User Guide

Model 374A User Guide Issue 4, February 2021
Studio Technologies, Inc. Page 11
MODEL 374A
INTERCOM BELTPACK
Microphone Input – Electret Power
Choices are Enabled or Disabled.
If the headset has an electret microphone
that requires a source of low-voltage DC
power for operation enable the Electret
Power check box. If the associated head-
set has a dynamic (non-powered) micro-
phone do not enable the Electret Power
check box. Most broadcast headsets that
terminate on a 5-pin male XLR connector
will not require microphone power. The
on/off status is displayed by way of a red
LED, labeled MIC POWER, that is located
adjacent to the headset connector.
Note that the Model 374A cannot supply
P12 or P48 phantom power that may be
required for balanced condenser (capaci-
tor) microphones. This should not pose an
issue as this type of microphone is essen-
tially never associated with a headset that
would be used for intercom applications.
Microphone Input – Gain
Choices are 22 dB, 30 dB, 42 dB, and
48 dB.
Dynamic microphones have an output
level that is typically lower than that pro-
vided by electret microphones. As such,
the 42 or 48 dB gain settings will probably
be appropriate for them. Electret micro-
phones often have internal circuitry which
provides a relatively high output level. The
22 and 30 dB gain settings will typically be
appropriate with this type of microphone.
When a dynamic microphone is con-
nected to the Model 374A the 42 dB gain
setting may be correct for many applica-
tions. Setting the gain for 48 dB may be
helpful in some applications, such as with
headsets that have a low microphone out-
put level. The 48 dB gain setting may also
be useful when the Model 374A is going
to be deployed at events where users are
not able to speak at normal levels, e.g.,
sporting events such as golf tournaments
where “whispering” may be necessary.
Electret microphones typically have a
higher output level due to their internal
preamplifier circuitry. As such, less pream-
plifier gain may be required. Selecting the
22 or 30 dB gain setting will probably be
appropriate in these cases.
The compressor active LED, labeled
COMP and visible adjacent to the headset
connector, can act as a guide when set-
ting the microphone preamplifier gain.
During normal talk operation the com-
pressor active LED should light intermit-
tently. If, for example, with a dynamic
microphone the LED rarely lights and the
preamp gain is set to 42 dB it might be a
good idea to change it to 48 dB. If the LED
is lit fully during normal talking in a situ-
ation where the headset has an electret
microphone and the gain is set for 30 dB,
changing it to 22 dB might be warranted.
Headphone Output Channel Routing
Choices are Left, Right, and Left and Right.
Four audio input sources (Dante receiver
channels) can be assigned to the head-
phone output channels using the Dante
Controller application. How these four
audio signals are routed to the Model
374A’s headphone output channels can
be configured using this configuration
choice. The three options provide flexibility
in how the audio sources are presented
to the user. When using a stereo (“double
muff”) headset it’s common for the audio
input sources to be routed to both the
left and right channels. But the Model
374A’s flexibility allows each source to be
independently configured for sending to