EQ-2231A Manual - Inter-M
Operation Manual
Dual 31-Band Graphic Equalizer
EQ-2231A
DUAL 31- BAND GRAPHIC EQUALIZER
Welcome
A personal welcome to you from the management and employees of Inter-M
All of the co-workers here at Inter-M are dedicated to providing excellent products with inherently good value,
and we are delighted you have purchased one of our products.
We sincerely trust this product will provide years of satisfactory service, but if anything is not to your complete
satisfaction, we will endeavor to make things right.
Welcome to Inter-M, and thank you for becoming part of our worldwide extended family!
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK.
DO NOT REMOVE COVER (OR BACK).
This symbol is intended to alert the user to the
presence of uninsulated “dangerous voltage” within
the products enclosure that may be of sufficient
magnitude to constitute a risk of electric shock to
persons.
This symbol is intended to alert the user to the
presence of important operation and maintenance
(servicing) instructions in the literature accompanying
the appliance.
NO USER-SERVICEABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
WARNING
To prevent fire or shock hazard, do not
expose the unit to rain or moisture.
Caution: To prevent electric shock do not use this (polarized) plug with
an extension cord, receptacle or other outlet unless the blades
can be fully inserted to prevent blade exposure.
Attentions: Pour prévenir les chocs électriques ne pas utiliser cette
fiche polarisée avec un prolongateur, une prise de courant
on une autre sortie de courant, sauf si les lames peuvent
étre insérées à fond sans en laisser aucune partie à
découvert.
*WARNING FOR YOUR PROTECTION PLEASE READ THE FOLLOWING-WATER AND MOISTURE: Unit should not be used near water(e.g.
near a bathtub, washbowl, kitchen sink, laundry tub, in a wet basement, or near a swimming pool, etc). Care should be taken so than objects do
not fall and liquids are not spilled into the enclosure through openings.
*Do not install this equipment in a confined space such as a book case or similar unit.
*This apparatus shall not be exposed to dripping or splashing and no objects filled with liquids, such vases, shall be placed on the apparatus.
*This apparatus shall be connected to a mains socket outlet with a protective earthing connection.
*It has heed to be easy to disconnect the device. To disconnect the device from power, separate AC input cable from inlet or unplug the AC Cord.
*The socket-outlet shall be installed near the equipment and shall be easily accessible.
CAUTION
*These servicing instructions are for use by qualified service personnel only. To reduce the risk of electric shock, do not perform any servicing
other than that contained in the operating instructions unless you are qualified to do so.
NOTE
*This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment
generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful
interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will
be required to correct the interference at his own expense.
DUAL 31- BAND GRAPHIC EQUALIZER
Contents
Unpacking .......................................................................................................................................2
Installation
Environment....................................................................................................................................2
Important Safety Instructions.............................................................................................................2
Short Form Instructions.....................................................................................................................3
Features............................................................................................................................................4
Accessories.....................................................................................................................................4
Front Panel ......................................................................................................................................5
Rear Panel .......................................................................................................................................7
Applications ....................................................................................................................................8
Operation ........................................................................................................................................9
Treating Feedback ...........................................................................................................................9
System Tuning...............................................................................................................................10
Troubleshooting ............................................................................................................................11
Assistance.....................................................................................................................................11
Block Diagram ..............................................................................................................................12
Specifications ................................................................................................................................13
Service
Procedures....................................................................................................................................15
Schematic .....................................................................................................................................15
Parts List .......................................................................................................................................15
Variations and Options ...............................................................................................................15
Warranty .......................................................................................................................................15
EQ-2231A
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DUAL 31- BAND GRAPHIC EQUALIZER
Unpacking
Although your EQ-2231A is neither complicated nor difficult to operate, we recommend you take a few minutes
to read this brief manual and familiarize yourself with the important information regarding product features,
setup and operation.
As with most electronic devices, we strongly recommend you to retain the original packaging. In the unlikely
event the product must be returned for servicing, the original packaging (or reasonable equivalent) is required.
Installation
Environment
Never place this product in an environment which could alter its performance or reduce its service life. Such
environments usually include high levels of heat, dust, moisture, and vibration.
IMPORTANT SAFETY INSTRUCTIONS
1.
2.
3.
4.
5.
6.
7.
8.
Read these instructions.
Keep these instructions.
Heed all warnings.
Follow all instructions.
Do not use this apparatus near water.
Clean only with dry cloth.
Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including
amplifiers) that produce heat.
9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades
with one wider than the other. A grounding type plug has two blades and a third grounding prong. The wide
blade or the third prong are provided for your safety. If the provided plug does not fit into your outlet, consult
an electrician for replacement of the obsolete outlet.
10. Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and
the point where they exit from the apparatus.
11. Only use attachments/accessories specified by the manufacturer.
12. Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus.
When a cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.
13. Unplug this apparatus during lightning storms or when unused for long periods of time.
14. Refer all servicing to qualified service personnel. Servicing is required when the
apparatus has been damaged in any way, such as power-supply cord or plug is
damaged, liquid has been spilled or objects have fallen into the apparatus, the
apparatus has been exposed to rain or moisture, does not operate normally, or has
been dropped.
S3125A
S3125A
2
EQ-2231A
DUAL 31- BAND GRAPHIC EQUALIZER
Short Form Instructions
1. Prior to connecting the AC or DC power, adjust the LEVEL slider control to the fully attenuated position (all
the way down).
2. All other sliders should be set to the “0” or center position.
3. The BYPASS switch should be in the OFF position.
4. Connect an appropriate line level input signal to either the balanced XLR or the balanced Euroblock
connector marked INPUTS.
5. Connect the OUTPUTS using either the balanced XLR or the balanced Euroblock connector to an
appropriate device.
6. With the power switch in the OFF position, plug in the supplied Universal AC power cord to the product
and an appropriate AC source.
7. Depress the power switch to the ON position. The power indicator will illuminate.
8. The product is ready for operation. Slowly increase the LEVEL slider to the desired operating level without
exceeding “0”, then make other adjustments as necessary.
9. Operate the product and the system in a manner which DOES NOT illuminate the PEAK warning indicator.
EQ-2231A
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DUAL 31- BAND GRAPHIC EQUALIZER
Features
- Dual channel, 31 band graphic equalizer.
- Constant Q (Constant Bandwidth) filter design.
- Long throw (45mm) slider controls.
- Balanced XLR and balanced Euroblock input and output connectors.
- Selectable adjustment range of ±6dB or ±12dB.
- Signal Bypass switch allows for a quick assessment of the effect of the equalizer’s settings.
- Peak warning indicator (active 6dB below peak).
- Selectable, Cut Only or Boost/Cut, operation.
- Selectable 80Hz high pass filter to reduce frequency response below 80Hz.
- Rack Ears for permanent installation in a standard 19” (rack mount width) enclosure.
- Detachable AC power cord.
- DC 24V power input.
Accessories
One detachable AC power cord and EURO BLOCKS are provided for use with this product.
4
EQ-2231A
DUAL 31- BAND GRAPHIC EQUALIZER
Front Panel
1
2
43 5
6
7
9
8
1. EQ BOOST / CUT CONTROL
These 45mm sliders control the amount of boost or cut applied to the indicated center frequency.
2. INPUT GAIN CONTROL
The position of the Input Gain slider determines the overall signal to the circuitry. The “0” position of each slider
indicates the position where no cut or boost occurs. This position (also known as unity gain) is the optimum
position.
3. PEAK WARNING INDICATOR
This LED illuminates red whenever the corresponding input signal is within 6dB of clipping. During normal
operation, the Peak Warning Indicator will remain off or only rarely illuminate.
4. RANGE SWITCH
The position of this switch determines if the slider controls operate over a ±6dB or a ±12dB range in the
boost/cut mode. In the CUT ONLY mode, the position of this switch changes the adjustments from -12dB to 24dB. In most cases, the ±6dB (-12dB in cut only) range is sufficient. Excessive adjustments may indicate a
problem elsewhere in the system that requires attention. The RANGE switch will illuminate when engaged,
effectively doubling the normal range of the slider controls.
5. CUT ONLY SWITCH
The position of this switch determines whether the corresponding slide controls perform a boost/cut or cut
only function. The switch will illuminate when the switch is in the CUT ONLY mode. In this mode, the “0”
position of the sliders is at the top of the range and any adjustment of the sliders will only attenuate the level
as indicated by the red CUT ONLY graphics. Usually -12dB of attenuation is sufficient. However the RANGE
switch can be employed to provide up to -24dB of attenuation if more than -12dB is needed.
EQ-2231A
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DUAL 31- BAND GRAPHIC EQUALIZER
6. HIGH PASS FILTER
The position of this switch determines if the 80Hz High Pass Filter is applied to the signal. The switch will illuminate
when the High Pass Filter is engaged. This feature is effective at removing rumble or other low frequency
information (below 80Hz) which may be undesirable.
7. BYPASS SWITCH
The position of this switch determines whether the product operates normally or allows the signal to bypass
all equalization settings and pass through unaffected. The switch will illuminate when it is in the BYPASS
mode. In the event of a loss of power, the product will default to BYPASS mode allowing the signal to pass.
8. POWER SWITCH
The position of this switch determines whether the power is ON or OFF. In the OFF position, the input(s) are
hard bypassed to the output(s) to allow the signal to pass through unaffected as it does in BYPASS.
9. POWER INDICATOR
Display the power ON/OFF.
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EQ-2231A
DUAL 31- BAND GRAPHIC EQUALIZER
Rear Panel
1
2
3
4
7
5
6
1. AC CONNECTOR AND FUSE HOLDER
Connect the supplied standard AC input cable to this input. The fuse holder below the input contains the AC
overload protection fuse. If the fuse has blown out, replace it with a fuse of the same type and rating. If the
fuse continues to blow, refer servicing to a qualified service technician.
2. DC INPUT TERMINAL
This terminal is provided for the connection of 24V DC power source. Connect a 24V DC battery source to
this terminal.
3. BALANCED XLR INPUT CONNECTORS
One balanced 3-pin female XLR input connector is provided for channel. This connector is wired in Parallel
to the corresponding balanced Euroblock output connector.
4. BALANCED EUROBLOCK INPUT CONNECTORS
One balanced male Euroblock input connector is provided for channel. This connector is wired in Parallel to
the corresponding balanced XLR input connector.
5. BALANCED XLR OUTPUT CONNECTORS
One balanced 3-pin male XLR output connector is provided for channel. This connector is wired in Parallel to
the corresponding balanced Euroblock output connector.
6. BALANCED EUROBLOCK OUTPUT CONNECTORS
One balanced male Euroblock output connector is provided for channel. This connector is wired in Parallel
to the corresponding balanced XLR output connector.
7. GROUND LIFT SWITCH
This switch provides connection or disconnection of the equalizer ground to AC “earth” ground to prevent
noise from ground loops. Under most circumstances, this switch should be set to FRAME position.
EQ-2231A
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DUAL 31- BAND GRAPHIC EQUALIZER
Applications
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EQ-2231A
DUAL 31- BAND GRAPHIC EQUALIZER
Operation
Correctly operating an equalizer is easier said than done. The explanation provided will direct the user on how
to make adjustments but cannot explain how to get the system to sound good, since that will come from
experience and patience.
It must first be determined how the Equalizer will be used in this system. Its primary task may be to treat
feedback, improve tonal quality, or both. Each task is explained below. If the plan is to use it for both, begin by
treating feedback first, then improve tonality second.
Treating Feedback
1. Begin with the all sliders set to the “0” position.
2. Determine the two or three frequencies that are most prone to feedback. This is best achieved through the use
of an audio frequency (or audio spectrum) analyzer but one is not required. Go directly to step #3 if you are
able to determine the frequencies of interest.
a. Treating Feedback (without the use of an analyzer)
As mentioned earlier, an analyzer is the best way for most people to determine which frequencies need
lowering. Two other methods exist but care must be taken to prevent feedback from occurring at levels
which could be damaging.
I The Boost-To-Find method is performed while the system is near feeding back. Slowly and carefully
increase one slider at a time to see how close it is to causing feedback then return it to the “0” position.
Do this one time for each slider making note of the two or three most prone to feeding back, these are
the frequencies of interest.
II The Cut-To-Find method is performed while the system is already feeding back or ringing (ringing is an
early stage of feedback). Feedback can cause damage to the system. Much care should be taken to insure
that feedback is not occurring at such levels as to cause damage. The procedure requires the lowering of
one slider at a time in an attempt to see if it’s the correct slider to affect the problem frequency. Only one
slider (out of many) will be the correct one. Assuming that the first one tried is incorrect, return it to the “0”
position and quickly try another. Repeat as necessary to locate the frequency.
3. Locate the slider that controls the feedback frequency and slowly lower the slider until the feedback stops. Be
sure not to lower the level more than the minimum amount required to stop the feedback. This will need to be
repeated as necessary to treat the worst frequencies. Usually it is not practical to treat more than two or three
frequencies as doing so will have a negative effect on tonality.
4. When finished, all but a few of the sliders will be at the “0” position. The few that were used to treat
feedback will be at approximately the -2dB or -3dB position.
5. Document your settings using the “Notes” page at the back of this manual. This will be useful in the vent that
the settings are inadvertently altered.
EQ-2231A
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DUAL 31- BAND GRAPHIC EQUALIZER
System Tuning
1. Begin with the all sliders set to the “0” position unless adjustments have been made to treat feedback.
2. Have a Plan. Identify what improvements the system needs and which of those are capable of being
addressed through equalization. System design, not equalization, determines the general parameters of
system performance. Do not attempt to counteract design shortfalls with an equalizer. An equalizer is the
perfect tool for making frequency specific adjustments which improve overall system performance.
3. Make the necessary adjustments remembering two important items.
a. Proper equalization is achieved with minimal equalization.
b. Better to cut than to boost. Cut excessive frequencies rather than boost weak frequencies.
4. Document your settings.
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EQ-2231A
DUAL 31- BAND GRAPHIC EQUALIZER
Troubleshooting
Assistance
This section assumes that the product functions properly and that one or more product features or functions have
been engaged, defeated, or not properly adjusted.
Begin troubleshooting by taking a moment to review the “Short Form Instructions” portion of this manual. It may
help to identify a feature that has been overlooked and related to the problem.
Symptom:
None of the frequency related slide controls have any affect.
Probable cause#1: The BYPASS switch is engaged, confirmed by illumination.
Probable cause#2: Loss of power, either the POWER switch is in the OFF position, or the product is not
connected to an AC or DC source. The POWER LED will illuminate when the POWER switch
is in the ON position and AC or DC power is available.
Symptom:
The frequency related slide controls below 80Hz have little or no affect.
Probable cause: The HPF has been engaged as confirmed by the illuminated corresponding LED.
Symptom:
Low output even with reasonable settings (approximately “0”)
Probable cause#1: The CUT ONLY switch is engaged as confirmed by the corresponding LED. With the CUT
ONLY switch engaged the red graphics are used and indicate that the 0 position (unity) has
moved from the middle to the top of the slider. The RANGE switch will magnify this effect if it
is engaged as confirmed by the corresponding LED.
Probable cause#2: Incompatible signal to or from other devices in the system.
Symptom:
Distorted sound and/or the PEAK LED is illuminated.
Probable cause#1: Too much boost because the RANGE switch is doubling the amount of boost.
Probable cause#2: Too much boost is occurring due the position of the sliders (above “0”).
Probable cause#3: Incorrect or overdriven input signal being received from another product. Be sure that this
product is only receiving one input signal per channel, XLR or euroblock, not both.
EQ-2231A
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DUAL 31- BAND GRAPHIC EQUALIZER
Block Diagram
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EQ-2231A
DUAL 31- BAND GRAPHIC EQUALIZER
Specifications
EQ-2231A
Input Sensitivity / Impedance
4dBu/>10kΩ, BAL (0dBu=0.775V)
Output Level / Impedance
4dBu/600Ω, BAL (0dBu=0.775V)
Total Harmonic Distortion
Less than 0.02%
(INPUT 1kHz, 4dBu, <80kHz FILTER, +20dBu)
Frequency Response
20Hz~20kHz (±1dB)
Signal to Noise Ratio
Better than -90dB(INPUT 1kHz, 4dBu, A-Weighting)
Equalizer Level
Center Frequency
±6dB
20Hz, 25Hz, 31.5Hz, 40Hz, 50Hz, 63Hz, 80Hz, 100Hz,
125Hz, 160Hz, 200Hz, 250Hz, 315Hz, 400Hz, 500Hz,
630Hz, 800Hz, 1kHz,1.25kHz, 1.6kHz, 2kHz, 2.5kHz,
3.15kHz, 4kHz, 5kHz, 6.3kHz, 8kHz, 10kHz, 12.5kHz,
16kHz, 20kHz
EQ GAIN
±6dB(RANGE SW OFF)
±12dB(RANGE SW ON)
High Pass Filter
80Hz (-18dB/oct)
Cut Only Mode
-12dB or -24dB±3dB
Operating Temperature
Power Source
Power Consumption
Weight (SET)
Dimensions (SET)
-10℃ ~ +40℃
AC 230V/240V, 50/60Hz
AC : 20W, DC : 24V / 0.7A
5kg
482(W)x88(H)x234(D)mm
* Specifications and design subject to change without notice.
EQ-2231A
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DUAL 31- BAND GRAPHIC EQUALIZER
※ DIMENSIONS
440.5
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EQ-2231A
DUAL 31- BAND GRAPHIC EQUALIZER
Service
Procedures
Take steps to insure the problem is not related to operator error or other products within the system. Information
provided in the troubleshooting portion of this manual may help with this process. Once it is certain that the
problem is related to the product contact your warranty provider as described in the warranty section of this
manual.
Schematic
A Schematic is available by contacting your warranty provider.
Parts List
A Parts List is available by contacting your warranty provider.
Variations and Options
Variations
Products supplied through legitimate sources are compatible with local AC power requirements.
Options
No optional items are available for this product.
Warranty
Warranty terms and conditions vary by country and may not be the same for all products. Terms and conditions
of warranty for a given product may be determined first by locating the appropriate country which the product
was purchased in, then by locating the product type.
To obtain specific warranty information and available service locations contact Inter-M directly or the authorized
Inter-M Distributor for your specific country or region.
EQ-2231A
15
NOTE
Inter-M, Ltd. (Korea) began operations in 1983.
Since then, Inter-M has grown to become one of the largest manufacturers
of professional audio and commercial sound electronics equipment in the world.
Inter-M has gained worldwide recognition for its own branded products,
as well as private label manufacturing of electronics sold under other names (OEM).
The company is no longer just a Korean company, but rather a global company
that is truly international in scope, with factories and offices in Korea and China,
and sales and marketing operations located in Japan, Europe, and the U.S.A.
With more than 850 employees around the globe,
Inter-M is well-poised for further growth and expansion.
Inter-M Americas, INC.
13875 Artesia Blvd. Cerritos, CA 90703 USA
TEL : +1-562-921-0313, FAX : +1-562-921-0370
Home Page : http://www.inter-m.net, E-mail : info@inter-m.net
Inter-M Corporation
Seoul OFFICE:653-5 BANGHAK-DONG, DOBONG-KU, SEOUL, KOREA
TEL : +82-2-2289-8140~8, FAX : +82-2-2289-8149
Home Page : http://www.inter-m.com, E-mail : overseas@inter-m.com
MADE IN KOREA
July 2012 131168
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