EQ-2131/2231/2215
B370031OC03OC03
0210
Graphic Equalizer
Contents
Contents
Welcome
Warning.........................................................................................................................................1
Unpacking......................................................................................................................................2
Short Form Instructions.....................................................................................................................2
Installation
Environment....................................................................................................................................3
Important Safety Instructions.............................................................................................................3
Description.......................................................................................................................................4
Features............................................................................................................................................4
Accessories.....................................................................................................................................4
Front Panel ......................................................................................................................................5
Rear Panel .......................................................................................................................................7
Applications
Rack System Installation (EQ-2131) MONO......................................................................................9
Rack System Installation (EQ-2231/2215) DUAL CHANNEL or STEREO ...........................................10
Music Stage Installation (EQ-2131) MONO ....................................................................................11
Music Stage Installation (EQ-2231/2215) STEREO 3-WAY..............................................................12
Connections...................................................................................................................................13
Operation
Treating Feedback.........................................................................................................................15
System Tuning...............................................................................................................................16
Troubleshooting
Assistance.....................................................................................................................................17
Block Diagrams
EQ-2131......................................................................................................................................18
EQ-2231......................................................................................................................................19
EQ-2215......................................................................................................................................20
Specifications ................................................................................................................................21
Service
Procedures....................................................................................................................................22
Schematic.....................................................................................................................................22
Parts List .......................................................................................................................................22
Variations and Options ...............................................................................................................22
Warranty .......................................................................................................................................22
GRAPHIC EQUALIZER
Welcome
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!
This symbol is intended to alert the user to the
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK.
DO NOT REMOVE COVER (OR BACK).
NO USER-SERVICEABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
Caution: To prevent electric shock do not use this (polarized) plug with
Attentions: Pour prévenir les chocs électriques ne pas utiliser cette
WARNING
To prevent fire or shock hazard, do not
expose the unit to rain or moisture.
*Do not install this equipment in a confined space such as a book case or similar unit.
*The apparatus shall not be exposed to dripping or splashing and no objects filled with liquids, such vases, shall be placed on the apparatus.
*Worded: “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.”
presence of uninsulated “dangerous voltage” within
the product’s enclosure that may be of suf-ficient
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 mainte-nance
(servicing) instructions in the literature accompanying
the appliance.
an extension cord, receptacle or other outlet unless the blades
can be fully inserted to prevent blade expo-sure.
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.
EQ-2131/2231/2215
1
GRAPHIC EQUALIZER
Unpacking
Please take a few minutes to read this manual to familiarize yourself with important information regarding
installation, product features, and operation.
As with most electronic devices, ORIGINAL PACKAGING (OR EQUAL) IS REQUIRED in the unlikely event that
the product needs to be returned for servicing.
Short Form Instructions
1. Prior to connecting the AC 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 1/4” TRS (TipRing-Sleeve) connector marked INPUTS.
5. Connect the OUTPUTS using either the balanced XLR or the balanced 1/4” TRS 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. An LED within the power switch 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-2131/2231/2215
2
GRAPHIC EQUALIZER
S3125A
Installation
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. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with dry cloth.
7. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
8. 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
EQ-2131/2231/2215
3
GRAPHIC EQUALIZER
Description
Description
- EQ-2131
This product is a 2U rack space, single channel, 31 band, graphic equalizer.
- EQ-2231
This product is a 2U rack space, dual channel, 31 band, graphic equalizer.
- EQ-2215
This product is a 2U rack space, dual channel, 15 band, graphic equalizer.
Features
Features
- Constant Q (Constant Bandwidth) filter design
- Long throw (45mm) slider controls
- Balanced XLR and balanced 1/4” TRS 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.
- Illuminated Power Switch
- Rack Ears for permanent installation in a standard 19” (rack mount width) enclosure.
- Detachable AC power cord
Accessories
One detachable AC power cord is provided for use with this product.
EQ-2131/2231/2215
4
Front Panel
12345
67 8
32145
67 8
3145
67 8
2
EQ-2131
EQ-2231
EQ-2215
Front Panel
GRAPHIC EQUALIZER
EQ-2131/2231/2215
5
GRAPHIC EQUALIZER
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. A single Peak Warning
Indicator is provided for the EQ-2131 and two are provided on the EQ-2231 and EQ-2215, one for each of
the two channels (Channel A and Channel B).
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. A single RANGE switch is provided for the EQ-2131 and two are provided on
the EQ-2231 and EQ-2215, one for each of the two channels (Channel A and Channel B). 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. A single CUT
ONLY switch is provided for the EQ-2131 and two are provided on the EQ-2231 and EQ-2215, one for
each of the two channels (Channel A and Channel B).
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. A single HPF switch is provided on the EQ-2131 and two are provided on
the EQ-2231 and EQ-2215, one for each of the two channels (Channel A and Channel B). 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. A single BYPASS switch is provided on the EQ-2131 and two are provided on the EQ-2231 and EQ2215, one for each of the two channels (Channel A and Channel B). 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. The power-on status is indicated by
the LED inside the switch. 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.
EQ-2131/2231/2215
6
Rear Panel
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
INPUTS
BALANCED
10KΩ, 4dBu
UNITY GAIN
BALANCED
10KΩ, 4dBu
BALANCED
10KΩ, 4dBu
UNITY GAIN
BALANCED
10KΩ, 4dBu
CHANNEL ACHANNEL B CHANNEL ACHANNEL B
OUTPUTS
OUTPUTS
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
INPUTS
BALANCED
10KΩ, 4dBu
UNITY GAIN
BALANCED
10KΩ, 4dBu
BALANCED
10KΩ, 4dBu
UNITY GAIN
BALANCED
10KΩ, 4dBu
CHANNEL ACHANNEL B CHANNEL ACHANNEL B
OUTPUTS INPUTS
BALANCED
10KΩ, 4dBu
UNITY GAIN
BALANCED
10KΩ, 4dBu
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
34
12
354
12
12
5
354
EQ-2131
EQ-2231
EQ-2215
Rear Panel
GRAPHIC EQUALIZER
EQ-2131/2231/2215
7
GRAPHIC EQUALIZER
1. BALANCED XLR INPUT CONNECTORS
One balanced 3-pin female XLR input connector is provided for each channel. This connector is wired in
Parallel to the corresponding balanced 1/4” TRS input connector.
2. BALANCED 1/4” TRS INPUT CONNECTORS
One balanced female 1/4” TRS input connector is provided for each channel. This connector is wired in
Parallel to the corresponding balanced XLR input connector.
3. BALANCED XLR OUTPUT CONNECTORS
One balanced 3-pin male XLR output connector is provided for each channel. This connector is wired in
Parallel to the corresponding balanced 1/4” TRS output connector.
4. BALANCED 1/4” TRS OUTPUT CONNECTORS
One balanced female 1/4” TRS output connector is provided for each channel. This connector is wired in
Parallel to the corresponding balanced XLR output connector.
5. AC INPUT
Connect this product to an appropriate AC power source using the supplied Universal AC Power Cord.
EQ-2131/2231/2215
8
Applications
Applications
RACK SYSTEM INSTALLATION (EQ-2131)MONO
GRAPHIC EQUALIZER
AC
Input
AC
Input
AC
Input
0.4A/250V
FUSE
INSERT INSERT
OUTPUT OUTPUT
CH 2
CH 12 CH 10CH 11 CH 9
CH 1
DC INPUT
24V
CH1
REC OUTPUT PRIORITY INPUT
LINE
LINE LINE LINE LINE LINE LINE LINE
MIC MIC MIC MIC MIC MIC MIC MIC
CH 5 CH 4 CH 3 CH 2 CH 1CH 8 CH 7 CH 6
Pre-Amplifier (PP-9214)
MUTE
ON
OFF
STEREO DOUBLE CASSETTE DECK
9335AD
PC
L dB
8
+20-3-6-11
R LEVEL
COUNTER
AUTO REVERSE
PLAY LOGIC DECK
DECK A
AB
RELAYBLANKMEMOREC DUBING
OPEN OPEN
SKIP/B REC PAUSE
R/PLAYMEMO
AMS AMS AMS AMS
AUTO REVERSE
RESET
DUBBINGNOR HIGH
MODE
RECORDING PLAY LOGIC DECK
REC
MUTE
DECK BDECK A
Line Level Sources
b
REC LEVEL
MIN MAX
OUTPUT LEVEL
d
MIN MAX
POWER
DECK B
ON
OFF
PHONES
Microphones
OUTPUTS INPUTS
BALANCED 75Ω
, 60Hz
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED
10KΩ, 4dBu
UNITY GAIN
BALANCED
10KΩ, 4dBu
EQ-2131
OUTPUT
A
B
COM
38V(4)
54V(8)
70V(13.6)
BALANCED
INPUT
1V/10K
LINK
GROUND
LIFT
FRAMEFLOA T
DC INPUT
24V
Power Amplifier (PA-9336)
CH 1
FUSE : 12A / 250V
ON OFF
INPUT(ADJ)
HPF
12dB 0dB
SWED 1
(2000W)
SWED 2
(2000W)
SWED 3
(2000W)
UNSWITCHED
(RACK ONLY)
SWITCHED
DC OUT 24V
5A MAX
( )
( )
UNSWED
(700W)
(AMP ONLY)
SWITCHED DC OUT 24V
BATTERY
INPUT 24V
( )
S
N
( )
DC OUTPUT 24V,1AMAX
REMOTE
C-SW-H
AC INPUT
~
230V/50Hz,217VA
EMERGENCY
GND
( )
www.inter-m.com
AC FUSE
T2AL/250V
DC FUSE
T5A/250V
P.A Speakers
Power Distributor (PD-9359E)
EQ-2131/2231/2215
9
GRAPHIC EQUALIZER
RACK SYSTEM INSTALLATION (EQ-2231/2215) DUAL CHANNEL or STEREO
AC
Input
AC
Input
AC
Input
0.4A/250V
FUSE
OUTPUT
COM
38V(4 )
FUSE : 12A / 250V
INSERT INSERT
OUTPUT OUTPUT
CH 2
CH 12 CH 10CH 11 CH 9
CH 1
CH1CH2
DC INPUT
REC OUTPUT PRIORITY INPUT
LINE
LINE LINE LINE LINE LINE LINE
MIC
MIC MIC MIC MIC MIC MIC MIC
24V
CH 5 CH 4 CH 3 CH 2 CH 1CH 8 CH 7 CH 6
Pre-Amplifier (PP-9214)
MUTE
ON
OFF
STEREO DOUBLE CASSETTE DECK
9335AD
PC
L dB
8
+20-3-6-11
R LEVEL
COUNTER
AUTO REVERSE
RESET
AB
RELAYBLANKMEMOREC DUBING
DUBBINGNOR HIGH
OPEN OPEN
MODE
PLAY LOGIC DECK
REC
MUTE
SKIP/B REC PAUSE
R/PLAYMEMO
DECK A
AMS AMS AMS AMS
b
REC LEVEL
AUTO REVERSE
MIN MAX
OUTPUT LEVEL
d
MIN MAX
RECORDING PLAY LOGIC DECK
POWER
DECK B
ON
OFF
PHONES
DECK BDECK A
Line Level Sources
Microphones
BALANCED 75
4dBu UNITY GAIN
OUTPUTS
BALANCED 75
BALANCED 75
4dBu UNITY GAIN
Ω
Ω
4dBu UNITY GAIN
Ω
BALANCED 75
4dBu UNITY GAIN
CHANNELACHANNELB CHANNELACHANNELB
Ω
INPUTS
BALANCED
10KΩ, 4dBu
UNITY GAIN
BALANCED
10KΩ, 4dBu
UNITY GAIN
BALANCED
10KΩ, 4dBu
BALANCED
10KΩ, 4dBu
EQ-2231/2215
A
B
54V(8 )
70V(13.6 )
BALANCED
INPUT
LINK
1V/10K
INPUT(ADJ)
ON OFF
HPF
12dB 0dB
GROUND
LIFT
FRAMEFLOAT
DC INPUT
24V
Power Amplifier (PA-9336)
CH 1
OUTPUT
A
B
COM
38V(4 )
54V(8 )
70V(13.6 )
AC
Input
INPUT(ADJ)
HPF
ON OFF
12dB 0dB
FUSE : 12A / 250V
SWED 1
(2000W)
SWED 2
(2000W)
SWED 3
(2000W)
10
EQ-2131/2231/2215
BALANCED
INPUT
LINK
1V/10K
( )
( )
(RACK ONLY)
SWITCHED
DC OUT 24V
5A MAX
UNSWED
(700W)
GROUND
LIFT
FRAMEFLOAT
DC INPUT
24V
CH 2
GND
P. A Speakers
AC FUSE
T2AL/250V
DC FUSE
T5A/250V
(AMP ONLY)
SWITCHED DC OUT 24V
BATTERY
INPUT 24V
( )
S
N
Power Amplifier (PA-9336)
UNSWITCHED
REMOTE
DC OUTPUT 24V,1AMAX
C-SW-H
( )
( )
AC INPUT
~
230V/50Hz,217VA
www.inter-m.com
EMERGENCY
Power Distributor (PD-9359E)
OUTPUTS INPUTS
BALANCED
10KΩ, 4dBu
UNITY GAIN
BALANCED
10KΩ, 4dBu
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
PUSH PUSH
PUSH TO RESET
20A / 250V
OUTPUT
STEREO
(4Ω ~ 8Ω)
INPUT
BALANCED
0dBm
BALANCED
0dBm
BRIDGED
PARALLEL
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
•TIP=HOT
•RING=COLD
•SLEEVE=GND
TRS
BALANCED
XLR
BALANCED
•3=COLD
•2=HOT
•1=GND
BRIDGED
(8Ω~16Ω)
CH 1CH 2CH 1CH 2
PUSH PUSH
PUSH TO RESET
20A / 250V
OUTPUT
STEREO
(4Ω ~ 8Ω)
INPUT
BALANCED
0dBm
BALANCED
0dBm
BRIDGED
PARALLEL
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
•TIP=HOT
•RING=COLD
•SLEEVE=GND
TRS
BALANCED
XLR
BALANCED
•3=COLD
•2=HOT
•1=GND
BRIDGED
(8Ω~16Ω)
CH 1CH 2CH 1CH 2
PUSH PUSH
PUSH TO RESET
20A / 250V
OUTPUT
STEREO
(4Ω ~ 8Ω)
INPUT
BALANCED
0dBm
BALANCED
0dBm
BRIDGED
PARALLEL
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
•TIP=HOT
•RING=COLD
•SLEEVE=GND
TRS
BALANCED
XLR
BALANCED
•3=COLD
•2=HOT
•1=GND
BRIDGED
(8Ω~16Ω)
CH 1CH 2CH 1CH 2
LOW INPUTMONO SUBWOOFER
HIGH LOW INPUT 2
HIGH MID
HIGH LOW INPUT 1
STEREO
MONO
FUSE
0.2A / 250V
STEREO / MONO
GROUND
FLOATFRAME
M-500/700/1000
DIV-9123
Audio Mixer
HIGH
MID
LOW
SPEAKER
EQ-2131
MUSIC STAGE INSTALLATION (EQ-2131) MONO
GRAPHIC EQUALIZER
EQ-2131/2231/2215
11
GRAPHIC EQUALIZER
OUTPUTS
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
BALANCED 75Ω
4dBu UNITY GAIN
INPUTS
BALANCED
10KΩ, 4dBu
UNITY GAIN
BALANCED
10KΩ, 4dBu
BALANCED
10KΩ, 4dBu
UNITY GAIN
BALANCED
10KΩ, 4dBu
CHANNEL ACHANNEL B CHANNEL ACHANNEL B
PUSH PUSH
PUSH TO RESET
20A / 250V
OUTPUT
STEREO
(4Ω ~ 8Ω)
INPUT
BALANCED
0dBm
BALANCED
0dBm
BRIDGED
PARALLEL
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
•TIP=HOT
•RING=COLD
•SLEEVE=GND
TRS
BALANCED
XLR
BALANCED
•3=COLD
•2=HOT
•1=GND
BRIDGED
(8Ω~16Ω)
CH 1CH 2CH 1CH 2
PUSH PUSH
PUSH TO RESET
20A / 250V
OUTPUT
STEREO
(4Ω ~ 8Ω)
INPUT
BALANCED
0dBm
BALANCED
0dBm
BRIDGED
PARALLEL
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
•TIP=HOT
•RING=COLD
•SLEEVE=GND
TRS
BALANCED
XLR
BALANCED
•3=COLD
•2=HOT
•1=GND
BRIDGED
(8Ω~16Ω)
CH 1CH 2CH 1CH 2
PUSH PUSH
PUSH TO RESET
20A / 250V
OUTPUT
STEREO
(4Ω ~ 8Ω)
INPUT
BALANCED
0dBm
BALANCED
0dBm
BRIDGED
PARALLEL
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
(4Ω ~ 8Ω)
•TIP=HOT
•RING=COLD
•SLEEVE=GND
TRS
BALANCED
XLR
BALANCED
•3=COLD
•2=HOT
•1=GND
BRIDGED
(8Ω~16Ω)
CH 1CH 2CH 1CH 2
LOW INPUTMONO SUBWOOFER
HIGH LOW INPUT 2
HIGH MID
HIGH LOW INPUT 1
STEREO
MONO
FUSE
0.2A / 250V
STEREO / MONO
GROUND
FLOATFRAME
M-500/700/1000
DIV-9123
Audio Mixer
MONO
SUBWOOFER
CH2, HIGH
CH2, LOW
CH1, HIGH
CH1, LOW
EQ-2231/2215
MUSIC STAGE INSTALLATION (EQ-2231/2215) STEREO 3-WAY
12
EQ-2131/2231/2215
Connections
Ring
Ring
Tip
Tip
Sleeve
Sleeve
Send
Return
Screen
Hot (
positive)
Cold (
negative)
Screen
Left Signal
Right Signal
Ground
Signal
Ground
3 Pole (Stereo) Jack
2 Pole (Mono) Jack
Ring TipSleeve
TipSeeve
2
1
3
Balanced Input
Hot (positive)
Hot (positive)
Sleeve
Screen
Cold (negative)
Cold (negative)
Connections
Inter-M products are wired to reflect accepted wiring practices used throughout the world.
Balanced XLR connectors are wired as described:
Pin #1 Shield
Pin #2 Positive
Pine #3 Negative
Balanced 1/4" TRS connectors are wired as described:
Tip is Positive
Ring is Negative
Sleeve is Shield
GRAPHIC EQUALIZER
Insert Points
Amp/Line Input
Headphones
Unbalanced
Input/Output
AUX Send
EQ-2131/2231/2215
13
GRAPHIC EQUALIZER
Input
Connect an appropriate line level input signal to either the balanced XLR or the balanced 1/4” TRS connector
marked INPUTS. Common and standard rules of interconnect apply, including limiting the number of inputs to
one per channel. Knowledge of the input signal is required and should be Balanced Low Impedance 1KOhm
+4dBu.
Output
Connect the OUTPUTS using either the balanced XLR or the balanced 1/4” TRS connector to an appropriate
device. Common and standard rules of interconnect apply, including the ability to split output signals.
Knowledge of the input requirements of the receiving device is required and should be Balanced +4dBu and at
least 10kOhms.
14
EQ-2131/2231/2215
GRAPHIC EQUALIZER
Operation
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-2131/2231/2215
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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-2131/2231/2215
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 source. The POWER LED will illuminate when the POWER switch is in
the ON position and AC 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 1/4”, not both.
EQ-2131/2231/2215
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GRAPHIC EQUALIZER
Block Diagrams
Block Diagrams
EQ-2131
18
EQ-2131/2231/2215
EQ-2231
GRAPHIC EQUALIZER
EQ-2131/2231/2215
19
GRAPHIC EQUALIZER
EQ-2215
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EQ-2131/2231/2215
GRAPHIC EQUALIZER
Specifications
Specifications
- ELECTRICAL
Output Level / Impedance....................................................................................................0dB/600Ω, BAL
Input Sensitivity / Impedance................................................................................................0dB/600Ω, BAL
Total Harmonic Distortion .....................................................................................................Less than 0.01%
Frequency Response......................................................................................................20Hz~20kHz (±1dB)
Signal to Noise Ratio...........................................................................................................Better than 85dB
Equalizer Level ....................................................................................................................................±6dB
Equalizer Frequency
EQ-2131/2231............................................1/3 Octave ISO (International-Standard-Organization) centers
EQ-2215 ..............................................................................................................2/3 Octave ISO centers
High Pass Filter...................................................................................................................80Hz (18dB/oct)
Cut Only Mode.............................................................................................................-12dB or -24dB±3dB
- GENERAL
Power Source ............................................................................ 100–120VAC or 220V–240VAC; 50/60Hz
Power Consumption .................................................................................................. EQ-2131/2215: 15W
..........................................................................................................................................EQ-2231: 20W
Weight ........................................................................................................... EQ-2131/2215: 4.5kg/10lb
....................................................................................................................................EQ-2231: 5kg/11lb
Dimensions .................................................................... 482(W)x88(H)x280(D)mm / 19(W)x3.5(H)x11(D)in
......................................................................................................................0dB=1Vrms
(Supplied AC mains transformer depends on country requirements)
*Specifications and design subject to change without notice.
EQ-2131/2231/2215
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GRAPHIC EQUALIZER
Service
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 and Options
Variations
Variations of this product exist to reflect the variations in AC power requirements throughout the world. Product
supplied through local sources are compatible with local AC power requirements.
Options
No optional items are available for this product.
Warranty
Warranty
To obtain the specific warranty information for your product as well as the location of a service station, please
contact Inter-M Ltd. in Korea, Inter-M Americas, Inc. in the United States of America, or the local distributor or
dealer where you purchased this product.
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EQ-2131/2231/2215
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.
1 EAST BEACON LIGHT LANE CHESTER, PA USA 19013-4409
TEL : (610) 874-8870, FAX : (610) 874-8890
Home Page : http://www.inter-m.net, E-mail : service@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 : export@inter-m.com
PRINTED IN KOREA
October 2004 9007100110 B
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