Lectrosonics SMDa, Instruction Manual, Page: 10 / 24

SMDa Series
Setting Transmitter
Operating Frequency
Frequency displayed
The Operating Frequency of the
in MHz
SMDa can be displayed either
in MHz or as a two-digit hexa­
decimal number. (See Controls
and Functions, FREQ Button .)
Frequency displayed as
The SM’s operating frequency
two-digit hexadecimal
can be set with the unit in
number
Standby Mode or powered up
for normal operation. Use the following procedure to
change the Operating Frequency of the SM transmitter:
1) If the LCD is displaying something other than the
Frequency Screen, press the FREQ button on the
SM Control Panel to enter this screen.
Note: The default display is in MHz. Pressing
the FREQ button again displays the operating
frequency as a two-digit hexadecimal number
that corresponds the equivalent Lectrosonics
Frequency Switch Setting.
2) While holding the FREQ button, use the Up or
Down arrow buttons to move the operating fre­
quency up or down in 100 kHz increments from the
current setting.
Note: The operating frequency displayed on the
LCD wraps as it reaches the upper or lower end of
its range. Thus, if you intend to move the operating
frequency from the lower end of the range to the
upper end, it may be faster to do this by using the
Down arrow until the frequency wraps to the upper
end.
Most Lectrosonics receivers indicate the operating
frequency both in MHz and as a two digit hexa­
decimal number. This conforms to the Lectrosonics
tradition of setting the operating frequency using
two 16-position rotary switches. The SMDa Series
units offer the ability to set the operating frequency
in a similar manner. Pressing the FREQ button
while the LCD displays the operating frequency in
MHz will change the display to show the equivalent
two-digit hexadecimal frequency select switch set­
ting. Simply use the UP or DOWN arrow to increase
or decrease the operating frequency.
Adjusting the Low Frequency Roll-off
Repeatedly press the AUDIO button until the LF roll-
off adjustment screen appears. Then press and hold
the AUDIO button while selecting the desired roll-off
frequency with the UP and DOWN arrows.
Attaching a Microphone and Adjusting Gain
The control panel Modulation LEDs indicate the modu­
lation level and limiter activity. Once set, the transmit­
ter’s audio level setting
should not
be used to control
the volume of your sound system or recorder levels.
This gain adjustment matches the transmitter gain with
the microphone’s output level, the user’s voice level and
the position of the microphone. The audio input level
can be set with the unit in Standby Mode or while pow­
ered up in normal operation.
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 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.
1) With the transmitter powered off, insert the micro­
phone plug into the Audio Input Jack, aligning the
pins and ensuring that the connector locks.
See the following page for suggestions on using
the microphone connector and sleeve
2) Place the transmitter in Standby Mode, or if the unit
is to be powered up and adjusted, mute the main
sound system prior to powering up the transmitter.
3) Position the microphone in the location where it will
be used in actual operation.
4) Observe the audio level LEDs while speaking or
singing into the microphone at the same voice level
that will be used during the program. While holding
the AUDIO button, press the UP or DOWN arrow
buttons until the both the -20 and -10 LEDs glow
green, with the -20 LED occasionally flickering red.
This will maximize the signal to noise ratio of the
system with full modulation and provide subtle limit­
ing to prevent overload and audible compression of
signal peaks.
Note: Setting the audio level too high reduces the
dynamic range of the audio signal. Setting the
audio level too low may cause hiss and noise in
the audio.
5) If the unit was set up in Standby Mode, it will be
necessary to turn the transmitter off, then power it
up again in normal operation so the RF output will
be on. Then the other components in the sound or
recording system can be adjusted.
The roll-off frequency can be set to 35, 50, 70, 100, 120
and 150 Hz.
LECTROSONICS, INC.
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