This symbol indicates that dangerous voltage constituting a risk of electric shock is present within this unit. This symbol indicates that there are important operating and maintenance instructions in the literature accompanying this unit. No user-serviceable parts inside. Refer all servicing to qualified service personnel.
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This symbol indicates that dangerous voltage constituting a risk of electric shock is present within this unit. This symbol indicates that there are important operating and maintenance instructions in the literature accompanying this unit.
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 SCM dramatically improves audio quality in any application where multiple microphones are required. 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 handheld-sound similar.
The logic terminals can be used to control external devices. Each mixer is supplied with a power cord, rack-mounting hardware, and a link cable. IntelliMix delivers seamless automatic mixing by combining three separate functions:.
The rear-panel DIP switch provides the following setup options. The positions shown in bold type are the factory settings. In Manual mode, functions as a standard 8x1 mixer. Last Mic Lock-On: Last Mic Lock-On feature keeps the most recently activated microphone turned on until a newly activated microphone takes its place.
When defeated, microphones turn off after their preset hold time. Hold Time: Adjusts the time an activated microphone which is not locked on remains on after the talker stops talking. Settings are 0. With the 15 dB setting, an unused microphone is 15 dB lower in level than when it is activated. Limiter Threshold: Changes the output limiter threshold. To mount the SCM in a standard mm inch audio equipment rack, slide the mixer into the rack and secure it with the supplied Phillips head screws, as shown in Figure 4.
Use all four screws. The output limiter prevents distortion during loud program peaks without affecting normal program levels. Increasing the individual channel or Master Gain controls will increase the average output and, in turn, the amount of limiting. As supplied, the output limiter is defeated. Refer to the Internal Modifications section. The low-cut or high-pass filter allows all frequencies above its cutoff point to pass from filter input to filter output without attenuation, while frequencies below the cutoff are attenuated see Figure 6.
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.
The SCM has a one-pole, low-cut high-pass filter of 6 dB per octave. Low-cut filters are ideally used for attenuating, or rolling off, the audio signal where extraneous noise, excessive proximity effect, or other unwanted material is present. For example, the low-frequency vibration cause by footsteps and vehicle traffic can be transmitted through microphone stands to the microphone, and then into the sound system.
These frequencies, typically ranging from 5 to 80 Hz, are generally not desirable. The fixed-frequency equalizer produces a 6 dB boost or cut at 5 kHz and above see Figure 7.
High-frequency shelving is extremely useful for boosting flat frequency response, tempering very sibilant vocal microphones, or enhancing the sound of off-axis lavalier microphones. This activates all microphone inputs, so every possible feedback path is open. Remember that the input of an automatic mixer drops by 3 dB every time the number activated inputs doubles. For most applications, no additional adjustments are required. Such a configuration can provide up to microphone inputs.
As long as the link jacks of all mixers are connected out-to-in, sequentially, leaving one Link In and one Link Out jack unconnected , the automatic mixing functions will be shared by all units. All input signals appear at all linked mixer outputs. The output controls and functions of each linked mixer are post-link and do not affect the signals appearing at other linked mixer outputs.
Each mixer's Master level control only controls its own output. Each output can be used independently. This reduces excessive noise and reverberation contributed by the increased number of attenuated microphones. In a linked system, the Aux input of any mixer appears at each linked mixer's output. See Internal Modifications to defeat the linking of Aux signals. Switching clicks may result if this is not done. Set to the Global position, all input channels appear at that mixer's output.
Set to the Local position, only its own eight input channels appear at that mixer's output. The Master level control, in any mode, only controls the level of its own output. The output level of each mixer is affected only by its own Master control. An example of the possibilities of this setup is shown in Figure 9 Here two SCMs are set to Local, and the resulting sound distribution provides local sound reinforcement while avoiding feedback. The following table summarizes the mixer settings.
Additional link cables are available as Shure Part No. Shorting outputs, even for prolonged periods, causes no damage. Microphone inputs are not damaged by signals up to 3 V; Lines and Monitor inputs by signals up to 20 V. For additional service or parts information, please contact Shure's Service department at This product meets the Essential Requirements of all relevant European directives and is eligible for CE marking.
The CE Declaration of Conformity can be obtained from: www. The SCM's Advanced Functions are recommended only for those who are technically knowledgeable and familiar with audio electronics. The logic functions of the SCM expand the mixer's 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 Shure's Applications Group. The following logic functions are available for each channel:. Factory setting provides that when both Mute and Override are activated, Mute takes precedence see Internal Modifications for Override precedence. 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 at the DB multi-pin connector on the rear panel Figure The pin connections are given in the following table.
This section contains suggestions on the uses of the SCM's logic capabilities. Note that uses of these functions are not limited to the listed applications. The user is limited only by individual imagination and creativity. For additional suggestions and solutions to installation problems, contact Shure's Applications Group.
In the following paragraphs, the wiring diagrams refer to the DB connector pins shown in Figure 4. When a channel is muted, no audio is passed. The chairperson can, by activating a switch, silence all other microphones and be heard without interruption. When the chairperson's microphone activates, all other microphones mute.
Remote indicators can be used to indicate when a talker's microphone is on. To avoid switching clicks in the audio output, do not ground the power supply negative terminal in the audio system or rack ground. 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. The selected channels now function as they would in a non-automatic mixer see Figure Channels 1, 2 and 3 modified.
As described in the Operating Principles section, 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. The SCM can prevent these and similar sounds from activating microphones by taking the following steps.
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 as shown in Figure 17 Channels 1, 3 and 5 shown modified.
An existing sound system using volt relays can be used with the SCM without modification if the relay coil current draw is under mA. In normal operation, when several people talk, each microphone gates on so that no speech is missed. Once a microphone has gated on, other microphones cannot gate on until the talker has paused long enough for that microphone to gate off. Thus the person talking has the floor and cannot be interrupted.
Two or more control functions using the same logic pins can be isolated with diodes. In this manner a channel can be muted by an overall group mute switch, or by its own cough button see Figure Channels 1, 3 and 5 modified. Lancaster, Howard Sams Publishing Co. The SCM logic pins can interface with custom-designed digital control circuitry or microcomputers for unlimited possibilities of system control functions.
IMPORTANT SAFETY INSTRUCTIONS
Features include fast microphone selection, adjustable EQ, adjustable low-frequency roll off, and peak-responding output limiter. Features include adjustable EQ per channel, 48 V phantom power, active balanced microphone - or line-level inputs, line-level outputs, highly RF resistant chassis and circuitry, complete logic control of microphone activation, linking capacity for up to microphones, with an internal power supply. Detailed policy information regarding customer service numbers, service modifications, and replacement parts. A problem solver that increases speech clarity, reduces the risk of feedback and minimizes setup time. Non-automatic version of SCM features adjustable channel EQ and linking capability for up to 32 mics. Please enable your browser's JS to load this product's data.