ETS SM1-BM Instructions

SM1-BM Microphone Instructions
The SM1-BM is a high quality, 12-24VDC powered, back mounted, omni-directional, pre-amplified
microphone for use with DRVs, IP cameras, etc. Note- the audio output of the SM1-BM is switch
selectable "line level" (0db) or "microphone level" (-30db).

SM1-BM Microphone Placement.

not mount the microphone near air conditioning vents, light fixtures or electrical equipment. The
SM1-BM should be placed as close as possible to the subject(s) to be monitored. The SM1-BM is
useable 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.

Cable Run

Run a 22 gauge, stranded, two conductor shielded cable between the SM1-BM microphone and
the monitoring device. Keep the cable run distance under 1,000 feet and away from AC power
sources, light fixtures and electrical equipment. Connect power to the + terminal, the audio signal
to the "audio" terminal and ground to the – terminal. The Ground of the power and audio signal
must share a common ground for proper operation. See Figure 1 for connection diagram.

Mounting

The SM1-BM is designed to mounted behind a thin flat surface such as a Kios terminal panel.
Drill a ¼" inch hole in the surface and attach the SM1-BM to the inside surface of the panel;
Clean the surface well with alcohol and after it dries, Pess the SM1-BM firmly onto the surface.

Adjusting the SM1-BM Gain

The SM1-BM output level is set by selecting the desired volume range and adjusting the gain
control.
The "Volume Range" switch should be set to the "LO" position when using the SM1-BM with IP
cameras that utilize "microphone inputs" also known as "Mic. Level" inputs. The switch should be
placed in the "HI" position when using IP cameras with "Line level" inputs of DVRs and IP
cameras.
The SM1-BM is shipped with the gain set at midrange. If the sound at the "head end" is distorted,
rotate the control towards the – mark (counter-clockwise). If the volume at the "head end" is too
low, rotate the control towards the + mark (clockwise).

Setting the SM1-BM Hi-Cut/Lo-Cut switches

The normal frequency response of the SM1-BM microphone is 500-16Khz. When both switched
"in", The "HI Cut" and "Lo Cut" filters set the SM1-BM's frequency response to 900-6Khz.
Enabling one or both of the filters is useful when background noise needs to be further reduced
and intelligibility of speech emphasized. We recommend experimenting with the switch settings to
achieve the best result for your application.