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WARNING: Voltages in this equipment are hazardous to life. No user-serviceable parts inside. Refer all servicing to qualified service personnel. The safety certifications do not apply when the operating voltage is changed from the factory setting.
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-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, and SCM800.
Each input channel has a two-band equalizer and three logic terminals. The equalizer reduces unwanted low-frequency audio pickup and makes different microphone types-lavaliers, boundary and handheldsound 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.
The operating concept behind the SCM410 Automatic Mixer is Shure's proprietary IntelliMix® circuitry. Intellimix delivers seamless automatic mixing by combining three separate functions:
IntelliMix is a registered trademark of Shure Incorporated.
1 Microphone Channel Gain Controls 1 - 4
Allows adjustment 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 rolloff (high pass), reducing presence of undesirable low-frequency 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 coloration 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.
8 POWER Switch
Turns the mixer on and off.
Note: Country dependant
1 Power Connector
Unit is energized when the power cord is plugged into a 100-120 Vac (SCM410) or 220-240 Vac (SCM410E) power source. NOTE: There is no power On/Off switch on this mixer.
2 DIP Switch
The 4-position DIP switch provides additional functions. Refer to the “DIP Switch Functions”section.
3 Microphone Logic Connector
High density DB-15 male connector provides connection to GATE OUT, MUTE IN, and OVERRIDE IN logic terminals on each channel. Refer to the “Advanced Functions” section.
Note: This is not a VGA monitor port.
4 AUX OUT Phono Connector
Feeds consumer-level audio equipment, such as a tape recorder, VCR, or video camera. Not affected by MIC/LINE switch.
5 MIC/LINE XLR OUTPUT Connector
Can be set for microphone or line-level output via a DIP switch.
6 LINK IN/OUT Connector
Permits multiple SCM410/E, FP410, SCM810, SCM800, or AMS8100 mixers to be linked, creating additional inputs.
7 MIC LEVEL XLR INPUT Connectors
Active balanced microphone-level XLR inputs. For instructions on how to modify the level of these inputs, refer to the “Internal Modifications” Addendum.
The rear panel DIP switches, shown in Figure 1, provide the functions listed in the table below.
| Last Mic Lock-On | XLR Output Level | Limiter | 12V Phantom Power | |
| Switch Number | 1 | 2 | 3 | 4 |
| Switch Up | All mics off after hold time | Mic Level | ON | ON |
| Switch Down | ON* | Line Level | OFF* | OFF* |
* Factory setting
Last Mic Lock-On
Keeps the most recently activated microphone turned on until another microphone is activated. When defeated, microphones turn off after their default hold time. XLR Output Level: Sets the level of the XLR output to line or microphone level. Make sure the output level matches the input level of the device connected to the SCM410.
Note: The output level does not affect the auxiliary output (AUX OUT) level.
Limiter
Activates the output limiter and sets it to a default threshold of +16 dBu (see Internal Modifications Addendum for other threshold settings).
12V Phantom Power
When this switch is in the ON position, the SCM410 provides 12Vdc phantom power to each XLR microphone input. This function is particularly useful when using condenser microphones, since most condenser microphones require phantom power.
Note: Phantom power does not affect the operation of balanced dynamic microphones. They can be connected to the SCM410 in combination with condenser microphones that use phantom power. For instructions on how to disable phantom power by channel, refer to the Internal Modifications Addendum.
The SCM410 is supplied with hardware for mounting one or two units to a 19-inch audio equipment rack. The hardware can also be used to rack mount other Shure products, including the SCM268, SCM262, DFR11EQ, and the DP11EQ.
INSTALLING HALF RACK MOUNTING BRACKETS
RACK MOUNTING A SINGLE SCM410/E MIXER
INSTALLING STRADDLE BRACKETS
INSTALLING FULL RACK MOUNTING BRACKETS
RACK MOUNTING DUAL SCM410/E MIXERS
Adhere the four (4) supplied rubber feet to the bottom of the mixer at each corner. This will keep it from sliding and protect the table surface.
ATTACHING RUBBER FEET FOR TABLE-TOP MOUNTING
INSTALLING STRADDLE BRACKETS FOR TOP MOUNTING
SECURING MIXER TO TOP MOUNTING SURFACE
Note: The hardware provided is for attachment to wood. Other surfaces require the use of appropriate hardware rated for 15 lbs. or more.
INSTALLING STRADDLE BRACKETS FOR HANG MOUNTING
SECURING MIXER TO BOTTOM MOUNTING SURFACE
If more than four inputs are needed, multiple Shure SCM410, FP410, or SCM810 mixers can be linked by connecting the LINK OUT of the first mixer to the LINK IN of the next mixer, and so on. See Figure 2. Leave the LINK IN jack of the first mixer and the LINK OUT jack of the last mixer unconnected.
When properly linked, the mixers will operate as a system. Automatic mixing functions will be shared by all units. All input signals appear at all linked mixer outputs. Each mixer's Master level control only controls its own output. However, actual off-attenuation will increase as more mixers are linked. This reduces excessive noise and reverberation contributed by the increased number of microphones.
Important: When using logic terminals on linked mixers, connect the LOGIC GROUND terminals of each unit together.
Note: SCM410 link connections are unbalanced. To minimize hum and noise, avoid using longer link cables. Use high quality, shielded cable, and keep them away from sources of magnetic or electrical noise, such as power transformers or light dimmers. To minimize ground currents, make sure linked mixers are connected to the same AC power mains.
FIGURE 1: LINKED SCM410 AND SCM810 MIXERS
Output limiters prevent distortion during loud program peaks without affecting normal program levels. This keeps the devices connected to the SCM410 output from becoming overloaded. Increasing individual or Master controls on the SCM410 increases average output and, in turn, the amount of limiting.
The limiter may be turned on via the rear panel DIP switch. The default limiter threshold is +16 dBu. As supplied, the limiter is defeated.
Note: Limiter thresholds can be changed from their factory settings. Refer to the Internal Modifications Addendum.
Low Cut Filter (High-Pass)
Low-cut filters are used to reduce unwanted low frequency sounds such as footsteps, motorized traffic, and to control proximity effect. The SCM410 has a one-pole, low-cut (high-pass) filter of 6 dB per octave. The low-cut filter allows all frequencies above its cutoff point to pass through unchanged. Frequencies below the cutoff are attenuated (see Figure 2). The cutoff point is defined as the frequency where the signal has dropped 3 dB relative to the flat, or bandpass, region. Below the cutoff point, the filter exhibits increasingly more attenuation as the frequency diminishes.
FIGURE 2: LOW-CUT FILTER EFFECTS
High-Frequency Shelving
The fixed-frequency equalizer produces a 6 dB boost or cut at 5 kHz and above (see Figure 3). High-frequency shelving is extremely useful for boosting flat frequency response and tempering sibilant vocal microphones or enhancing the sound of off-axis lavalier microphones.
FIGURE 3: HIGH-FREQUENCY SHELVING EFFECTS
Measurement Conditions (unless otherwise specified): Line voltage 120 Vac, 60 Hz (SCM410) or 230 Vac, 50 Hz (SCM410E); full gain; 1 kHz, one channel activated; source impedances: Mic 150Ω ; terminations: Line/Mic Aux 10 kΩ
| Output | |||
| Input | Line | Mic | Aux |
| Low-impedance mic (150 Ω ) | 80 dB | 40 dB | 68 dB |
| Impedance | |||
| Input | Designed for use with | Actual (typical) | Input Clipping Level |
| Mic | 19-600 Ω | 1.4 kΩ | -14 dBV |
| Impedance | |||
| Output | Designed for use with | Actual (typical) | Output Clipping Level |
| Line | ≥5k Ω | 300 Ω | +22 dBV |
| Mic | ≥600 Ω | 3 Ω | -20 dBV |
| Aux | ≥10k Ω | 1.5 k Ω | +12 dBV |
50 Hz to 20 kHz ± 2 dB ; −3 dB Corner at 25 kHz
<0.1% at +4 dBu out , 50 Hz to 20 kHz (through 22 Hz to 20 kHz filter; Input at 12 o'clock and Master at 12 o'clock, all other controls full counterclockwise)
-127 dBV maximum, -129 dBV typical
| Master full counterclockwise: | -101 dBV |
| Master full clockwise: | -67 dBV |
> 70 dBV at 1 kHz
All inputs to all outputs are non-inverting
| Attack Time | 4 ms |
| Hold Time | 0.4 s |
| Decay Time | 0.5 s |
13 dB
Shorting outputs, even for prolonged periods, causes no damage. Microphone inputs are not damaged by signals up to +10 dBV (3V)
| Low-frequency | 6 dB/octave cut, adjustable corner from 25 to 320 Hz |
| High-Frequency | shelving filter, ±6 dB at 5 kHz, rising to ±8 dB at 10 kHz |
| Type | Peak |
| Threshold | ±16 dBu (at output) |
| Attack Time | 2 ms |
| Recovery Time | 300 ms |
| Indicator | Lights red when limiting occurs |
Green on channel activation, red at 6 dB below clipping
12 V DC open-circuit through 680 Ω resistors
| SCM410 | 100-120 V AC rated nominal, 50/60 Hz, 100 mA (maximum) |
| SCM410E | 220-240 V AC rated nominal, 50/60 Hz, 50 mA (maximum) |
0.7 A Peak
| Operating Temperature | -7° to 49° C (20° to 120° F) |
| Storage Temperature | -29° to 74° C (-20° to 165° F) |
44 x 219 x 267 mm (1 ¾ x 8 5/8 x 10 ½ in.), H x W x D
1.75 kg (3.86 lbs)
SCM410: UL LISTED to UL 60065 and cUL LISTED to CAN/CSAC22.2 No. 60065-3 Canada.
SCM410E: Conforms to applicable European Union Directives. Low Voltage Directive, 2006/95/EC: Certified to EN 60065. Eligible to bear CE marking. Conforms to European EMC Directive 2004/108/EC. Meets Harmonized Standards EN55103-1:1996 and EN55103-2:1996 for residential (E1) and light industrial (E2) environments.
The CE Declaration of Conformity can be obtained from Shure Incorporated or any of its European representatives. For contact information please visit www.shure.com
The CE Declaration of Conformity can be obtained from: www.shure.com/europe/compliance
Authorized European representative:
Shure Europe GmbH
Headquarters Europe, Middle East & Africa
Department: EMEA Approval
Jakob-Dieffenbacher-Str. 12
75031 Eppingen, Germany
Phone: +49-7262-92 49 0
Fax: +49-7262-92 49 11 4
Email: info@shure.de
| Knob, Channel Gain and Phones (white) | 95A8238 |
| Knob, Channel Gain (blue) | 95B8238 |
| Line (Power) Cord (SCM800) | 95B8389 |
| Line (Power) Cords: SCM262E: 220-240 Vac (EU) | 95B8778 |
| Link Cable | 95B8889 |
| Fuse, SCM410 (5x20 mm, T 125mA L, 250V, time delay) | 80AA730 |
| Fuse, SCM410E (5x20 mm, T 50mA L, 250V, time lag) | 80J380 |
| Single Mount Bracket | 53A8484 |
| Dual Mount Bracket | 53E8484 |
| Link Bars (Bracket) | 53B8443 |
| Hardware Kit | 90AW8100 |
| Line (Power) Cord, 230-240 Vac (UK) | 95A8713 |
| Line Adapter–Converts Balanced Line Level Signals to Microphone Level (50dB Attenuation) | A15LA |
For additional service or parts information, please contact Shure's Service department at 1-800-516-2525. Outside the United States, please contact your authorized Shure Service Center.
WARNING: Battery packs shall not be exposed to excessive heat such as sunshine, fire, or the like.
The SCM410 logic functions expand the range of installation and control options. Logic can be used for everything from simple cough switches to elaborate computer-controlled room systems. (Shure's AMS Update publication contains additional applications of advanced logic. This publication is available by contacting the Shure Applications Department.) The following logic functions are available for each channel:
GATE OUT
Follows channel gating and goes to logic “low” (sinks current) when microphone is gated on. 500 mA of current sinking ability is provided (see Figure 4A).
MUTE IN
Applying logic “low” (from GATE OUT or a switch closure to logic ground) gates channel off (see Figure 4B). Channel output drops to -∞.
FIGURE 4: LOGIC EQUIVALENT CIRCUIT DIAGRAM
OVERRIDE IN
Applying logic “low” (from GATE OUT or a switch closure to logic ground) forces channel on (see Figure 4B). When both Mute and Override are activated, Mute takes precedence (see Internal Modifications Addendum for Override precedence).
LOGIC GROUND
Logic ground is distinct from audio ground. Make all logic ground connections to this pin, including power supply ground of external logic circuitry. To avoid switching clicks, do not connect logic ground to audio, chassis or rack grounds. Logic controls are accessed through the high density DB-15 multi-pin connector on the rear panel (Figure 5). Pin connections are shown in the following table.
FIGURE 5: LOGIC CONNECTOR
| Pin No. | Logic Function |
|---|---|
| 1 | OVERRIDE IN 1 |
| 2 | OVERRIDE IN 2 |
| 3 | OVERRIDE IN 3 |
| 4 | GATE OUT 4 |
| 5 | LOGIC GROUND |
| 6 | GATE OUT 1 |
| 7 | GATE OUT 2 |
| 8 | GATE OUT 3 |
| 9 | NO CONNECTION |
| 10 | MUTE IN 4 |
| 11 | MUTE IN 1 |
| 12 | MUTE IN 2 |
| 13 | MUTE IN 3 |
| 14 | OVERRIDE IN 4 |
| 15 | NO CONNECTION |
| Logic Function | Pin No. |
|---|---|
| GATE OUT 1 | 6 |
| GATE OUT 2 | 7 |
| GATE OUT 3 | 8 |
| GATE OUT 4 | 4 |
| OVERRIDE IN 1 | 1 |
| OVERRIDE IN 2 | 2 |
| OVERRIDE IN 3 | 3 |
| OVERRIDE IN 4 | 14 |
| MUTE IN 1 | 11 |
| MUTE IN 2 | 12 |
| MUTE IN 3 | 13 |
| MUTE IN 4 | 10 |
| LOGIC GROUND | 5 |
| NO CONNECTION | 15 |
| NO CONNECTION | 9 |
This section contains suggestions on the uses of the SCM410's logic capabilities. Note that uses of these functions are not limited to the listed applications. The user is limited only by imagination and creativity. For additional suggestions and solutions to installation problems, contact the Shure Applications Department.
The talker can turn off his or her microphone during coughing or private conversations by installing an SPST push button switch between the MUTE IN and Logic Ground pins for each channel to be modified (see Figure 6). When a channel is muted, no audio is passed. (See Dead Zone on MUTE IN Defeat paragraph in the Internal Modifications Addendum for more information on MUTE IN logic.)
FIGURE 6: COUGH BUTTONS
FIGURE 7: CHAIRPERSON-CONTROLLED MUTING
Important: If a single cable is used for the microphone audio signal and the LED dc power, separate shielded pairs must be used. Failure to carry the dc power on a shielded pair may result in audible clicking due to capacitive coupling between the dc power lines and microphone lines.
FIGURE 8: REMOTE CHANNEL-ON INDICATORS
To keep certain microphones on at all times, wire the desired microphone channel's OVERRIDE IN pins together to the Logic Ground pin. The selected channels now function as they would in a non-automatic mixer (see Figure 9). To perform this modification internally on the mixer, refer to the Shorting Override In to Logic Ground Internally paragraph in the Internal Modifications Addendum.
FIGURE 9: GATING BYPASS
MaxBus attempts to activate only one microphone per sound source.
Muting a microphone channel prevents its audio from appearing at the mixer's output. However, the muted microphone still communicates with other mic channels via MaxBus. A sound source picked up by a muted microphone will not activate other microphones.
Sound sources that may cause unwanted microphone channel activation include:
The SCM410 can prevent these and similar sounds from activating microphones as follows:
FIGURE 10: INHIBITING GATING FOR UNWANTED SOUNDS
Some applications require a loudspeaker to be placed near each talker to provide audio reinforcement, or to permit telephone conversation or conference monitoring. Each loudspeaker can cause feedback unless it is automatically switched off when the talker near it speaks. To provide this function, connect the GATE OUT terminal of each channel to a separate loudspeaker muting relay (See Figure 11). Recommended relays are Radio Shack 275-248, Omron G2R-14-DC12 (Digi-Key number Z745-ND), Potter & Brumfield R10-E1Y2-V185 (Newark number 45F106), or equivalent.
Note: A diode across each relay coil is required to suppress inductive voltage spikes which may damage the SCM410. An existing sound system using 24-volt relays can be used with the SCM410 without modification if the relay coil current draw is under 500 mA.
FIGURE 11: LOUDSPEAKER MUTING
Normally, when several people talk, each microphone gates on so that no speech is missed. In “filibuster” mode, a microphone remains gated on until the talker pauses long enough for that microphone to gate off. No other microphone can gate on until that microphone gates off. This prevents talkers from being interrupted.
To establish filibuster mode, refer to Figure 12 and proceed as follows:
Note: To prevent high-frequency oscillation, do not wire a GATE OUT pin to a MUTE IN pin on the same channel unless the Mute to Inhibit modification has been made.
FIGURE 12: FILIBUSTER MODE
For information on the inhibit function, refer to the Internal Modifications Addendum.
The level of the Aux or Master output can be controlled from an external VCA (Voltage Controlled Amplifier) such as the RU-VCA1 from Radio Design Labs (Tel. 1-800-281-2683, or www.rdlnet.com). To connect a VCA to the SCM410, proceed as follows:
FIGURE 13: DIODE ISOLATION OF LOGIC CONTROLS
Note: For information on logic gate use, refer to the TTL Cookbook and CMOS Cookbook, both by D. Lancaster, Howard Sams Publishing Co.
FIGURE 14: 15V CMOS
The SCM410 logic pins can interface with custom-designed digital control circuitry or microcomputers for unlimited possibilities of system control functions.
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