
CEQ215 / CEQ231 
Graphic Equalizers 
Order ref: 170.923UK / 170.926UK 
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 

Caution: Please read this manual carefully before operating 
Damage caused by misuse is not covered by the warranty 
Introduction 
Thank you for choosing a Citronic equalizer unit. This product has been designed to deliver professional toneshaping 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.   
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Front Panel 
Independent GAIN controls 
LOW CUT filter switches and indicators 
IN/OUT bypass switches and indicators 
Independent GAIN controls 
LOW CUT filter switches and indicators 
IN/OUT bypass switches and indicators 
Rear Panel 
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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 amp. 
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. 
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. 
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Specifications 
115/230Vac 50/60Hz - selectable (IEC) 
Input impedance : Balanced 
Input impedance : Unbalanced 
Output impedance : Bal/Unbal 
115/230Vac 50/60Hz - selectable (IEC) 
Input impedance : Balanced 
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 
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 
Disposal: The “Crossed Wheelie Bin” symbol on the product means that the product is classed as Electrical or 
Electronic equipment and should not be disposed with other household or commercial waste at the end of its useful life. 
The goods must be disposed of according to your local council guidelines. 
Troubleshooting 
Note: for further troubleshooting, refer equipment to qualified service personnel for testing 
Errors and omissions excepted. 
Copyright© 2013. AVSL Group Ltd. 
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