Manual
Issue 2, August 2019 Model 370A User Guide
Page 6 Studio Technologies, Inc.
MODEL 370A
INTERCOM BELTPACK
Dante Audio-over-Ethernet
Audio data is sent to and received from the
Model 370A using the Dante audio-over-
Ethernet media networking technology.
As a Dante-compliant device, the Model
370A’s two audio output (Dante transmitter)
and two audio input (Dante receiver) chan-
nels can be interconnected (routed) with
other devices using the Dante Controller
software application. The Dante transmit-
ter and receiver channels are limited 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 370A is AES67 compatible and com-
pliant 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 370A. 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 370A’s completely “pro” per-
formance is counter to the less-than-stellar
reputation of typical party-line (PL) intercom
audio. A low-noise, wide dynamic-range
microphone preamplifier and associated
voltage-controlled-amplifier (VCA) dynam-
ics controller (compressor) ensures that
microphone audio quality is preserved
while minimizing the chance of signal over-
load. DC power to support electret micro-
phones can be enabled if necessary.
The output of the microphone preamp
and compressor is routed to an analog-to-
digital converter (ADC) section that sup-
ports 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
processor and on to the Dante interface
section where it is packetized and pre-
pared 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
370A’s processor where channel routing,
headphone level control, and sidetone
creation are performed within the digital
domain. This provides flexibility, allowing
precise control of the audio signals and
eliminating the need for the two rotary lev-
el controls from having to directly handle
analog audio signals. The audio signals
destined for the 2-channel headphone out-
put are sent to a high-performance digital-
to-analog converter and then on to robust
driver circuitry. High signal levels can be
provided to a variety of headsets, head-
phones, and earpieces.
Call Function
A call function allows Model 370A users
to send and receive channel-specific vi-
sual alert signals. Pressing the call push-
button on the top of the unit is all that’s
required to signal other users that atten-
tion is requested. Using 20 kHz tones, the
call signals are sent within the audio chan-
nels (“in band”) allowing interoperability
between multiple Model 370A units as well
as being compatible with legacy party-
line intercom systems. Call signals 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.