Lectrosonics UM190 - Manual (Page 7)

OPERATING INSTRUCTIONS
1) Install a fresh battery according to the instructions on the previous page.
2) Insert the microphone plug into the input jack, aligning the pins; be sure that the connector locks in.
3) Attach the antenna to the jack on the bottom of the unit. Be sure it is screwed in firmly.
If you have used our VHF transmitters before, you will notice that they use the
shield of the microphone cord as the antenna. The UM190 UHF transmitter
uses a separate 1/4 wave flexible wire as the antenna. If the antenna is not
attached, the transmitter will not radiate.
3) Turn the power switch to the "MUTE" position on the transmitter.
4) Position the microphone in the location you will use in actual operation.
5) While speaking or singing at the same voice level that will be actually used, observe the MOD LEVEL
LEDs. Adjust the MIC LEVEL control knob until the LEDs begin to light. Start at a low setting where
neither LED lights as you speak. Gradually, turn the gain up until one LED lights, then the other.
The LEVEL LED lights when the audio level is about 12dB below full modulation. The LIMIT LED lights
when the limiter begins to operate. There is over 40dB of limiting range without overload above the LIMIT
LED, so it is normal that the LIMIT LED light up 5% to 10% of the time during use.
6) Once the gain has been adjusted, the transmitter audio can be turned on to make sound system level
adjustments. Move the power switch from the MUTE to the ON position and adjust the receiver and/or
sound system level as required.
OPERATING NOTES
The MIC LEVEL control knob should not be used to control the volume of your sound system or recorder levels.
This gain adjustment matches the transmitter gain with the user’s voice level and microphone positioning.
If the mic level is too high -- both LEDs will light frequently or stay lit. This condition may reduce the dynamic
range of the audio signal.
If the mic level is too low -- neither LED will light, or the LEVEL LED will light dimly. This condition may cause hiss
and noise in the audio.
The first LED turns on 12dB below full deviation. The limiting LED turns on at full deviation and indicates that the
input shunt compressor is operating. The input limiter will handle peaks over 40dB above full modulation,
regardless of the gain control setting. The limiter uses a true absolute value circuit to detect both positive and
negative peaks. The attack time is 5 milliseconds and the release time is 200 milliseconds. Occasional limiting is
desirable, indicating that the gain is correctly set and the transmitter is fully modulated for optimum signal to noise
ratio.
Different voices will usually require different settings of the MIC LEVEL control, so check this adjustment as each
new person uses the system. If several different people will be using the transmitter and there is not time to make
the adjustment for each individual, adjust it for the loudest voice.
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