Shure SCM410E - Manual (Page 3)

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DESCRIPTION
The Shure Model SCM410/E is a four-channel automatic mi-
crophone mixer designed for use in sound reinforcement, au-
dio recording, and broadcast applications. The SCM410 dra-
matically improves audio quality in any application where mul-
tiple 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, SCM800, and AMS8100 mixers. Each input channel has a two-band equalizer and three logic
terminals. The equalizer reduces unwanted low-frequency au-
dio pickup and makes different microphone types—lavaliers,
boundary and handheld—sound 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 ac-
tivated–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 seam-
less 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 acti-
vated 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 mi-
crophone open until another microphone is activated. With-
out 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.
FRONT PANEL
MODEL SCM410 FRONT PANEL
FIGURE 1
1. Microphone Channel Gain Controls 1 - 4: Allows adjust-
ment of microphone gain.
2. Input LED 1 - 4: Lights green when channel is active; lights
red at 6 dB below clipping level.
3. Low-Cut Filter 1 - 4: Provides adjustable low-frequency rol-
loff (high pass), reducing presence of undesirable low-fre-
quency signals.
4. 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 col-
oration in lavalier microphones.
5. 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.
6. MASTER Level Control: Controls overall output level.
7. POWER LED: Lights green when mixer is plugged into a
power source.
*U.S. Patents 4,658,425 and 5,297,210.
IntelliMix is a registered trademark of Shure Brothers Incorporated.