SM9 Microphone Kit Instructions
The SM9 Microphone Kit is a complete stand-alone audio monitoring system that supports up to 8
microphone inputs. Microphones can be switched into the mix at different levels via the front controls. The
SM8 can be used in conjunction with a CCTV system. The SM8 easily connects to recording equipment
such as linear time-lapse VCRs and audio tape recorders.
Microphone Placement.
Place the SM1 microphones in the areas of interest in a room or multiple rooms to be monitored. If an
entire room is to be monitored, locate the SM1 in the middle of the room. Do not mount the microphone
near air conditioning vents, light fixtures or electrical equipment. Point the SM1 in the direction of the area
to be monitored. The SM1 should be placed at least 4 feet away from the subject(s) to be monitored.
Place the SM8 switcher/mixer in the room from which you will be monitoring. The SM1 is still useable in
the range of 15-25 feet but is dependent on the level of background noise in the area. Experimentation in
the environment will determine what distances work best.
Cable Run
Run a 22 gauge, stranded, two conductor shielded cable between the SM8 amplifier and the SM1
microphone. Keep the cable run distance under 1,000 feet and away from AC power sources, light
fixtures and electrical equipment.
See Figure 1 for connection diagram.
Microphone Mounting
The SM1 can be surface or flush mounted on ceilings or walls. For flush mounting, cut a 2 ¼” by 2
¾
“
hole in the wall or ceiling tile to allow room for the circuit board, connect the cable and mount the SM1 to
the surface with screws. For surface mounting, purchase a low profile Wire Mold single gang box and
mount it to the wall or ceiling with screws, connect the cable and attach the SM1 to the box.
Adjusting the SM1 Gain
Start with a midrange setting of the gain control on the SM1. Adjust the c or – for maximum clarity.
If the sound at the amplifier is distorted, rotate the control towards the – mark (counter- clockwise). If the
volume at the amplifier is too low, rotate the control towards the + mark (clockwise).
Setting the SM1 Jumpers
The SM1 microphone has jumper selectable treble boost and limiter circuits. The treble boost circuit when
jumpered in, emphasizes the high frequency sounds that the microphone picks up. This is useful for
improving the sound quality on slow speed tape recordings (VCR time-lapse recordings). The limiter
circuit, when jumpered in, automatically keeps the SM1’s output at a relatively constant level. This
eliminates the need for the listener to reduce the volume control on the amplifier when sounds get louder.
Note: Do not use the SM1’s limiter circuit if you are using a tape recorder or other device that uses
an AGC or limiter circuit. Most tape recorders have limiter circuits.
The recommended jumper settings are as follows:
Stand-alone Application
Tape Recorder Application
Limiter “IN”
“OUT”
Treble Boost
“OUT”
“IN”
