Issue 1, June 2018
Model 371A User Guide
Page 6
Studio Technologies, Inc.
MODEL 371A
INTERCOM BELTPACK
corporate and government AV installations,
aerospace command and control, and
post-production facilities.
Dante Audio-over-Ethernet
Audio data is sent to and received from
the Model 371A using the Dante audio-
over-Ethernet media networking technol-
ogy. As a Dante-compliant device, the
Model 371A’s two audio output (Dante
transmitter) and two audio input (Dante
receiver) channels can be interconnected
(routed) with other devices using the Dante
Controller software application. The Dante
transmitter and receiver channels are lim-
ited to supporting four Dante flows, two
in each direction. The digital audio’s bit
depth is up to 24 with a sampling rate of
48 kHz. The Model 371A is AES67 compat-
ible and compliant with the Dante Domain
Manager™ software application.
Two bi-color LEDs provide an indication
of the Dante connection status. The Dante
Controller’s
Identify
command takes on a
unique role with the Model 371A. Not only
will it cause the talk and call button LEDs
to light in a unique highly visible sequence,
it can also be configured to turn off any
active talk channels.
Audio Quality
The Model 371A’s completely “pro”
performance is counter to the less-than-
stellar reputation of typical party-line (PL)
intercom audio. A low-noise, wide dynam-
ic-range microphone preamplifier and as-
sociated voltage-controlled-amplifier (VCA)
dynamics controller (compressor) ensures
that microphone audio quality is preserved
while minimizing the chance of signal
overload. DC power to support electret
microphones can be enabled if necessary.
The output of the microphone preamp and
compressor is routed to an analog-to-digi-
tal converter (ADC) section that supports
a sampling rate of 48 kHz with a bit depth
of up to 24. The audio signal, now in the
digital domain, travels through the proces-
sor and on to the Dante interface section
where it is packetized and prepared for
transport over Ethernet.
Audio input signals arrive via two Dante re-
ceiver channels. The supported sampling
rate is 48 kHz with a bit depth of up to 24.
The audio signals pass into the Model
371A’s processor where channel routing,
headphone level control, and sidetone
creation are performed within the digital
domain. Two push-in/push-out (“pop out”)
rotary controls make it easy to set and
maintain the desired headphone output
level. The audio signal destined for the
headphone output is sent to a high-per-
formance digital-to-analog converter and
then on to a robust driver circuit. A high
signal level can be provided to a variety of
headsets, headphones, and earpieces.
Call Function
A call function allows Model 371A users to
send and receive channel-specific visual
alert signals. Pressing the call pushbut-
ton on the top of the unit is all that’s re-
quired to signal other users that attention
is requested. Using 20 kHz tones, the call
signals are sent within the audio chan-
nels (“in band”) allowing interoperability
between multiple Model 371A units as well
as being compatible with legacy party-line
intercom systems. The call function can
be useful to indicate to users that they are
needed “on headset” or should be actively
listening to an intercom channel. The call
function can also be used to provide real-
time cues to production personnel during
the running of live events.
