Issue 3, December 2021 Model 391 User Guide
Page 6 Studio Technologies, Inc.
Applications
The most-typical application for the Model
391 is to alert users that a call signal on an
intercom channel is active. Some techni-
cians and engineers associated with the-
ater, entertainment, and corporate events
won’t always stay “on headset” and may
need to be alerted when their presence
on the production’s intercom system is
needed. As an example, a front-of-house
audio mixer could nd value by placing a
Model 391 unit on their audio console or
associated equipment rack. They would
then be able to quickly respond to an
intercom call request while not having to
continuously wear a headset that would
interfere with their normal work.
The Model 391 can also be used as a
general-purpose status indicator for var-
ious live-event applications. Instead of
responding to intercom call signals, the
STcontroller application can be used to
select the real-time action of the visual
indicator, audio sounder, and line output.
For example, a Model 391 placed in a
theater’s “green room” could provide a
visual “quiet on the set” indication.
This might be useful to provide an on-air
or program audio feed to inputs on vari-
ous pieces of audio equipment. The line
output can also be congured to be active
only when a call signal is present. This
could serve as a paging output or allow
an audio call function to be implemented.
In addition to responding to intercom
beltpack call requests, the Model 391 can
also be used in many other applications.
These include allowing one of the contact
closure inputs on a Studio Technologies’
Model 44D Interface to trigger the alerting
functions on a Model 391. Being Dante
networked audio devices, the units will
function together as long as they are
located on same network, whether the
devices are in the same room or on the
opposite sides of a university campus.
The Model 391’s analog line output offers
a unique resource. It can be congured as
an always-active output that follows one
of the audio inputs associated with the
Model 391. Additionally, signals generated
by other products, such as the Studio Tech-
nologies’ Models 214 and 215 Announcer’s
Consoles, will allow the Model 391 to serve
as a broadcast “on-air” indicator.
Features
For visual alerting the Model 391 incorpo-
rates a trapezoidal-prism-shaped polycar-
bonate lens with multiple red/green/blue
(RGB) LEDs. The unit is typically placed
on an audio console, lighting board, or on
top of an equipment rack. The visual indi-
cator provides a highly visible 360-degree
viewing eld. Conguration choices allow
selection of the exact color, intensity, and
lighting cadence. Another selection deter-
mines what action will cause the LEDs to
activate. It can respond to a call signal or
can remain enabled as a status indication.
This allows the Model 391 to be used in
a variety of alerting applications, ranging
from a request to join an intercom conver-
sation to providing a “rehearsal in prog-
ress” or “closed set” indication.
A conguration choice allows call signals
to be simultaneously detected on audio
input channels 1 and 2. Unique colors will
be displayed in response to a call signal on
channel 1 versus a call signal on channel 2.
The Model 391 includes an audio sounder
whose output will “cut through” ambient
audio to gain the attention of nearby per-
sonnel. The character of the sounder was
