Description – Shure Four Channel Automatic Microphone SCM410 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

ᕡ Microphone Channel Gain Controls 1 - 4: Allows adjust-

ment of microphone gain.

ᕢ Input LED 1 - 4: Lights green when channel is active; lights

red at 6 dB below clipping level.

ᕣ Low-Cut Filter 1 - 4: Provides adjustable low-frequency rolloff

(high pass), reducing presence of undesirable low-frequency

signals.

ᕤ 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.

ᕥ 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.

ᕦ MASTER Level Control: Controls overall output level.

ᕧ POWER LED: Lights green when mixer is plugged into a

power source.

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