Studio Technologies 44D User manual
Copyright © 2017 by Studio Technologies, Inc., all rights reserved
www.studio-tech.com
50032-1117, Issue 2
User Guide
Issue 2, November 2017
This User Guide is applicable for serial numbers
M44D-01151 and later with application firmware 2.1 and later
and Dante firmware 2.0.0 (Ultimo 3.10.1.12) and later
Also applicable to units with serial numbers
M44D-00151 to 00250; see Appendix A for details
Model 44D
Audio Interface
Dante® to and from Analog Audio
This page intentionally left blank.
Model 44D User Guide Issue 2, November 2017
Studio Technologies, Inc. Page 3
Table of Contents
Revision History ............................................................ 4
Introduction ................................................................... 5
Getting Started .............................................................. 9
Configuration ................................................................ 14
Operation ...................................................................... 17
Technical Notes ............................................................. 21
Specifications ................................................................ 25
Appendix A: Original vs Updated Model 44D .............. 27
Issue 2, November 2017 Model 44D User Guide
Page 4 Studio Technologies, Inc.
Revision History
Issue 2, November 2017:
1. Documents addition of operating mode configuration (audio interface and tone
generator).
Issue 1, September 2016:
1. Initial release.
Model 44D User Guide Issue 2, November 2017
Studio Technologies, Inc. Page 5
Introduction
The Model 44D Audio Interface provides
a simple yet high-performance means of
interfacing two channels of analog line-level
audio to and from applications that utilize
Dante® audio-over-Ethernet media net-
working technology. Two Model 44D units
can also provide one-to-one signal paths,
two in each direction, over a standard lo-
cal area network (LAN). In addition, the
unit supports transport of status signals or
contact closures between Model 44D units
and other compatible products. There are
two general-purpose inputs (GPI) and two
general-purpose output (GPO) on each
Model 44D.
A special operating mode allows the Model
44D to serve as a tone generator rather
than an audio interface. When configured
for the tone generator mode 1 kHz and 18
kHz sine-wave audio signals are available
in both the analog and digital domains.
The Model 44D is a fully professional prod-
uct that offers the audio quality, features,
and reliability required by 24-hour, on-air,
and commercial applications. The two
line-level audio inputs use standard 3-pin
female XLR connectors for easy interfac-
ing with balanced and unbalanced sourc-
es. The input audio signals are converted
to 24-bit digital and then transported via
the Dante interface. Two digital audio
signals arrive into the Model 44D via the
Dante interface and are then converted to
analog. Two 3-pin male XLR connectors
on the Model 44D’s back panel provide
balanced line-level outputs.
The Model 44D is designed as a bridge,
using Dante to link analog or other Dante
interfaces found on devices such as matrix
intercom systems, broadcast routers, and
audio consoles. An Ethernet connection
is all that’s required to make the Model
44D part of a sophisticated, networked
audio system. Dante audio-over-Ethernet
has found wide acceptance as an audio
“backbone” due to its ease of use, high
performance, strong interoperability, and
wide adoption by a large number of equip-
ment manufacturers. The Model 44D is a
Figure 1. Model 44D standard “throw-down” front view
Figure 2. Model 44D back view
Issue 2, November 2017 Model 44D User Guide
Page 6 Studio Technologies, Inc.
general-purpose “tool” that helps to ex-
pand Dante’s capabilities to facilities and
equipment that primarily supports signals
in the analog domain.
Careful attention to circuit design and
component selection ensures that excel-
lent audio quality is maintained. Extensive
filtering helps prevent damage or less-
than-optimal performance should DC
voltage, ESD (“static”), or strong RF sig-
nals be present on the associated analog
signals.
Configuration switches allow several
Model 44D operating parameters to be
selected. The nominal audio levels of the
line input and line output functions can
be independently selected. In this way
compatibility with SMPTE® and EBU
nominal signal levels is supported. Audio
level meters provide confirmation of sys-
tem performance during setup and opera-
tion. Two general purpose input and two
general purpose output functions allow
support for installer-selected applications,
including party-line intercom call-light
functions. Two LEDs provide a direct indi-
cation of the status of the GPO functions.
The Model 44D can be powered by Power-
over-Ethernet (PoE) or an external source
of 12 volts DC. Standard connectors
are used for the line inputs and outputs,
Ethernet, GPI/GPO, and DC power in-
terconnections. The Model 44D’s enclo-
sure has a “1/2-rack” 1U form factor and
weighs less than two pounds, making it
well suited for use in portable applications.
Alternately, using one of the optional rack-
mount front panels, one or two Model 44D
units can be mounted in a single space
(1U) of a standard 19-inch rack enclosure.
Dante Audio-over-Ethernet
Audio data is sent to the Model 44D us-
ing the Dante audio-over-Ethernet media
networking technology. Audio signals
with a sample rate of 44.1 or 48 kHz and
a bit depth of up to 24 are supported. The
two line input channels are converted to
digital and then routed to transmitter (out-
put) channels on the Dante interface. Two
transmitter (output) channels from an as-
sociated Dante-enabled source device can
be assigned to the Model 44D’s receiver
(input) channels using the Dante Controller
application. These are then converted into
analog outputs.
Applications
The most basic application for Model 44D
is for transporting analog audio signals to
and from one location to another using
the data transport resources of a local area
network — there’s really no simper means
to getting high-quality audio from “point A
to point B” and back. With standard con-
nectors and PoE power, setup can be com-
pleted in just a few minutes. This makes
Model 44D units effective in both fixed and
portable applications.
The Model 44D can also find use when an
application already supports Dante. For
example, ports on a matrix intercom system
that directly supports Dante, such as the
RTS ADAM® with OMNEO®, can be routed
to a Model 44D’s Dante output (transmitter)
and input (receiver) channels. The Model
44D will then provide two analog input and
two analog output interfaces for use in a
variety of applications. These can include
interfacing with audio inputs and outputs as-
sociated with audio consoles, providing tal-
ent cueing (IFB) feeds, and interfacing with
the audio outputs of aerial camera systems.
Model 44D User Guide Issue 2, November 2017
Studio Technologies, Inc. Page 7
The Model 44D’s tone generator mode
enables the unit to create 1 kHz and 18 kHz
analog and digital sine-wave audio signals.
These are provided as a resource when
supporting remote-production (REMI) ap-
plications that use the Studio Technologies
Model 5422 Dante Intercom Audio Engine.
The tones, specifically 18 kHz, can be used
by a matrix intercom system to facilitate
creation of voice-with-tone interruptible
foldback (IFB) signals. When routed to the
Model 5422’s interrupt inputs these special-
ized IFB signals will allow excellent talent
cueing performance to occur.
Line Inputs
The Model 44D provides two analog line-
level input channels. A configuration choice
allows the nominal level of the input signals
to be +4 or 0 dBu. When configured for
+4 dBu the unit will be compatible with
SMPTE applications where the nominal
digital signal level is –20 dBFS. In the 0 dBu
configuration the line inputs are optimized
for EBU applications where the nominal
digital signal level is –18 dBFS.
The electronically balanced (differential)
input circuits are capacitor-coupled and
ESD (static) protected for reliable operation
in a variety of applications. They are also
protected from damage should a moder-
ate DC voltage be accidentally connected.
Sources can include analog I/O cards on
matrix intercom systems, audio consoles,
wireless microphone receivers, and broad-
cast routers.
Line Outputs
The Model 44D provides two analog line-
level output channels. As with the line
inputs, a configuration choice allows the
nominal level of the output signals to be
+4 or 0 dBu. This allows compatibility in
applications where SMPTE (+4 dBu =
–20 dBFS) or EBU (0 dBu = –18 dBFS)
standards may apply. The outputs are
electronically balanced, capacitor-coupled
and ESD (static) protected. The outputs
are compatible with virtually all balanced
and unbalanced inputs with an impedance
of 2 k ohms or greater.
General Purpose Inputs and
Outputs
The Model 44D allows the sending and
receiving of status signals using high-
frequency audio tones that are included
with within the Dante audio channels.
When two Model 44D units are intercon-
nected using an Ethernet network and
Dante, two status signals will be trans-
ported in each direction. Each general
purpose input (GPI) is compatible with
contact closures provided by equipment
such as matrix intercom systems or rout-
ers. A closure on a GPI on one Model 44D
unit will result in the closing (shorting) of
a solid-state relay contact on the other
Model 44D. To assist in implementing
specialized GPI and GPO applications a
source of low-current DC power is also
provided.
The GPI and GPO functions can be espe-
cially useful in party-line intercom applica-
tions where call-light signals are utilized.
Contact closures on matrix intercom
systems can be “repeated” by Model 44D
units that are located anywhere within the
associated local area network (LAN). The
Model 44D is also directly compatible with
the call-light signal support provided by
the Studio Technologies’ Model 45DC and
Model 45DR Intercom Interface units. With
a Model 44D appropriately interconnected
Issue 2, November 2017 Model 44D User Guide
Page 8 Studio Technologies, Inc.
with a matrix intercom system full call-light
support can be provided to and from RTS®
and Clear-Com® party-line intercom cir-
cuits.
Pro Audio Quality
The Model 44D’s audio circuitry was de-
signed in the spirit of professional audio
equipment rather than that found in typi-
cal broadcast or commercial audio gear.
High-performance components are used
throughout, providing low-distortion, low-
noise, and high headroom. Care was taken
so that signal integrity is maintained in both
the analog and digital domains.
Audio Meters and Status LEDs
The Model 44D provides four 5-segment
LED meters. The meters, located on the
front panel, display the level of the audio
signals associated with the two line inputs
and two line outputs. At the time of instal-
lation and setup the meters are invaluable
in helping to confirm correct operation.
During normal operation the meters offer
direct confirmation of the unit’s audio signal
levels, helping to ensure that optimal au-
dio quality is maintained. Additional LED
indicators are provided on the front panel,
offering status indications of the incoming
power and general purpose output (GPO)
functions.
Tone Generator Mode
For special applications the Model 44D can
be configured to serve as a tone generator.
Instead of functioning as an audio interface
device, the Model 44D will generate two
sine-wave audio signals, one 1 kHz and the
other 18 kHz. These signals are available
both as line-level analog and Dante digi-
tal audio (transmitter) outputs. The Model
44D’s generator mode is intended for use
with matrix intercom systems that are used
with the Studio Technologies’ Model 5422
Dante Intercom Audio Engine. The 18 kHz
signal will be connected to a matrix inter-
com system using either analog or Dante
inputs. The matrix intercom system will be
configured such that it will combine voice
audio with the 18 kHz tone to create spe-
cialized IFB signals. These voice-with-tone
signals will be routed, by way of an audio
transport system, to Model 5422 interrupt
inputs associated with tone operated (TOX)
IFB channels. The Model 5422 will detect
the 18 kHz tone and “trigger” the associ-
ated IFB function. In this way high-perfor-
mance IFB functions can be implemented
for REMI (remote-production) applications.
The 1 kHz tone that is generated by the
Model 44D is provided for general-purpose
use. It can also be used as a troubleshoot-
ing resource when configuring matrix
intercom systems for tone-operated (TOX)
IFB operation. Both the 1 kHz and 18 kHz
tones are precise in terms of frequency and
level accuracy, as well as being very low in
harmonic distortion.
Ethernet Data, PoE, and DC
Power Source
The Model 44D connects to a data network
using a standard 100 Mb/s twisted-pair
Ethernet interface. The physical intercon-
nection is made by way of a Neutrik®
etherCON RJ45 connector. While compat-
ible with standard RJ45 plugs, etherCON
allows a ruggedized and locking intercon-
nection for harsh or high-reliability environ-
ments. The Model 44D’s operating power
can be provided by way of the Ethernet
interface using the Power-over-Ethernet
(PoE) standard. This allows fast and
Model 44D User Guide Issue 2, November 2017
Studio Technologies, Inc. Page 9
efficient interconnection with the associ-
ated data network. To support PoE power
management, the Model 44D’s PoE inter-
face reports to the power sourcing equip-
ment (PSE) that it is a class 1 (very low
power) device. The unit can also be pow-
ered using an external source of 12 volts
DC. Four LEDs on the back panel display
the status of the network connection,
Dante interface, and PoE power source.
Simple Installation
The Model 44D uses standard connectors
to allow fast and convenient interconnec-
tions. An Ethernet signal is connected
using a Neutrik etherCON RJ45. If Power-
over-Ethernet (PoE) is available operation
will commence immediately. An external
12 volt DC power source can also be con-
nected by way of a 4-pin XLR connector.
Line input and line output connections are
made using 3-pin XLR connectors. A 9-pin
female D-subminiature (DE-9F) connec-
tor provides access to the two GPI, two
GPO, and auxiliary DC output functions.
The Model 44D is housed in a rugged yet
lightweight aluminum enclosure that is de-
signed to be “field tough.” It can be used
as a standalone portable unit, supporting
what’s known in the broadcast world as
“throw-down” applications. Rack-mount
options are also available allowing one or
two units to be mounted in one space (1U)
of a standard 19-inch rack enclosure.
Future Capabilities and
Firmware Updating
The Model 44D was designed so that its
capabilities can be enhanced in the future.
A USB connector, located on the unit’s
main circuit board (underneath the unit’s
cover), allows the application firmware
(embedded software) to be updated using
a USB flash drive.
To implement the Dante interface the
Model 44D uses Audinate’s Ultimo™
integrated circuit. The firmware in this
integrated circuit can be updated via the
unit’s Ethernet connection, helping to en-
sure that its capabilities remain up to date.
Getting Started
In this section signal interconnections will
be made using the variety of connectors
located on the Model 44D’s back panel.
Connections to the two line inputs and two
line outputs will be made using 3-pin male
and female XLR connectors. An Ethernet
data connection will be made using either
a standard RJ45 patch cable or an ether-
CON protected RJ45 plug. A 4-pin XLR
connector allows the connection of an
external source of 12 volts DC. Interfacing
with the GPI, GPO, and auxiliary DC out-
put functions can be made using a 9-pin
female D-subminiature (DE-9F) connector.
System Components
Included in the shipping carton are the
Model 44D Interface and a printed copy
of this guide. If a rack-mount front panel
is going to be used as part of the installa-
tion it will typically be shipped in a sepa-
rate carton. If the installation or specific
application requires an external source of
12 volts DC it needs to be provided sepa-
rately. A compatible power supply, the
Studio Technologies’ PS-DC-02, is avail-
able as an option.
Locating the Model 44D
The location of the Model 44D will primar-
ily depend on being within the 100-meter
Issue 2, November 2017 Model 44D User Guide
Page 10 Studio Technologies, Inc.
(325-foot) twisted pair Ethernet cable limi-
tation. But that can be overcome by us-
ing a fiber-optic interconnect between the
Model 44D-related Ethernet switch and the
other Ethernet switches in the local-area-
network (LAN). The analog line input and
line output connections, typically being
wired as a differential (balanced) pair with
shield, can support lengthy cable runs
with negligible impact on audio quality.
Protecting the Enclosure
The Model 44D is shipped as a self-
contained unit suitable for portable use
or placement in a semi-permanent loca-
tion. Installed on the bottom of the chassis
are screw-on “bump on” protectors (also
known as “rubber feet”). These are useful
if the unit is going to be placed on sur-
faces where scratching of either the Model
44D or the surface material could take
place. The “feet” can be removed, without
the use of a tool, when rack- or custom-
mounting the unit.
Rack Mounting the Model 44D
For permanent or mobile applications it
might be desirable to mount one or two
Model 44D units into one space (1U)
of a 19-inch rack enclosure. A range of
rack-mount front panels, each purchased
separately, are available from Studio Tech-
nologies. The following provides details
on how to install Model 44D units to these
panels.
To attach a Model 44D unit to the single-
unit rack-mount panel, begin the process
by using a 5/64-inch hex wrench to re-
move the four 6-32 thread button-head
cap screws that hold the standard front
panel to the chassis. Note that the screws
might be quite tightly affixed. Ensure that
a good-quality hex wrench is used and
press and hold it firmly into each screw
head while turning counterclockwise. Un-
less this recommendation is followed the
hex wrench could “cam out” and the head
could be damaged (“stripped”).
Using the screws that were just removed,
attach the rack-adapter front panel to the
Model 44D’s chassis. To prevent damage
care is required when aligning the front
panel with the LEDs that protrude slightly
through both the Model 44D’s chassis
and front panel. Tighten the four screws
only after a careful inspection ensures
that all of the LEDs protrude through the
front panel without interference. To allow
vertical clearance in the associated rack,
remove the four “bump on” protectors
from the bottom of the chassis. They
are removed by using the fingers to
rotate them counterclockwise; no tool
is required. It’s probably a good idea to
carefully protect and store the standard
front panel, along with the “bump on”
protectors, for possible later use.
Mounting a Model 44D to a dual-unit rack-
mount panel follows the same procedure
but will apply to two units. Store both of
the removed standard front panels and
the eight “bump on” protectors for possi-
ble later use. Note that on the rack-panel’s
graphics the Model 44D unit that’s on the
left is designated as A while the unit on
the right is designated as B. This is pro-
vided so that each can be easily identified
during installation, troubleshooting, and
operation.
Once the desired one or two Model 44D
units have been installed in a rack-mount
front panel, the assembly can be mounted
into the designated equipment rack.
One space (“1U” or 1.75 vertical inches)
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