Lectrosonics UM195b User Manual download pdf (Page 7)

UHF Belt-Pack Transmitter

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 control panel of the unit. Be sure it is screwed in securely.

3) Turn the power switch to the “ON.”

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 AUDIO LEVEL LEDs.

Adjust the AUDIO 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 “-20” LED lights when the audio level is about 20dB below full modulation. The “0dB” LED lights when the

limiter begins to operate. There is over 30dB of limiting range without overload above the “0dB” LED, so it is

normal and desireable that the “0dB” 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.

OPERATING NOTES

The AUDIO 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 “-20” LED will light dimly. This condition may cause hiss and

noise in the audio.

The first LED turns on 20dB 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 30dB 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 AUDIO 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.

Rio Rancho, NM – USA

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Lectrosonics UM195b User Manual Page 7