ETS VBF-4 User manual

VBF-4 Microphone Bandpass
Filter / Interface Instructions
The VBF-4 is a 4 channel channel voice bandpass filter / interface for use with all SM1 series
microphones. The VBF-4 is useful installed in environments with high levels of background noise. VBF-4
features a convenient way of supplying power to the SM1s and installer friendly termination of the cable
runs. The VBF-4 is typically connected to recording equipment such as DVRs, IP cameras, etc. Note the
audio output signals of the VBF-4 are line level (0dbm).
SM1 Microphone Placement
Locate the SM1 microphone in the center of the space to be monitored. If a large area 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. The SM1 should be placed as close as possible to the subject(s) to be
monitored. The SM1 is usable at distances of up to 25 feet but is dependent on the level of background
noise in the area. Experimentation in the environment will determine what distances work best.
VBF-4 location and power
The VBF-4 interface box is designed to be located next to a DVR or IP camera. The VBF-4 requires a
120VAC power source within 3 feet of its location. If this is not possible in your application, you can splice
in up to 100 feet of 22 awg, 2 conductor cable to extend the distance between the AC power source and
the VBF-4.
Cable Run
Run a 22 gauge, stranded, two conductor shielded cables between the VBF-4 interface and the SM1
microphones. Keep the cable run distance at or under 1,000 feet and away from AC power sources, light
fixtures and electrical equipment. See Figure 1 for connection diagram.
Adjusting the SM1 gains and VBF-4 level controls
If the VBF-4 will be plugged into a “microphone level” input of an IP camera, set the SM1 gains slightly
clockwise (or 1/8 of a full turn) from full counter-clockwise. Then use the “level controls” on the VBF-4 to
set the volume of each microphone to produce an acceptable audio level at the head end.
If the VBF-4 will be used with a “line level” inputs, turn the gain controls of the SM1s to 3/4 full clockwise
and adjust the level controls on the VBF-4 to produce the clearest audio levels at the head end.
SM1 filters
Switch both LC and HC filters of the SM1s to the ‘in’ positions to further enhance the voice band pass of
the VBF-4.

Figure 1.
Caution
It may be against the law to install this microphone kit in certain environments. It may also be against the
law to record conversations of the person(s) being monitored without their knowledge. It is the
responsibility of the installation company and end-user to determine if the application of this product is
legal. These laws vary from state to state. If you are not informed on these matters, consult a qualified
attorney or contact the appropriate state agency. A sticker is provided with this kit for the applications
where notification must be posted.
Warranty
All ETS products carry a one year parts and labor warranty. This warranty does not cover damages as a
result of misuse, improper handling of the unit or exposure to extreme temperatures or moisture. At its
discretion, ETS reserves the right to repair or replace this unit under the conditions of the warranty. If you
experience problems with your equipment call ETS at: 505-888-3923 to obtain a return authorization
number. Equipment requiring repair beyond the warranty period or units that have been damaged or are
not covered under the warranty can be repaired by ETS for a minimal cost under most conditions.
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