Lectrosonics MM400c - Manual (Page 12)

MM400C
LECTROSONICS, INC. 12
POWER
LED
Modulation
LEDs
Power On/Off
Switch
NOTE: All 400 Series (and a number of earlier
receivers) offer a front panel LCDs that indicate the
correct transmitter switch settings when locating
clear channels. Use the scanning functions on
these receivers to find a clear channel, then switch
both the receiver and transmitter to the Frequency
Select Switch settings indicated in the receiver’s
display.
If you are using a 100 Series receiver, turn off the trans-
mitter and observe the RF LED on the front panel of the
UCR100 receiver. If it flickers, or glows red, then adjust
the UCR100’s Frequency Select Switches up or down in
100 kHz increments until the RF LED extinguishes. Set
the MM400C transmitter’s Frequency Select Switches
to the same settings. Turn on the transmitter and ob-
serve that the RF LED on the receiver glows brightly.
Attaching a Microphone and
Adjusting Audio Levels
The front panel Modulation LEDs indicate limiter activity.
(See chart.) Since the distortion introduced by the lim-
iter is minimal and full modulation is assured, occasional
forays into the red by the -10 LED is acceptable.
1) Install a fresh battery.
2) Insert the watertight microphone plug into the Mic
Jack and screw it in snugly.
WARNING: Do not overtighten as this will
distort the “O-ring” and allow moisture to enter
the unit.
3) Mute the main sound system and rotate the Audio
Level Control on the MM400C to maximum counter-
clockwise (Off).
4) Set the Power ON/OFF switch to the ON position.
5) Position the microphone in the location where it will
be used during in actual operation.
6) Observe the MM400C Modulation LEDS while
speaking or singing into the microphone at
the same voice level that will be used during
the program. Gradually rotate the Audio Level
Control control clockwise until both LEDs glow
green with the -20 dB occasional blinking
red. This indicates full modulation and is the
optimum setting for the transmitter’s gain.
Signal Level -20 LED -10 LED
Less than -20 dB Off Off
-20 dB to -10 dB Green Off
-10 dB to +0 dB Green Green
+0 dB to +10 dB Red Green
Greater than +10 db Red Red
NOTE: 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.
7) Once the MM400C’s audio gain has been set, the
remaining components of the audio system can be
energized and adjusted.
WARNING: The AUDIO LEVEL control 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.
Microphone Jack
Audio
Level
Control