Mixer User Manual

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DESCRIPTION
The Shure Model SCM410/E is a four-channel automatic microphone
mixer for use in sound reinforcement, audio recording, and broadcast
applications. The SCM410 dramatically improves audio quality in any
application where multiple microphones are required. Any low-imped-
ance 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 termi-
nals. The equalizer reduces unwanted low-frequency audio pickup and
makes different microphone types-lavaliers, boundary and handheld-
sound similar. The logic terminals can be used to control external de-
vices.
The SCM410 operates on 100-120 Vac power and the SCM410E op-
erates 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 Attenuated)
• 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
• 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 patented* IntelliMix
®
circuitry. Intellimix delivers seamless au-
tomatic mixing by combining three separate functions:
• Noise Adaptive Threshold. Distinguishes between constant back-
ground 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.
*U.S. Patents 4,658,425 and 5,297,210. IntelliMix is a
registered trademark of Shure Incorporated.
FRONT PANEL
 Microphone Channel Gain Controls 1 - 4: Allows adjust-
ment 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 compensate 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 illu-
minates when the output is 6 dB below clipping. The last LED
indicates limiter action.
 MASTER Level Control: Controls overall output level.
 POWER LED: Lights green when mixer is plugged into a
power source.
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