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Highlights
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Excellent audio quality
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Configuration flexibility
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Simple user interface
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Next-generation performance
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Standard connectors
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Digital audio inputs and outputs
Overview
The Model 212
Announcer’s Console is designed to serve as the audio control center
for announcers, commentators, and production talent. With its
digital audio input and output resources the tabletop unit is well
suited for numerous applications including on-air television sports
broadcasting. The broadcast-standard interfaces allow direct
integration into contemporary “all digital” environments. The Model
212 integrates all on-air, talkback, and cue audio signal routing
into one compact system. Ease of use, flexible in configuration, and
sonically excellent are some of the unit’s highlights.
Whether it’s
microphone pre-amplification, switching of main and talkback audio
signals, or the headphone cue feed output, superior audio quality is
maintained throughout. A microprocessor provides the Model 212’s
logic power, allowing precise control of the unit’s operation. A
range of configuration choices allows the desired operating
configuration to be easily selected. While flexible, the user is
presented with an easy-to-use set of controls and indicators. The
digital audio interfaces are directly compatible with system
environments that use AES digital audio signals as their preferred
transmission method. Unbalanced, 75 ohm interfaces (AES3id) are standard with
balanced 110 ohm (AES3) support also available.
A truly
next-generation product, extensive research into the needs and
desires of field production personnel was integral to the Model
212’s creation. While primarily targeted for on-air television
applications, specialized features are included to allow the Model
212 to be used in a variety of other audio applications. These
include on-air radio broadcasting, stadium announcement, and
voice-over/narration booths.
Microphone Input
A high-performance
microphone preamplifier circuit provides low-noise/low-distortion
amplification over a 10 to 50 dB gain range. The gain is adjustable
in 10 dB steps. The input is compatible with balanced dynamic or
condenser microphones. The microphone power source is 48 volts
nominal and meets the worldwide P48 phantom standard. An LED
indicator serves as an aid for optimizing the setting of the
preamplifier’s gain. The output of the microphone preamplifier is
routed to the compressor circuit that supports the main and talkback
audio channels.
Dynamic Range Control
A studio-quality
compressor circuit is provided to control the dynamic range of the
analog signal coming from the microphone preamplifier. Far from a
simple “clipper,” the circuit utilizes a sophisticated laser-trimmed
voltage-controlled-amplifier (VCA) integrated circuit for quiet,
low-distortion level control. The output of the compressor is used
by the main and talkback channels, being routed to the inputs of
their respective analog-to-digital converter circuits. The threshold
of the compressor can be configured from among two values. When
configured for –4 dBFS dynamic range control will only take place as
the signal approaches the level limit of the digital signal. During
normal operation the compressor would not be active. With the
compressor configured to –14 dBFS some dynamic range control would
be expected during normal operation. While not appropriate for major
on-air situations, having dynamic range control of the signal can
offer increased performance for many applications. This would be
appropriate for applications such as stadium announcement positions,
sports events using nonprofessional on-air talent, as well as
situations where the risk of digital “clipping” is present.
Main and Talkback Audio Channels
Internally, the Model 212 creates analog main and talkback audio
channels. The main audio channel is designed to serve as the on-air,
stadium announcement, or other primary audio feed. The talkback
audio channel is intended to provide production trucks, control
rooms, or support personnel with a talent-originated cue signal. The
two analog channels are converted to 24-bit PCM digital audio and
multiplexed and formatted into an AES digital audio “stream.” The
A/D converters and digital transmitter circuitry is synchronized
(“locked”) to the selected digital input signal. The system will
automatically revert to the internal clock, which provides a 48 kHz
sampling rate. The main audio channel is assigned to digital channel
1 with talkback audio on digital channel 2. The composite digital
audio signal is routed to two physical interfaces. One output is
AES3id compliant (unbalanced, 75 ohms) with a BNC connector for
interfacing. This professional interface is transformer-coupled and
capable of driving long broadcast cable runs.
The
digital audio output signal is also routed to a unique bidirectional
digital interface. Similar to AES3id, it uses a BNC connector and
supports two channels of audio in each direction over a single 75
ohm cable. The bidirectional audio interface will find use in
specialized applications, including direct integration with Riedel®
intercom systems. Note that audio signals received from the
bidirectional interface are described in the Cue Sources section of
this document.
For
enhanced flexibility, the Model 212 includes the resources to
support a third digital output. Circuitry, located on the printed
circuit board assembly, creates an AES3 compliant, 110 ohm nominal,
transformer-balanced digital output. Gaining access to this output
simply requires adding a 3-pin male XLR-type connector to one of the
two spare connector locations on the Model 212’s back panel.
Connector kits, available from Studio Technologies, make this a
simple task.
For
specialized applications an optional direct microphone output card
is available. This allows the Model 212 to support an analog signal
chain for the main output channel. Of course this output also
provides “click-free” microphone on/off (“muting”) control.
The
Model 212 isn’t limited for use in “on-air” applications. A special
feature can be enabled, placing the unit in a “production” mode.
When this mode is active enabling the talkback audio channel will no
longer force the main audio channel to mute. This allows the main
audio channel to be used as a second talkback output. In this
configuration the unit can be even more powerful when used in a live
event application, such as serving as a master console for a
production director.
User Controls and Status Indicators
Two
pushbutton switches, three LED indicators, and two rotary controls
provide the user with a clear, easy-to-use interface. One pushbutton
switch controls the status of the main audio channel. This is the
audio signal intended for on-air, announcement, or other primary
uses. Two LEDs display the on/off status of the main audio channel.
A second pushbutton switch controls the status of the talkback audio channel.
This is the audio signal used to communicate with producers,
directors, spotters, or other behind-the-scenes production
personnel. A status LED is associated with the talkback button. Two
rotary controls allow the user to adjust the level of the stereo
headphone output.
Operational Flexibility
Much of the Model
212’s unique capabilities derive from the ability to configure the
on/off control of the main and talkback audio channels. To meet the
needs of the many specific broadcast and production applications, a
variety of button operating modes are available. The main button,
located on the left side of the front panel, can be selected to
operate from among four modes. In the “push-to-mute” mode the button
performs a momentary mute of the main audio channel. In this way a
“cough” button function is created, something typically required for
television sports broadcasting. In the “push-to-talk” mode the
button provides a momentary active function for the main audio
channel. This mode would be appropriate for applications such as
stadium announcement. An alternate action “latching” configuration
allows the button to enable or disable the main audio channel as
desired. This is useful in radio broadcasting, announce-booth, or
voice-over applications. The fourth mode provides a hybrid function,
supporting both push-to-talk and tap-to-enable/tap-to-disable
operation. This operation is similar to that found in many broadcast
intercom system user stations.
The button associated
with the talkback function can be configured to operate from either
of two modes. One of the modes supports a “push-to-talk” function.
This is typically used for on-air broadcast applications. The other
mode provides a hybrid function, the operation of which is discussed
in the previous paragraph. The hybrid mode is especially useful when
the Model 212 is used in a production-support application.
Cue Sources
The Model 212 allows
two audio channels from one of three digital audio sources to be
routed to the stereo headphone output. Configuration switches select
which digital input is active. The available sources are the AES3id
input, the previously discussed bidirectional digital interface, and
the optionally implemented AES3 input. The AES3id input is an
unbalanced, 75 ohm interface that uses a BNC connector.
Transformer-coupled, it is compatible with standard unbalanced
digital audio signals. The bidirectional digital interface is
similar to AES3id but carries two audio channels in each direction.
It is intended for use in special applications. The AES3 input is
balanced, 110 ohms, and to use requires the addition of a connector
on the unit’s back panel. No matter which of the digital inputs is
selected, the receiver circuitry can accept bit depths of 16 to 24.
While the nominal sample rate is 48 kHz, any signal in the range of
32 to 96 kHz is acceptable. Note that the received clock signal is
used for two purposes; it allows correct receiver synchronization as
well as serving as the transmitter clock source for the digital
outputs.
Digital-to-analog
conversion circuitry creates two analog “cue” audio signals
from the selected digital interface. In on-air broadcast
applications these cue signals, originating in production trailers,
control rooms, or remote locations, supply program-with-interrupt
audio on one channel and program-only audio on the other. Each
source can be individually assigned to the left channel, right
channel, or both left and right. This allows a wide variety of
stereo and mono headphone mixes to be created.
Some applications may
benefit by being able to connect standard line-level audio signals
to the Model 212. To meet this need one or two optional line input
cards can be installed in the Model 212’s back panel. Each card
provides a female XLR-type connector and transformer-isolated +4 dBu
nominal input circuit. Each source can be individually assigned to
the left channel, right channel, or both left and right.
Headphone Output
Two rotary controls
are provided for user adjustment of the headphone output levels. For
application flexibility the actual function of the two “pots” is
configurable. For traditional on-air sports applications they can be
selected to the dual-channel (“level/level”) mode which provides
independent control of the left- and right-channel volume. For use
with dual-channel cue signals, or to support user preference, the
stereo (“level/balance”) mode can be selected. In this mode one
control adjusts the overall level of both the left and right
channels, while the other allows adjustment of the left/right level
balance. To help minimize the chance of broadcast cues being missed,
both level control modes can be configured so that a minimum
headphone output level is maintained. Alternately, the headphone
output can be set to fully mute when the controls are at their
minimum position. The rotary controls can also be set for a reverse
left/right mode. This is provided for cases where a user needs to
wear their headset “reversed” to support alternate camera angles.
By using this special mode intuitive operation will be maintained
and a comfortable work environment assured.
Provision has been
made to support applications where a monaural cue feed is desired. A
configuration switch allows the summing (combining) of the selected
left and right headphone sources. In addition to creating a
dual-channel mono output it also allows the level controls to be
configured as a simple 2-channel mixer.
The headphone output
was designed to meet the needs of contemporary headphones and
headsets. Specifically, the output circuits act as voltage, rather
than power, drivers. In this configuration they can provide high
output levels with very low distortion and noise, along with minimal
current consumption. The output circuits are configured to safely
drive stereo or mono loads. This ensures that all types of
headphones, headsets, and earpieces can be directly connected.
Audio Quality and Protection
The Model 212’s
circuitry was carefully tailored to provide excellent audio
performance. Professional-quality components are featured
throughout. For reliability all audio routing is performed using
solid-state devices. In all critical audio paths, “clickless”
performance is provided. All audio inputs and outputs make extensive
use of protection components. This limits the chance of damage from
ESD and other undesirable, yet real-world, hazards.
Power Sources
The
Model 212 requires an external source of nominal 24 volt DC, 150
milliamperes maximum, for operation. Inside the Model 212, an internal
switch-mode power supply creates the various voltage “rails”
required by the internal circuitry.
An
external power supply is included with each unit. As an
alternative, the Model 44 Interface can be used to power the Model
212. Available from Studio Technologies, it serves as an
interconnection “hub,” providing power and signal routing for up to
six Model 212 Announcer’s Consoles.
Auxiliary Relay
Model
212 resources include a general-purpose relay, allowing specialized
configurations to be created. Under software control, the relay can
be configured to follow the state of the main and talkback audio
channels. Taking advantage of the back-panel locations provided for
additional XLR-type connectors, a technician may easily implement a
variety of functions such as providing an “on-air” indicator or
performing loudspeaker muting during talkback.
Configuration
Model 212
configurations are made using a number of DIP-type switches. One
8-position switch array is used to set the gain of the microphone
preamplifier, the on/off status of phantom power, the compressor
threshold, and the headphone stereo/mono mode. Another 8-position
switch array configures which of the audio sources is routed to the
headphone output. A 12-position switch array communicates the
desired operating modes to the microprocessor. All switches are
accessible via the bottom of the Model 212’s enclosure; the unit
does not have to be disassembled. Changes made to any of the
configuration parameters become active immediately. To prevent
access to the configuration switches a security panel, included with
each unit, is attached to the bottom of the enclosure.
Connectors
The Model 212 uses
standard connectors throughout. The microphone input uses a 3-pin
female XLR-type connector. The digital audio inputs and outputs use
BNC connectors. A ¼-inch 3-conductor jack is used for the headphone
output. The external source of 24 volt DC power is connected by way
of a 2.1 x 5.5 mm “locking” coaxial power jack. In the world of
broadcast and production audio it’s fair to say that applications
vary widely. To this end, one or two additional XLR-type connectors
can easily be mounted into the Model 212’s back panel. Multiple
3-position “headers” located on the Model 212’s circuit board
provide technician-access to all input and output connections. Using
a factory-available interface cable kit allows a Model 212 to be
optimized to meet the exact needs of specific applications. For
example, some applications may prefer to use a multi-pin XLR-type
connector to interface with a headset. This can easily be
accomplished by adding the appropriate 5-, 6-, or 7-pin XLR-type
connector and making a few simple connections. Other applications
may benefit from having “mult” or “loop-through” connections,
something easily incorporated into a Model 212. One or two optional
line input cards, as previously discussed, can also be mounted in
the spare XLR positions.
Model 212 Specifications
General
Audio:
Frequency Response: < –0.1 dB at 20 Hz, –1 dB at 18 kHz, mic in/main out
Distortion (THD+N): 0.025%, measured at 1 kHz, mic in/main out
S/N Ratio: 71 dB, referenced to –46 dBu mic in/–14 dBFS out
Common Mode Rejection Ratio: 68 dB at 60 Hz
Connectors:
Mic In: 3-pin female XLR-type
AES3id Out, AES3id In, Bidirectional Interface: 75 ohm BNC
Headphone Out: ¼-inch 3-conductor phone jack
24 Vdc Power In: coaxial power jack, 2.1 x 5.5 mm, locking bushing,
compatible with Switchcraft S760K plug
Spare
Connector Locations: 2
Allows one or two Neutrik NC*D-L-1 connectors to be installed
(*=3F, 3M, 5F, 5M, 6F, 6FS, etc.)
Digital
Inputs/Outputs:
A/D, D/A Converters: 24 bit, 100 dB dynamic range
Sampling Rate: internal clock source 48 kHz, external clock source 32 to
96 kHz
AES3id In: unbalanced, transformer-coupled
Impedance: 75 ohms
Minimum Input Carrier Amplitude: 320 mVpp (SPDIF compatible)
AES3id Out: unbalanced, transformer-coupled
Impedance: 75 ohms
Output Carrier Amplitude (Loaded): 1 Vpp
Bidirectional: unbalanced transformer-coupled
Impedance: 75 ohms
Output Carrier Amplitude (Loaded): 1.75 Vpp
Minimum Input Carrier Amplitude: 320 mVpp
AES3 In: balanced, transformer-coupled (via optional connector)
Impedance: 110 ohms
Minimum Input Carrier Amplitude: 200 mVpp
AES3 Out: balanced, transformer-coupled (via optional connector)
Impedance: 110 ohms
Output Carrier Amplitude (Loaded): 3.5 Vpp
Microphone Input/Preamplifier:
Type: electronically balanced
Input Impedance: 2 k ohms, nominal
Gain Range: 10 to 50 dB, nominal, adjustable in 10 dB steps
Compatibility: dynamic or phantom-powered mics
Phantom Power: 48 Vdc, nominal, meets IEC 61938
Optional
Line Inputs: 2
Type: balanced, transformer-coupled
Impedance: 10 k ohms, nominal
Nominal Level: +4 dBu
Compressor:
Threshold: switchable –14 dBFS/–4 dBFS
Attack/Release Time: 2 mSec/100 mSec, nominal
Slope: 5:1, nominal
Status LED: compressor active
Headphone
Output: 1, stereo
Compatibility: intended for connection to mono or stereo headphones or
headsets with nominal impedance of 100 ohms or greater
Type: voltage driver
Maximum Output Voltage: 8 Vpp, 150 ohm load
Auxiliary
Relay:
Function: software configurable
Contacts: 2, form C (Common, Normally Closed, Normally Open)
Rating: 1 A, 30 W (resistive)
Access: requires user-implemented connector scheme
Power
Source:
24 Vdc nominal, 150 mA max @ 24 Vdc; acceptable range 20-30 Vdc.
Units shipped to North America and Japan include a 120 V input/24 Vdc
output power supply. Units shipped to all other locations include a
universal input/24 Vdc output power supply.
Options:
One or two optional XLR cards can be installed to provide support for
connection of AES3, line-level balanced or unbalanced audio sources
Dimensions (Overall):
5.6 inches wide (14.2 cm)
3.3 inches high (8.4 cm)
8.5 inches deep (22.4 cm)
Weight:
3.2 pounds (1.45 kg)
Specifications
subject to change without notice.
Model 200-Series Announcer's Consoles
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Which
Announcer's Console is right for your application? Review the
Model 200-Series
Announcer's Consoles Feature-by-Feature Comparison Chart.
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A
host of optional accessories can be added on to the
Model 200-Series Announcer's Consoles. For more information review the
Model 200-Series
Announcer's Consoles Accessories List.
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Need
to power and connect multiple announcer's consoles? See the
Model 44 Interface.
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