Studio Technologies 41 2013 - Manual (Page 6)

Issue 3, November 2013 Model 41 User Guide
Page 6 Studio Technologies, Inc.
IFB outputs provide an effective means of
delivering power and two channels of audio
to user devices by means of standard au-
dio cables. These cables, ubiquitous to the
audio industry, interface using 3-pin male
and female XLR connectors. Using IFB
outputs and standard audio cables it’s a
simple matter to support user devices such
as listen-only beltpacks and announcer’s
consoles with no external power source
required. Whether the IFB source and user
devices are 100 or 1000 feet apart, reliable
operation can almost always be provided.
In many cases, the Model 41 Interface will
be used in on-air television applications.
Whether installed in a fixed location or
as part of a mobile facility, the unit is ca-
pable of providing excellent performance.
In addition, the Model 41 can be used for
non-broadcast applications. For example,
audio recording and post-production fa-
cilities can also effectively use the Model
41. Combined with stereo or mono listen-
only beltpacks, also available from Studio
Technologies, a variety of headphone cue
systems can easily be deployed. And since
the Model 41’s audio inputs are compatible
with standard line-level audio signals virtu-
ally any analog source can be connected.
Four Independent IFB Outputs
The Model 41 supplies four independent
IFB outputs. Each circuit consists of two
audio inputs and a 2-channel “wet” IFB
output. The audio inputs are transformer
coupled, have a nominal level of +4 dBu,
and are compatible with balanced or unbal-
anced sources. In on-air television broad-
cast applications the audio sources will
often be analog outputs from matrix inter-
com systems. Two sources are typically
designated to serve as a 2-channel user
cue signal. Generally one source is
configured in the matrix intercom system
as “interrupt” while the other is configured
as “program.” An alternate term often used
for the “interrupt” channel is “program-
with-interrupt.” This may be more descrip-
tive as the function is actually a program
source that gets interrupted with talkback
audio. The “program” channel is typically a
continuous source of program audio.
An alternate term is “program-only.”
For other applications, the Model 41’s
audio inputs can be connected to a
2-channel or stereo audio source. This
configuration may prove useful in radio
broadcasting, audio-with-picture, or re-
cording studio applications. The specific
application will dictate whether both cue
signals will be utilized by the end user.
In on-air sports broadcast situations a
“double-muff” (stereo) headset will provide
a user with both audio channels, one for
each ear. In interview or news-gathering
applications it’s common to use a single
“earpiece” to provide a user with only
program-with-interrupt audio.
Maintaining excellent audio performance
was a major Model 41 design goal—the
hiss, hum, and noise associated with typi-
cal IFB outputs was simply not acceptable.
The Model 41 meets those requirements
with audio that is “on-air” quality: low
distortion, high signal-to-noise ratio, and
ample headroom. On-air talent and guests,
production personnel, and technicians will
all appreciate the clean, quiet cue signals.
The Model 41’s IFB outputs provide power
and two channels of unbalanced audio
over a single 3-conductor output. The
output power is 30 volts DC with a maxi-
mum current of 220 milliamperes. A major
strength of the Model 41 is the IFB output’s
ability to effectively deliver DC power over