 50/60Hz - selectable (IEC)
Frequency response
20Hz - 20kHz
Input impedance : Balanced
40kohms
Input impedance : Unbalanced
20kohms
Output impedance : Bal/Unbal
330ohms
Channel separation
>50dB
Signal to noise ratio
>102dB
THD
0.01%
Dimensions
44 x 482 x 138mm
Weight
2.0kg
Power supply
115/230Vac 50/60Hz - selectable (IEC)
Frequency response
20Hz - 20kHz
Input impedance : Balanced
40kohms
TROUBLESHOOTING
No function and Power switch LED is not lit
Ensure mains voltage is correct and connected properly
Ensure front panel power switch and mains outlet switch are on
Power is on but no audio output
Check XLR and/or jack leads are OK and connected properly
Check that GAIN control and sliders are not set to -12dB
Check that inputs and outputs are connected the correct way around
Distorted output
If overall frequency settings are above zero on average, reduce the Gain
Reduce frequency sliders with very high settings to check which is distorting
Output is very low level
If output from mixer is XLR, connect via XLR to equalizer
If input to amplifier is XLR, connect via XLR from equalizer
If output from mixer is jack, connect via jack to equalizer
If input to amplifier is jack, connect via jack from equalizer
Increase Gain control(s) to compensate
Note: for further troubleshooting, refer equipment to qualified service personnel for testing
© Citronic 2011
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