Shure SCM410 User manual

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SCM410 SCM410E -- Four-Channel Micro-
phone Mixer
Safety Information
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. Allow sufficient distances for adequate ventilation and install in accor-
dance with the manufacturer’s instructions.
8. DO NOT install near any heat sources such as open flames, radiators, heat registers, stoves, or other appara-
tus (including amplifiers) that produce heat. Do not place any open flame sources on the product.
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 wider
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 a 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 dam-
aged 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.
15. DO NOT expose the apparatus to dripping and splashing. DO NOT put objects filled with liquids, such as vas-
es, on the apparatus.
16. The MAINS plug or an appliance coupler shall remain readily operable.

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17. The airborne noise of the Apparatus does not exceed 70dB (A).
18. Apparatus with CLASS I construction shall be connected to a MAINS socket outlet with a protective earthing
connection.
19. To reduce the risk of fire or electric shock, do not expose this apparatus to rain or moisture.
20. Do not attempt to modify this product. Doing so could result in personal injury and/or product failure.
21. Operate this product within its specified operating temperature range.

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This symbol indicates that dangerous voltage constituting a risk
of electric shock is present within this unit.
This symbol indicates that there are important operating and
maintenance instructions in the literature accompanying this unit.
WARNING: Voltages in this equipment are hazardous to life. No user-ser-
viceable parts inside. Refer all servicing to qualified service personnel. The
safety certifications do not apply when the operating voltage is changed
from the factory setting.
General Description
The Shure Model SCM410/E is a four-channel automatic microphone mix-
er for use in sound reinforcement, audio recording, and broadcast applica-
tions. The SCM410 dramatically improves audio quality in any application
where multiple microphones are required. Any low-impedance dynamic or
condenser microphone (including wireless) can be used with the SCM410.
Multiple SCM410 mixers can be linked to other SCM410 mixers, as well as
to Shure Models FP410, SCM810, and SCM800.
Each input channel has a two-band equalizer and three logic terminals.
The equalizer reduces unwanted low-frequency audio pickup and makes
different microphone types-lavaliers, boundary and handheldsound similar.
The logic terminals can be used to control external devices.
The SCM410 operates on 100-120 Vac power and the SCM410E operates
on 220-240 Vac power. Each mixer is supplied with a power cord, rack-
mounting hardware, and a link cable.
Features
•Fast, noise-free microphone selection, which automatically adjusts to changes in background noise
• Automatic gain adjustment as additional microphones are activated- NOMA (Number of Open Microphones At-
tenuated)
•Last Mic Lock-On circuit maintains ambient sound
•Fits in half-rack space
•Adjustable EQ for each channel
•Active balanced microphone-level XLR inputs and an active balanced Mic/Line level XLR output
•Unbalanced auxiliary-level phono output

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•Bi-color channel activation and clipping LEDs
•Peak-responding output limiter with LED indicator
•Peak-responding output level meter
Operating Principles
The operating concept behind the SCM410 Automatic Mixer is Shure's proprietary IntelliMix® circuitry. Intellimix
delivers seamless automatic mixing by combining three separate functions:
•Noise Adaptive Threshold. Distinguishes between constant background noise (such as air conditioning) and
changing sound (such as speech) for each input channel. It continuously adjusts the activation threshold so that
only speech levels louder than the background noise activate a channel.
•MaxBus. Controls the number of channels that may be activated for a single sound source. One talker activates
only one channel, even if multiple microphones “hear” that talker.
•Last Mic Lock-On. Keeps the most recently activated microphone open until another microphone is activated.
Without Last Mic Lock-On, a long pause in conversation would cause all microphones to turn off, which would
sound as if the audio signal had been lost. Last Mic Lock-On ensures that background ambience is always
present.
IntelliMix is a registered trademark of Shure Incorporated.
Front Panel
Microphone Channel Gain Controls 1 - 4
Allows adjustment of microphone gain.
Input LED 1 - 4
Lights green when channel is active; lights red at 6 dB below clipping level.
Low-Cut Filter 1 - 4
Provides adjustable low-frequency rolloff (high pass), reducing presence of undesirable low-frequency signals.
High-Frequency Shelving Filter 1 - 4
Provides level boost or cut in mid/high-frequency region for reduced sibilance from vocal microphones, or to com-
pensate for off-axis coloration in lavalier microphones.
Output Level Meter
Six-segment LED meter indicates peak output signal level in dBu (0 dBu = 0.775V). The red LED illuminates when
the output is 6 dB below clipping. The last LED indicates limiter action.
MASTER Level Control
1
2
3
4
5
6

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Controls overall output level.
POWER LED
Lights green when mixer is plugged into a power source.
POWER Switch
Turns the mixer on and off.
Note: Country dependant
Rear Panel
Power Connector
Unit is energized when the power cord is plugged into a 100-120 Vac (SCM410) or 220-240 Vac (SCM410E) pow-
er source. NOTE: There is no power On/Off switch on this mixer.
DIP Switch
The 4-position DIP switch provides additional functions. Refer to the “DIP Switch Functions”section.
Microphone Logic Connector
High density DB-15 male connector provides connection to GATE OUT, MUTE IN, and OVERRIDE IN logic termi-
nals on each channel. Refer to the “Advanced Functions” section.
Note: This is not a VGA monitor port.
AUX OUT Phono Connector
Feeds consumer-level audio equipment, such as a tape recorder, VCR, or video camera. Not affected by MIC/
LINE switch.
MIC/LINE XLR OUTPUT Connector
Can be set for microphone or line-level output via a DIP switch.
LINK IN/OUT Connector
Permits multiple SCM410/E, FP410, SCM810, SCM800, or AMS8100 mixers to be linked, creating additional in-
puts.
MIC LEVEL XLR INPUT Connectors
Active balanced microphone-level XLR inputs. For instructions on how to modify the level of these inputs, refer to
the “Internal Modifications” Addendum.
7
8
1
2
3
4
5
6
7

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DIP Switch Functions
The rear panel DIP switches, shown in Figure 1, provide the functions listed in the table below.
Last Mic Lock-On XLR Output Level Limiter 12V Phantom Pow-
er
Switch Number 1 2 3 4
Switch Up All mics off after
hold time
Mic Level ON ON
Switch Down ON* Line Level OFF* OFF*
* Factory setting
Last Mic Lock-On
Keeps the most recently activated microphone turned on until another microphone is activated. When defeated,
microphones turn off after their default hold time. XLR Output Level: Sets the level of the XLR output to line or mi-
crophone level. Make sure the output level matches the input level of the device connected to the SCM410.
Note: The output level does not affect the auxiliary output (AUX OUT) level.
Limiter
Activates the output limiter and sets it to a default threshold of +16 dBu (see Internal Modifications Addendum for
other threshold settings).
12V Phantom Power
When this switch is in the ON position, the SCM410 provides 12Vdc phantom power to each XLR microphone in-
put. This function is particularly useful when using condenser microphones, since most condenser microphones
require phantom power.
Note: Phantom power does not affect the operation of balanced dynamic microphones. They can be connected to
the SCM410 in combination with condenser microphones that use phantom power. For instructions on how to dis-
able phantom power by channel, refer to the Internal Modifications Addendum.
Installation
Rack Mounting
The SCM410 is supplied with hardware for mounting one or two units to a 19-inch audio equipment rack. The
hardware can also be used to rack mount other Shure products, including the SCM268, SCM262, DFR11EQ, and
the DP11EQ.

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Single Mixer (Half Rack) Installation
1. Attach the short and long rack-mount brackets to the SCM410/E with eight (8) of the supplied bracket screws.
INSTALLING HALF RACK MOUNTING BRACKETS
2. Place the mixer in an equipment rack and secure it with the supplied rack-mount screws and plastic washers.
RACK MOUNTING A SINGLE SCM410/E MIXER
Dual Mixer (Full Rack) Installation
1. Place the two mixers side-by-side and connect them with two (2) straddle brackets. The brackets should strad-
dle the recessed edges on the top and bottom of each mixer.
INSTALLING STRADDLE BRACKETS
2. Fasten the straddle brackets using eight (8) bracket screws.
3. Attach the short rack-mount brackets to the outsides of the combined mixers with eight (8) of the bracket
screws.
INSTALLING FULL RACK MOUNTING BRACKETS
4. Place the mixer in an equipment rack, using the supplied rack-mount screws and plastic washers.

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RACK MOUNTING DUAL SCM410/E MIXERS
Table-Top Mounting
Adhere the four (4) supplied rubber feet to the bottom of the mixer at each corner. This will keep it from sliding and
protect the table surface.
ATTACHING RUBBER FEET FOR TABLE-TOP MOUNTING
Fixed Mounting
Top Mount
1. Fasten the straddle brackets to the recessed edges of the chassis, using four (4) bracket screws.
INSTALLING STRADDLE BRACKETS FOR TOP MOUNTING
2. Fasten the straddle brackets to the top of the mounting surface, using the four (4) supplied wood screws.

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SECURING MIXER TO TOP MOUNTING SURFACE
Hanging Mount
Note: The hardware provided is for attachment to wood. Other surfaces require the use of appropriate hardware
rated for 15 lbs. or more.
1. Fasten the straddle brackets to the top of the mixer.
INSTALLING STRADDLE BRACKETS FOR HANG MOUNTING
2. Fasten the straddle brackets to the bottom of the mounting surface, using the four (4) supplied wood screws.
SECURING MIXER TO BOTTOM MOUNTING SURFACE
SCM410 Connections
1. Connect microphone signal sources to the Channel Input connectors. Use conventional 2-conductor shielded
audio cables.
2. If any condenser microphones are connected, set the +12V phantom power DIP switch to ON.
3. Connect the SCM410 Mic/Line Level Output to the input of mixers, EQs, amplifiers, or recorders.
4. Connect the power cord to 100-120 Vac (SCM410) or 220-240 Vac (SCM410E)

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Linking Multiple Mixers
If more than four inputs are needed, multiple Shure SCM410, FP410, or SCM810 mixers can be linked by connect-
ing the LINK OUT of the first mixer to the LINK IN of the next mixer, and so on. See Figure 2. Leave the LINK IN
jack of the first mixer and the LINK OUT jack of the last mixer unconnected.
When properly linked, the mixers will operate as a system. Automatic mixing functions will be shared by all units.
All input signals appear at all linked mixer outputs. Each mixer's Master level control only controls its own output.
However, actual off-attenuation will increase as more mixers are linked. This reduces excessive noise and rever-
beration contributed by the increased number of microphones.
Important: When using logic terminals on linked mixers, connect the LOGIC GROUND terminals of each
unit together.
Note: SCM410 link connections are unbalanced. To minimize hum and noise, avoid using longer link cables. Use
high quality, shielded cable, and keep them away from sources of magnetic or electrical noise, such as power
transformers or light dimmers. To minimize ground currents, make sure linked mixers are connected to the same
AC power mains.
FIGURE 1: LINKED SCM410 AND SCM810 MIXERS

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Basic Mixer Operation
1. Adjust each channel level so that its Overload LED flickers only during very loud speech or noise.
2. Adjust the Low-Cut and High-Frequency controls adjacent to each Input Gain control so that the microphones
sound similar.
3. Adjust the Master level control for the required output level, as indicated by the output peak meter. The
SCM410 is now ready for use.
Limiter
Output limiters prevent distortion during loud program peaks without affecting normal program levels. This keeps
the devices connected to the SCM410 output from becoming overloaded. Increasing individual or Master controls
on the SCM410 increases average output and, in turn, the amount of limiting.
The limiter may be turned on via the rear panel DIP switch. The default limiter threshold is +16 dBu. As supplied,
the limiter is defeated.
Note: Limiter thresholds can be changed from their factory settings. Refer to the Internal Modifications Addendum.
Equalizer Functions
Low Cut Filter (High-Pass)
Low-cut filters are used to reduce unwanted low frequency sounds such as footsteps, motorized traffic, and to con-
trol proximity effect. The SCM410 has a one-pole, low-cut (high-pass) filter of 6 dB per octave. The low-cut filter al-
lows all frequencies above its cutoff point to pass through unchanged. Frequencies below the cutoff are attenuated
(see Figure 2). The cutoff point is defined as the frequency where the signal has dropped 3 dB relative to the flat,
or bandpass, region. Below the cutoff point, the filter exhibits increasingly more attenuation as the frequency di-
minishes.
FIGURE 2: LOW-CUT FILTER EFFECTS
High-Frequency Shelving
The fixed-frequency equalizer produces a 6 dB boost or cut at 5 kHz and above (see Figure 3). High-frequency
shelving is extremely useful for boosting flat frequency response and tempering sibilant vocal microphones or en-
hancing the sound of off-axis lavalier microphones.

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FIGURE 3: HIGH-FREQUENCY SHELVING EFFECTS
Specifications
Measurement Conditions (unless otherwise specified): Line voltage 120 Vac, 60 Hz (SCM410) or 230 Vac, 50 Hz
(SCM410E); full gain; 1 kHz, one channel activated; source impedances: Mic 150Ω ; terminations: Line/Mic Aux 10
kΩ
Voltage Gain (typical, controls full clockwise)
Output
Input Line Mic Aux
Low-impedance mic (150
Ω )
80 dB 40 dB 68 dB
Inputs
Impedance
Input Designed for use with Actual (typical) Input Clipping Level
Mic 19-600 Ω 1.4 kΩ -14 dBV
Outputs
Impedance
Output Designed for use with Actual (typical) Output Clipping Level
Line ≥5k Ω 300 Ω +22 dBV
Mic ≥600 Ω 3 Ω -20 dBV
Aux ≥10k Ω 1.5 k Ω +12 dBV

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Frequency Response (at 1 kHz , channel controls centered)
50 Hz to 20 kHz ± 2 dB ; −3 dB Corner at 25 kHz
Total Harmonic Distortion
<0.1% at +4 dBu out , 50 Hz to 20 kHz (through 22 Hz to 20 kHz filter; Input at 12 o'clock and Master at 12 o'clock,
all other controls full counterclockwise)
Equivalent Input Noise: (150 Ωsource; A-Weighted)
-127 dBV maximum, -129 dBV typical
Output Noise (channel controls full counterclockwise A-Weighted)
Master full counterclockwise: -101 dBV
Master full clockwise: -67 dBV
Common Mode Rejection
> 70 dBV at 1 kHz
Polarity
All inputs to all outputs are non-inverting
Input Channel Activation
Attack Time 4 ms
Hold Time 0.4 s
Decay Time 0.5 s
Off-Attenuation
13 dB
Overload and Shorting Protection
Shorting outputs, even for prolonged periods, causes no damage. Microphone inputs are not damaged by signals
up to +10 dBV (3V)
Equalization
Low-frequency 6 dB/octave cut, adjustable corner from 25 to 320 Hz
High-Frequency shelving filter, ±6 dB at 5 kHz, rising to ±8 dB at 10 kHz

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Limiter
Type Peak
Threshold ±16 dBu (at output)
Attack Time 2 ms
Recovery Time 300 ms
Indicator Lights red when limiting occurs
Input LEDs
Green on channel activation, red at 6 dB below clipping
Phantom Power
12 V DC open-circuit through 680 Ω resistors
Operating Voltage
SCM410 100-120 V AC rated nominal, 50/60 Hz, 100 mA (maximum)
SCM410E 220-240 V AC rated nominal, 50/60 Hz, 50 mA (maximum)
Mains Inrush Current (230 V AC, SCM410E only)
0.7 A Peak
Temperature Range
Operating Temperature -7° to 49° C (20° to 120° F)
Storage Temperature -29° to 74° C (-20° to 165° F)
Dimensions
44 x 219 x 267 mm (1 ¾ x 8 5/8 x 10 ½ in.), H x W x D
Net Weight
1.75 kg (3.86 lbs)
Certifications
SCM410: UL LISTED to UL 60065 and cUL LISTED to CAN/CSAC22.2 No. 60065-3 Canada.
SCM410E: Conforms to applicable European Union Directives. Low Voltage Directive, 2006/95/EC: Certified to EN
60065. Eligible to bear CE marking. Conforms to European EMC Directive 2004/108/EC. Meets Harmonized Stan-
dards EN55103-1:1996 and EN55103-2:1996 for residential (E1) and light industrial (E2) environments.

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•Conforms to European Regulation (EC) No. 1275/2008, as amended.
The CE Declaration of Conformity can be obtained from Shure Incorporated or any of its European representa-
tives. For contact information please visit www.shure.com
The CE Declaration of Conformity can be obtained from: www.shure.com/europe/compliance
Authorized European representative:
Shure Europe GmbH
Headquarters Europe, Middle East & Africa
Department: EMEA Approval
Jakob-Dieffenbacher-Str. 12
75031 Eppingen, Germany
Phone: [phone]
Fax: [phone]
Email: [email protected]
Replacement Parts
Knob, Channel Gain and Phones (white) 95A8238
Knob, Channel Gain (blue) 95B8238
Line (Power) Cord (SCM800) 95B8389
Line (Power) Cords: SCM262E: 220-240 Vac (EU) 95B8778
Link Cable 95B8889
Fuse, SCM410 (5x20 mm, T 125mA L, 250V, time delay) 80AA730
Fuse, SCM410E (5x20 mm, T 50mA L, 250V, time lag) 80J380
Single Mount Bracket 53A8484
Dual Mount Bracket 53E8484
Link Bars (Bracket) 53B8443
Hardware Kit 90AW8100

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Optional Accessories
Line (Power) Cord, 230-240 Vac (UK) 95A8713
Line Adapter–Converts Balanced Line Level Signals to Microphone Level (50dB
Attenuation)
A15LA
For additional service or parts information, please contact Shure's Service department at 1-800-516-2525. Outside
the United States, please contact your authorized Shure Service Center.
Advanced Functions
WARNING: Battery packs shall not be exposed to excessive heat such as sunshine, fire, or the like.
Logic Connection Specifications
The SCM410 logic functions expand the range of installation and control options. Logic can be used for everything
from simple cough switches to elaborate computer-controlled room systems. (Shure's AMS Update publication
contains additional applications of advanced logic. This publication is available by contacting the Shure Applica-
tions Department.) The following logic functions are available for each channel:
GATE OUT
Follows channel gating and goes to logic “low” (sinks current) when microphone is gated on. 500 mA of current
sinking ability is provided (see Figure 4A).
MUTE IN
Applying logic “low” (from GATE OUT or a switch closure to logic ground) gates channel off (see Figure 4B). Chan-
nel output drops to -∞.
FIGURE 4: LOGIC EQUIVALENT CIRCUIT DIAGRAM
OVERRIDE IN
Applying logic “low” (from GATE OUT or a switch closure to logic ground) forces channel on (see Figure 4B).
When both Mute and Override are activated, Mute takes precedence (see Internal Modifications Addendum for
Override precedence).
LOGIC GROUND

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Logic ground is distinct from audio ground. Make all logic ground connections to this pin, including power supply
ground of external logic circuitry. To avoid switching clicks, do not connect logic ground to audio, chassis or rack
grounds. Logic controls are accessed through the high density DB-15 multi-pin connector on the rear panel (Figure
5). Pin connections are shown in the following table.
FIGURE 5: LOGIC CONNECTOR
Pin No. Logic Function
1 OVERRIDE IN 1
2 OVERRIDE IN 2
3 OVERRIDE IN 3
4 GATE OUT 4
5 LOGIC GROUND
6 GATE OUT 1
7 GATE OUT 2
8 GATE OUT 3
9 NO CONNECTION

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Pin No. Logic Function
10 MUTE IN 4
11 MUTE IN 1
12 MUTE IN 2
13 MUTE IN 3
14 OVERRIDE IN 4
15 NO CONNECTION
Logic Function Pin No.
GATE OUT 1 6
GATE OUT 2 7
GATE OUT 3 8
GATE OUT 4 4
OVERRIDE IN 1 1
OVERRIDE IN 2 2
OVERRIDE IN 3 3
OVERRIDE IN 4 14
MUTE IN 1 11
MUTE IN 2 12
MUTE IN 3 13
MUTE IN 4 10
LOGIC GROUND 5
NO CONNECTION 15
NO CONNECTION 9

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Suggested Logic Applications
This section contains suggestions on the uses of the SCM410's logic capabilities. Note that uses of these func-
tions are not limited to the listed applications. The user is limited only by imagination and creativity. For additional
suggestions and solutions to installation problems, contact the Shure Applications Department.
Cough Button
The talker can turn off his or her microphone during coughing or private conversations by installing an SPST push
button switch between the MUTE IN and Logic Ground pins for each channel to be modified (see Figure 6). When
a channel is muted, no audio is passed. (See Dead Zone on MUTE IN Defeat paragraph in the Internal Modifica
tions Addendum for more information on MUTE IN logic.)
FIGURE 6: COUGH BUTTONS
Chairperson-Controlled Muting
The chairperson can, by activating a switch, silence all other microphones and be heard without interruption. For
operation in this mode, connect all the MUTE IN pins together except that of the chairperson's channel, and wire
an SPST pushbutton or toggle switch between those MUTE IN and Logic Ground pins (see Figure 7). An alterna-
tive to a switch is to connect the chairperson's GATE OUT to the MUTE IN of other channels. When the
chairperson's microphone activates, all other microphones mute.

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FIGURE 7: CHAIRPERSON-CONTROLLED MUTING
Remote Channel-On Indicators
Remote indicators can be used to indicate when a talker's microphone is on. Connect the LEDs and a 5-volt sup-
ply to the GATE OUT pins (See Figure 8). To avoid switching clicks in the audio output, do not ground the power
supply negative terminal in the audio system or rack ground.
Important: If a single cable is used for the microphone audio signal and the LED dc power, separate shielded
pairs must be used. Failure to carry the dc power on a shielded pair may result in audible clicking due to capacitive
coupling between the dc power lines and microphone lines.
FIGURE 8: REMOTE CHANNEL-ON INDICATORS
Disabling the Gating Function (Bypass)
To keep certain microphones on at all times, wire the desired microphone channel's OVERRIDE IN pins together
to the Logic Ground pin. The selected channels now function as they would in a non-automatic mixer (see Figure
9). To perform this modification internally on the mixer, refer to the Shorting Override In to Logic Ground Internally
paragraph in the Internal Modifications Addendum.