
SM17 Microphone Switcher/Mixer Kit Instructions
The SM17 Kit is a complete stand-alone audio monitoring system that includes 16 microphone inputs.
Microphones can be switched into the mix at different levels via the front controls. The SM16 can be used in
conjunction with a CCTV system. The SM16 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, place 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 four feet away from the subject(s) to be monitored. Place the SM16 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 SM16 amplifier and the SM1 microphone.
Keep the cable run distance under 500 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.
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-along Application Tape Recorder Application
Limiter “IN” “OUT”
Treble Boost “OUT” “IN”
Using the SM16 with an audio recorder or VCR
If you are using an audio recorder, press and hold down Button Number 2 (approximately 2 seconds) until the
Recorder light comes on; then connect the VCR as shown in the drawing on the reverse side.
Note: If the SM16 is not going to be used with an audio recorder, press and hold down Button Number 2
until the Recorder light goes off.
Changing SM16 Modes: Switcher Mode or Mixer Mode
The SM16 can be set to operate as a 1-of-16 channel switcher or as an 16 channel mixer. In the 1-of-16 mode,
only one channel can be monitored at a time. Press any button to change channels. In the mixer mode, any
combination of microphones can be mixed together. Press an unlit channel to select and press a lit channel to
unselect.
To change modes, press down and hold Button 1 until the mixer light changes state. The SM16 will remember
your settings for each mode and restore that setting when you change modes. Mixer Mode is on when the Mixer
Mode light is on, and Switcher is on when the Mixer Mode light is off.