Shure SCM820 Digital IntelliMix User manual

SCM820
SCM820 Digital IntelliMix Automatic Mixer
®
The Shure digital automatic mixer, SCM820, user guide.
Version: 4.0 (2021-C)

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Table of Contents
SCM820 SCM820 Digital IntelliMix® Automatic Mixer 4
Overview 4
IntelliMix® Operating Principles 4
Mixer Modes 4
Dual Mixer Operation 5
DFR and Audio Processing 5
Model Variations 5
Hardware Interface 6
Front Panel 6
Rear Panel 8
Signal Path Diagram 11
Operating the Mixer 12
Front Panel Modes 12
Audio Mute and Bypass 13
Monitoring 13
SCM820 Application 15
System Requirements 16
Accessing the SCM820 application 16
Installation 17
Power 17
Rackmounting 17
Typical Audio Connections 18
Configuring the Inputs and Outputs 19
Setting IntelliMix 23
Mixer Mode Descriptions 23
IntelliMix Parameters 26
Selecting the Mixer Mode 26
Single or Dual Mixer Operation 27
Networking 27
Network Overview 28
Digital Audio Networking 29
Dante Software by Audinate 34
Dante Controller 34
Dante Virtual Soundcard 34
Application Examples and Advanced Mixer Settings 34
Creating a Link Group 34
Integrating with Other Systems 35
Advanced Mixer Settings 36
Web conferencing 37
Digital Feedback Reduction (DFR) 38
Function 38
Basic DFR Setup 38
Filter Width 39
SCM820 Application 39
Navigation Bar 40
Input Tab 41
Intellimix Tab 43
Digital Feedback Reduction (DFR) Tab 45
Output Tab 46
Preferences Tab 47
Troubleshooting 49
Front-Panel Error Messages 52
Accessories 52
Furnished Accessories 52
Specifications 53
IP Ports and Protocols 56
Connector Diagrams 57

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IMPORTANT SAFETY INSTRUCTIONS 57
Important Product Information 58
Information to the user 59
Patent Notice 59

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SCM820 
SCM820 Digital IntelliMix Automatic Mixer
Overview
TheShureSCM820isan8-channeldigitalautomaticmixerdesignedforuseinspeechapplications,includingsoundreinforce-
ment, broadcasting and audio recording. It dramatically improves audio quality in any application where multiple microphones
are required. The mixer uses IntelliMix technology to select channels to open to the mix bus, while attenuating other channels.
The mixing mode is selectable to allow a range of automatic mixing styles.
IntelliMix Operating Principles
Expanding upon Shure's classic SCM810 IntelliMix technology, the digital SCM820 delivers seamless automatic mixing by
combining the following functions:
Noise Adaptive Threshold (NAT) manages the audio system by distinguishing between dynamic audio (such as speech)
and the noise floor (such as air conditioning). It continuously adjusts the activation threshold, so that only speech levels
louder than the background noise open a channel.
MaxBus ensures that only one channel is opened per sound source, reducing comb filtering for clear, intelligible speech.
Number of Open Microphones Attenuation (NOMA)attenuatessystemgainasadditionalchannelsareopened,provid-
ing consistent output levels and better gain before feedback.
Maintainstheperceivedambientsoundtoachieveanaturalsoundingaudioprogramevenduringlongpausesinconver-
sation.
Mixer Modes
The mixer operates in one of five Mix Modes: Classic, Smooth, Extreme, Custom or Manual. The first three are factory settings
that offer a range of reliable automixing styles. IntelliMix is configurable in Custom mode and turned off in Manual mode.
Classic
ClassicmodeemulatesthedefaultsettingsoftheclassicShureSCM810automixer.Itisrenownedforfast-acting,seam-
less channel gating and consistent perceived ambient sound levels.
Smooth
Smooth mode dynamically balances system gain between open and closed channels. The system gain remains consistent
by distributing gain across channels to equal one open channel. This mode incorporates IntelliMix operating principles into
a gain sharing mixing style.
Extreme
Extreme is an aggressive variation of Classic mode, configured to achieve maximum gain before feedback by completely
attenuating closed channels.
Custom
Custom mode allows individual IntelliMix parameters to be fine-tuned and tailored from the GUI.
Manual
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Manual mode deactivates IntelliMix to operate as a standard mixer. Channel and mix equalization, output limiter and mix
bus routing are still active in this setting.
Dual Mixer Operation
The SCM820 can operate as a single or dual mixer:
Single Mixer: Channels are routed to a single mix bus that sends the same audio to both Mix A and B outputs. This allows the
same program to be sent to different rooms or recording applications. Output gain, parametric equalizer and limiter can be set
separately for each mix.
Dual Mixer: Two separate buses provide independent automixes for each mix output. This allows two entirely different mixes
to result from the same set of inputs. This is useful when the mixer is being used for two applications. For example, set Mix A to
Classic mode for sound reinforcement, and set Mix B to Smooth for a broadcast feed. As a dual mixer, channels can be routed
to Mix A, Mix B, Mix A and B, or neither mix bus.
DFR and Audio Processing
TheSCM820featurestwochannelsofDigitalFeedbackReducer(DFR).DFRusesShure’spatentedAdaptiveNotchFilteral-
gorithm to detect feedback and deploy up to 16 narrow-band notch filters, dramatically improving gain-before-feedback in a
sound reinforcement system. DFR can be applied to any two channels of the SCM820, including the mix outputs.
Additionally, the mixer provides adjustable input equalization, limiting and a parametric output EQ to optimize the sound in any
application.
Model Variations
The following table describes the four SCM820 model variations:
Model Variations
Model
Description
Connector Type Network Card
SCM820 Block Standard Ethernet
SCM820-DAN Block Dante Digital Audio
SCM820-DB25 DB25 Standard Ethernet
SCM820-DAN-DB25 DB25 Dante Digital Audio

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Upgrading to Dante
You can add digital networking capabilities to a standard SCM820 using the Dante Network Interface Card (A820-NIC-DAN).
The card replaces the standard Ethernet port with 2 Dante network ports. This upgrade should only be installed by qualified
service personnel.
Update the firmware on the SCM820 before installing the Dante Network Interface Card. Visit www.shure.com for more details.
Hardware Interface
Front Panel
①Channel Mode Selection
PressthebuttontoselectthefunctionofthechannelknobsandmonitorLEDrings.SeetheAudioSignalAdjustmentsec-
tion for details on each mode.
②Assignable Channel Knob
Adjusts settings and status for each input:
Rotate: Adjusts a setting.
Momentary Press: Solos the channel to the headphone output.
Press and Hold: Mutes the audio or bypasses the EQ setting.
③Monitor LED Ring
13 LED segments display gain setting, input signal meter, IntelliMix gain meter, channel solo, or EQ setting.
④Channel Status LED
LED Channel Status
Off Channel is closed (attenuated in the automix).
Green Channel is open (selected in the automix).
Amber Channel EQ is bypassed.
Flicker Red Signal is clipping. Set the channel to a lower input gain level.
Solid Red Channel is muted.
⑤Auxiliary Input Jack (1/8")

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Unbalanced aux input sums left and right channels to mono. Front and back panel aux inputs are summed to a mono signal
and routed without automixing to the mix outputs.
⑥Master Output Knob
Adjusts settings and status of the mix outputs. See Front Panel Modes for details.
Rotate: Adjusts output gain or limiter threshold.
Momentary Press: Overrides a soloed channel to return the mix to the headphone output.
Press and Hold: Mutes the audio or bypasses the limiter.
⑦Master LED Ring
Displaysgainsettingorlimiterthreshold.AsingleLEDrepresentseachmixerwhentheyarebothselectedbutsettodiffer-
ent levels.
⑧Master Mode Selection
Selects the function (gain or limiter) of the master knob and LED ring.
⑨Mix Select Button
Selects Mix A, Mix B, or both for adjustment with the master knob and monitoring on the LED ring and headphone output.
Note: When both Mix A and Mix B are selected, the headphone output only monitors Mix A.
⑩Mix Status Indicator
LED Mix Status
Green Mix is selected for adjustment and listening on the headphone output.
Amber Limiter is bypassed.
Red Mix is muted.
⑪Audio Output Meters
Monitor the output signal level and limiter threshold for mix A and B.
⑫LIM (Limiter) LEDs
Illuminate amber when the audio levels exceed the limiter threshold.
⑬System Status Indicators
The LEDs illuminate to indicate system settings:
LED Color Status
power Green Unit is powered on.
ethernet Green Unit is connected to a network.
network audio Green All connected receive channels are OK (receiving digital audio
as expected).

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LED Color Status
Flashing Green
Oneormoreconnectedreceivechannelsexperiencingasub-
scriptionerrororisunresolved(transmittingdeviceisoff,dis-
connected, renamed or has incorrect network setting).
Red Clock synchronization problem.
Off Noreceivechannelsconnected(routinghasnotbeenestab-
lished).
automix link
Green Two or more mixers are connected in a link group.
Flashing Green Link Group is configuring.
Off Mixer is in standalone mode.
dual mixer
Green Mixer is set to Dual Mixer operation.
Off Mixer is set to Single Mixer operation.
lockout
Red Front panel controls are locked.
Flashing Red An adjustment is attempted in lockout mode.
⑭Headphone Volume Knob
Adjust the volume of the headphone output.
⑮Headphone Output Jack (1/4 in.)
Monitor a mix or a soloed channel.
Rear Panel
①Power Switch
Turns the unit on or off.

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②AC Power Jack
Supplies AC power to the mixer when plugged into a power source.
③Mix A and Mix B Outputs
Active balanced outputs connect to amplifiers, DSP, mixer, or recording device.
④Auxiliary Input Jack
Unbalanced aux input sums left and right channels to mono. Front and back panel aux inputs are summed to a mono signal
and routed without automixing to the mix outputs.
⑤ Channel Inputs 1–8
Active-balanced microphone- or line-level inputs.
Block Connectors
Audio +
Audio−
Audio ground
gate
Logic gate out
mute
Logic mute in
ovrd
Logic override in
gnd
Logic ground
DB25 Connector
Pins
Audio plus, audio negative and audio ground. See Specifications for details.
⑥ Direct Outputs 1–8
Each channel has a dedicated, impedance-balanced direct output on the back panel that can be selected from one of five
stages in the signal path. See Configuring the Inputs and Outputs for details on direct output routing.

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⑦ Chassis Ground Screw 1–8
Provides an optional connection for microphone shield wire to chassis ground.
⑧IntelliMix Select Buttons
Scrolls through IntelliMix presets for each mix output. When dual mixer is off, the A button sets the mode for both Mix A and
Mix B.
⑨Dual Mixer Button
Sets the SCM820 as a dual mixer, indicated by the green LED.
⑩Channel Select Button and Display
Presstoselectasinglechannel(1–8)orallchannels(A) when changing input gain or phantom power.
When all channels are selected (A), Input Level and Phantom Power LED indicators only illuminate if all channels have the
same setting.
L is displayed when the mixer is in lockout mode.
⑪Input Gain Selection and LED Indicator
Sets the analog input gain level for the selected channel(s), illuminating the green LED. All LEDs are off when the channel's
audio source is set to Network from the GUI.
⑫Phantom Power Button and LED Indicator
Supplies 48 VDC phantom power to the selected channel(s), illuminating the green LED. Phantom Power is disabled in the
line (+0dB) gain setting.
⑬Auto Link Button and LED Indicator
EnablesnetworkedSCM820-DANmixerstoautomaticallyformalinkgroup.LinkGroupsenablealargeraudiomixbyin-
corporating inputs from two or more mixers. See Link Groups for more details.
⑭Lockout Button and LED Indicator
Hold for five seconds to disable front and back panel controls. The front panel lockoutLEDilluminatesred(flashingreddur-
ing an adjustment attempt) and the back panel channel display shows L.
⑮Reset Button
Press and hold for five seconds to reboot the mixer with default system settings restored.
⑯Network Ports
RJ-45 jacks for network connection.
⑰Network Status LED (Green)
Off = no network link
On = network link established
Flashing = network link active
⑱Network Speed LED (Amber)