Shure SCM410E manual Description, Features, Operating Principles, Model SCM410 Front Panel

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 typesÐlavaliers, boundary and handheldÐsound 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 ªhearº 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.

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