Wheatstone Corporation AirAura X1 User manual
FM & HD Digital auDio Processor
AirAura X1
600 Industrial Drive, New Bern, North Carolina 28562 (tel 252-638-7000 / fax 252-637-1285 )
Technical
Manual
Technical
Manual
Wheatstone Corporation
December 2016
FM & HD Digital auDio Processor
AirAura X1
600 Industrial Drive
New Bern, North Carolina 28562
tel 252-638-7000 / fax 252-637-1285
AirAura X1 FM & HD Digital Audio Processor Technical Manual
©2016 Wheatstone Corporation
AirAura X1 / Dec 2016
Wheatstone audio Processing
page Contents – 1
AirAura X3 / May 2013
CONTENTS
AirAura X1 Technical Manual
Chapter 1 - General Information
Table of Contents
Introduction ....................................................................................1-2
X1 Feature Overview .....................................................................1-3
Rack Mounting ...............................................................................1-4
X1 Installation Tips .....................................................................................................1-5
Grounding................................................................................................................1-5
Surge Protection......................................................................................................1-5
UPS/Power Conditioning ........................................................................................1-5
Analog Audio Input Connections.............................................................................1-5
Analog Audio Output Connections..........................................................................1-6
Digital Audio Connections.......................................................................................1-6
Where to Install X1 .....................................................................................................1-7
Digital STL ...............................................................................................................1-7
Analog Left/Right STL .............................................................................................1-8
Composite Analog STL ...........................................................................................1-8
Analog Phone Lines ................................................................................................1-9
Arbitron People Meter (PPM)™...............................................................................1-9
AC Power Considerations .............................................................1-9
Rear Panel Connections ..............................................................1-10
Audio Inputs ..............................................................................................................1-11
Analog In ................................................................................................................1-11
AES In.....................................................................................................................1-11
SCA In ....................................................................................................................1-11
Audio Outputs ...........................................................................................................1-11
FM Path..................................................................................................................1-11
HD Path ..................................................................................................................1-12
Insert Loop Out ......................................................................................................1-12
Insert Loop IN.........................................................................................................1-12
FM/HD Analog Out.................................................................................................1-12
FM AES / baseband192 Out ..................................................................................1-12
HD AES Out............................................................................................................1-12
TX Out ....................................................................................................................1-12
Headphone Monitoring..............................................................................................1-12
Network Connections................................................................................................1-13
Ethernet ..................................................................................................................1-13
Typical Straight-Through Cable Cable ...................................................................1-13
Typical Crossover Cable.........................................................................................1-13
General Purpose Interface (GPI/GPO).......................................................................1-14
GPI..........................................................................................................................1-14
GPO........................................................................................................................1-14
Starting With a Preset ............................................................................................1-15
Processing Presets.................................................................................................1-15
Analog XLR Connections Pinouts Drawing ...............................................................1-17
Digital XLR Connections Pinouts Drawing ................................................................1-18
BNC Connections Pinouts Drawing ..........................................................................1-19
Ethernet RJ-45/General Purpose Interface DB-9 Pinouts Drawing .........................1-20
page Contents – 2
AirAura X3 / May 2013
CONTENTS
Input Screen ...................................................................................2-3
Input Source...............................................................................................................2-3
Digital Gain .................................................................................................................2-4
Analog Gain................................................................................................................2-4
L/R Balance................................................................................................................2-4
Phase Rotator.............................................................................................................2-4
High Pass Filter ..........................................................................................................2-4
Automatic Failover......................................................................................................2-5
Insert Loop Option .....................................................................................................2-5
5 Band iACC ...................................................................................2-6
AGC Drive...................................................................................................................2-6
LF Density ..................................................................................................................2-6
HF Density..................................................................................................................2-6
Attack Master .............................................................................................................2-7
Release Master...........................................................................................................2-7
Gate Offset .................................................................................................................2-7
10-Band FM Limiter .......................................................................2-8
MB Limiter Drive.........................................................................................................2-8
Threshold Master .......................................................................................................2-8
Attack Master .............................................................................................................2-9
Release Master...........................................................................................................2-9
Clip Drive....................................................................................................................2-9
Pre-Emphasis .............................................................................................................2-9
Where and When to Use Pre-Emphasis and De-Emphasis ...................................2-10
10-Band HD Limiter ......................................................................2-11
MB Limiter Drive........................................................................................................2-11
Threshold Master ......................................................................................................2-11
Attack Master ............................................................................................................2-12
Release Master..........................................................................................................2-12
HD Final Limiter ............................................................................2-13
Limiter Drive ..............................................................................................................2-13
Limiter Threshold.......................................................................................................2-13
Attack ........................................................................................................................2-14
Release......................................................................................................................2-14
Delayed Release........................................................................................................2-14
FM Final Clipper ............................................................................2-15
Main Clipper Drive.....................................................................................................2-15
Multipath Limiter........................................................................................................2-15
Composite Clipper Drive ...........................................................................................2-16
ITU/BS.412 Controller ...............................................................................................2-16
FM TX Controls .............................................................................2-17
Encoder Mode...........................................................................................................2-17
Pilot Injection.............................................................................................................2-17
TX 1 and 2 Level........................................................................................................2-18
SCA 1 and 2 Level.....................................................................................................2-18
Chapter 2 - Front Panel GUI
page Contents – 3
AirAura X3 / May 2013
CONTENTS
FM L/R Output Controls ...............................................................2-19
Digital Output Mode ..................................................................................................2-19
Digital Output Level...................................................................................................2-19
Digital Emphasis........................................................................................................2-20
Analog Out + Emphasis.............................................................................................2-20
Analog Output Level..................................................................................................2-20
HD Output Screen .........................................................................2-21
Left/Right Swap.........................................................................................................2-21
Digital Phase .............................................................................................................2-21
Digital Level ...............................................................................................................2-22
System ...........................................................................................2-23
I/O Settings Follow Presets.......................................................................................2-23
Input/Output Settings Change With Preset Takes..................................................2-23
Network .....................................................................................................................2-24
Front Panel IP Address (FP) ......................................................................................2-25
Hardware IP Address (HW)........................................................................................2-25
Subnet Mask .............................................................................................................2-25
Diversity Delay...........................................................................................................2-25
Control Timeout.........................................................................................................2-26
Security .....................................................................................................................2-26
Versions .....................................................................................................................2-27
Status ........................................................................................................................2-27
Saving Your Work ......................................................................................................2-28
Getting Started ..............................................................................3-5
Connecting With The Pro GUI .......................................................3-5
Connecting Directly Without a LAN............................................................................3-6
The X1 and Internet Security Concerns .....................................................................3-7
About DHCP and The X1............................................................................................3-7
AirAura Network Protocols and Ports Used...............................................................3-7
Using The X1 Pro GUI ....................................................................3-8
Metering .....................................................................................................................3-8
Input Meters ............................................................................................................3-8
Multiband AGC and Enhance Meters......................................................................3-9
10-Band Limiter Metering .......................................................................................3-9
Final Limiting Meters ...............................................................................................3-9
Output Metering .....................................................................................................3-10
GUI Adjustment Controls ..........................................................................................3-10
Input Setup Menu...................................................................................................3-10
Source Selection and Automatic Failover ...........................................................3-11
Input Gain, Balance, and Input Loop ..................................................................3-11
Analog Input Gain.............................................................................................3-11
Digital Input Gain..............................................................................................3-11
L/R Balance......................................................................................................3-12
Enable Insert Loop ...........................................................................................3-12
Codec Masking ...................................................................................................3-13
High Pass Filter ...................................................................................................3-14
Chapter 3 - X1 Pro GUI
page Contents – 4
AirAura X3 / May 2013
CONTENTS
Miscellaneous......................................................................................................3-14
Phase Rotator...................................................................................................3-14
Input Settings Follow Preset Takes ..................................................................3-15
Equalizer Menu.......................................................................................................3-15
EQ Enable............................................................................................................3-16
iAGC and Compressor ...........................................................................................3-17
iAGC ....................................................................................................................3-18
Window Size.....................................................................................................3-18
Attack Speed....................................................................................................3-18
Release Speed .................................................................................................3-18
Adapt Mode......................................................................................................3-18
iAGC Gate Threshold .......................................................................................3-19
Return To Zero (RTZ) ........................................................................................3-19
Master .................................................................................................................3-19
Multiband Master Drive ....................................................................................3-19
Multiband Coupling Reference.........................................................................3-20
Main AGC Gate Mode ......................................................................................3-20
Bypass Options................................................................................................3-20
Band Tabs (1-5) ...................................................................................................3-21
Density (Basic Control).....................................................................................3-21
Band Mix (Basic Control)..................................................................................3-21
Master Attack (Basic Control)...........................................................................3-22
Master Release (Basic Control) ........................................................................3-22
Band Threshold (Expert Control) ......................................................................3-22
Ratio (Expert Control) .......................................................................................3-22
Band Coupling (Expert Control) .......................................................................3-23
Compressor Attack (Expert Control) ................................................................3-23
Compressor Release (Expert Control)..............................................................3-23
Crossover Control (Expert Control) ..................................................................3-24
Effect Tab.............................................................................................................3-24
HD Limiter ..............................................................................................................3-26
Multiband Drive (Basic Control)...........................................................................3-26
Limiter Drive (Basic Control)................................................................................3-27
Multiband Knee (Basic Control)...........................................................................3-27
L/R Linked (Basic Control)...................................................................................3-27
Bass Style (Basic Control)...................................................................................3-28
Master Attack (Expert Control)............................................................................3-28
Master Limiter Release (Expert Control)..............................................................3-28
Wideband Delayed Release (Expert Control) ......................................................3-28
Master Threshold (Expert Control) ......................................................................3-28
Wideband Threshold (Expert Control) .................................................................3-29
Filter Frequency (Expert Control).........................................................................3-29
Filter Style (Expert Control)..................................................................................3-29
Bass Clip Threshold (Expert Control) ..................................................................3-29
Bass Texture (Expert Control)..............................................................................3-30
FM Limiter ..............................................................................................................3-30
Multiband Drive (Basic Control)...........................................................................3-30
Clipper Drive (Basic Control) ...............................................................................3-31
Bass Enhance (Basic Control).............................................................................3-31
Multiband Knee (Basic Control)...........................................................................3-31
Pre-Emphasis (Basic Control) .............................................................................3-32
Where Should Pre-Emphasis Go?....................................................................3-32
page Contents – 5
AirAura X3 / May 2013
CONTENTS
Bass Style (Basic Control)...................................................................................3-32
Master Attack (Expert Control)............................................................................3-32
Master Threshold (Expert Control) ......................................................................3-33
Filter Frequency (Expert Control).........................................................................3-33
Filter Style (Expert Control)..................................................................................3-33
Bass Clip Threshold (Expert Control) ..................................................................3-33
Bass Texture (Expert Control)..............................................................................3-34
MPX & Output ........................................................................................................3-35
Process & SCA Tab .............................................................................................3-35
Encoder Mode (Processing) .............................................................................3-35
MPX Processing (Processing) ..........................................................................3-35
MPX Process Style (Processing) ......................................................................3-36
Multipath Limiter (Processing)..........................................................................3-36
Pilot Level (Processing) ....................................................................................3-37
BS.412 Processing (BS.412 MPX Power Control)............................................3-37
BS.412 Peak Style (BS.412 MPX Power Control) ............................................3-38
BS.412 Speed (BS.412 MPX Power Control)...................................................3-38
BS.412 MPX Power (BS.412 MPX Power Control) ..........................................3-38
BS.412 Calibration Offset (BS.412 MPX Power Control) .................................3-38
BS.412 Action (BS.412 MPX Power Control) ...................................................3-39
SCA 1 and SCA 2 Inputs (Subcarrier Inputs) ...................................................3-39
Output Tab...........................................................................................................3-40
TX1 and TX2 Outputs (Analog MPX) ................................................................3-40
TX2 Mode (Analog MPX) ..................................................................................3-40
Source (Analog L/R) .........................................................................................3-41
Level (Analog L/R) ............................................................................................3-41
Pre-Delay (Analog L/R) .....................................................................................3-41
De-Emphasis (Analog L/R) ...............................................................................3-41
Level (FM Digital)..............................................................................................3-41
Type (FM Digital) ...............................................................................................3-41
Pre-Delay (FM Digital).......................................................................................3-42
De-Emphasis (FM Digital).................................................................................3-42
Level (HD Digital) ..............................................................................................3-43
Phase Reverse (HD Digital) ..............................................................................3-43
L/R Swap (HD Digital).......................................................................................3-43
Delay & Test Tab ..................................................................................................3-44
Diversity Delay..................................................................................................3-44
Test Oscillator...................................................................................................3-45
System ...................................................................................................................3-46
Front Panel Security Settings..............................................................................3-46
Lost Passwords................................................................................................3-47
Time Features/Dayparting ...................................................................................3-47
Preset Scheduler ..............................................................................................3-47
Creating a Weekly Rotation Schedule ...........................................................3-48
Creating a Long Term Rotation Schedule .....................................................3-48
Deleting a Scheduled Event ..........................................................................3-48
System Time.....................................................................................................3-49
Options and Status .............................................................................................3-49
Miscellaneous......................................................................................................3-50
Headphone Source ..........................................................................................3-50
Control Timeout................................................................................................3-51
page Contents – 6
AirAura X3 / May 2013
CONTENTS
Presets ................................................................................................................3-51
List....................................................................................................................3-51
Save..................................................................................................................3-52
Library ..............................................................................................................3-52
Locking Presets................................................................................................3-52
How To View Preset Differences.......................................................................3-53
Hardware .............................................................................................................3-53
Analysis ............................................................................................................3-53
Analysis Source.............................................................................................3-53
FM & HD Analysis Options Type ...................................................................3-54
FFT ................................................................................................................3-54
3-D Plot .........................................................................................................3-55
BS-1770 Loudness........................................................................................3-55
O-Scope ........................................................................................................3-56
E vs. F............................................................................................................3-56
SDR™............................................................................................................3-57
Stereo ............................................................................................................3-57
A-Clip ............................................................................................................3-58
MPX Analysis Options...................................................................................3-58
Devices.............................................................................................................3-59
X1 Hardware Update ........................................................................................3-59
X1 Sub Menus .....................................................................................................3-62
View..................................................................................................................3-62
Hardware ..........................................................................................................3-62
Presets .............................................................................................................3-63
General Specifications ..................................................................A-3
X1’s GPIO Interface .......................................................................A-9
GPI - General Purpose Input ......................................................................................A-9
GPO - General Purpose Output ................................................................................A-11
Interpreting Common Audio Processing Terms ........................A-14
Background...............................................................................................................A-14
Audio Terms and Wheatstone Processing ................................................................A-15
Thump/Rumble/Bottom..........................................................................................A-15
Punch/Boom/Tubby/Warm.....................................................................................A-16
Mud ........................................................................................................................A-16
Honk .......................................................................................................................A-16
Whack ....................................................................................................................A-16
Fuzzy/Tinny ............................................................................................................A-17
Appendices
Appendix A
Appendix C
Appendix B
page Contents – 7
AirAura X3 / May 2013
CONTENTS
Crunchy/Edgy.........................................................................................................A-17
Sibilance.................................................................................................................A-18
Treble/Bright/Open .................................................................................................A-18
Finally .....................................................................................................................A-18
WheatNet-IP Configuration ..........................................................A-20
Adding the X1 to The WheatNet-IP System..............................................................A-21
Appendix D
page 1 – 1
AirAura X1 / Dec 2016
GENERAL INFORMATION
General Information
Introduction....................................................................................1-2
X1 Feature Overview .....................................................................1-3
Rack Mounting...............................................................................1-4
X1 Installation Tips .....................................................................................................1-5
Grounding................................................................................................................1-5
Surge Protection......................................................................................................1-5
UPS/Power Conditioning ........................................................................................1-5
Analog Audio Input Connections.............................................................................1-5
Analog Audio Output Connections..........................................................................1-6
Digital Audio Connections.......................................................................................1-6
Where to Install X1 .....................................................................................................1-7
Digital STL ...............................................................................................................1-7
Analog Left/Right STL .............................................................................................1-8
Composite Analog STL ...........................................................................................1-8
Analog Phone Lines ................................................................................................1-9
Arbitron People Meter (PPM)™...............................................................................1-9
AC Power Considerations ............................................................1-9
Rear Panel Connections ..............................................................1-10
Audio Inputs ..............................................................................................................1-11
Analog In ................................................................................................................1-11
AES In.....................................................................................................................1-11
SCA In ....................................................................................................................1-11
Audio Outputs ...........................................................................................................1-11
FM Path..................................................................................................................1-11
HD Path ..................................................................................................................1-12
Insert Loop Out ......................................................................................................1-12
Insert Loop IN.........................................................................................................1-12
FM/HD Analog Out.................................................................................................1-12
FM AES / baseband192 Out ..................................................................................1-12
HD AES Out............................................................................................................1-12
TX Out ....................................................................................................................1-12
Headphone Monitoring..............................................................................................1-12
Network Connections................................................................................................1-13
Ethernet ..................................................................................................................1-13
Typical Straight-Through Cable Cable ...................................................................1-13
Typical Crossover Cable.........................................................................................1-13
General Purpose Interface (GPI/GPO).......................................................................1-14
GPI..........................................................................................................................1-14
GPO........................................................................................................................1-14
Starting With a Preset ............................................................................................1-15
Processing Presets.................................................................................................1-15
Analog XLR Connections Pinouts Drawing ...............................................................1-17
Digital XLR Connections Pinouts Drawing ................................................................1-18
BNC Connections Pinouts Drawing ..........................................................................1-19
Ethernet RJ-45/General Purpose Interface DB-9 Pinouts Drawing .........................1-20
Chapter Contents
page 1 – 2
AirAura X1 / Dec 2016
GENERAL INFORMATION
General Information
Introduction
Welcome to the Wheatstone X1 FM and HD Digital Audio Processor, an exciting part
of Wheatstone’s third generation of audio processing. The X1 expands on technologies
previously invented by Wheatstone, incorporates several new technologies, and delivers
that “sought after” sound to the FM and HD mediums.
The X1’s processing algorithms have evolved from our highly popular FM‑55 broadcast
audio processor. The X1 package builds on the great sound and simple setup of the FM‑55
and adds a second processing path for HD as well as an insert point for a ratings encoder.
The X1 is the rst part of a brand new approach to processing from Wheatstone that
we call UNIFIED PROCESSING. Unied Processing means the entire processor is self-
aware of all the processing stages, how they are working, and what decisions the individual
blocks have to make to generate a unique and consistent sound from source to source, no
matter what the dynamic range or level.
The X1’s unied algorithms include a brand new program aware 10-band limiter
(never before offered at this level in any broadcast processor) that takes the effortless
sound of the FM‑55 platform to a new level. Coupled with our proven iAGC program
density controller, specialized low distortion, low IMD clipper for FM and codec aware
HD processing, the X1 stands above all other processors in its price class.
Remote control of X1 is via Windows‑based Graphical User Interface (GUI) software
and can be accomplished via 100BaseT wired Ethernet. The X1 GUI incorporates two
layers of controls… one for expert users and one for basic users. This means that even
inexperienced users can have condence in setting up and adjusting the processor.
Eight rear panel General Purpose Inputs (GPI) and four General Purpose Outputs
(GPO) are provided to allow hardware‑level interfacing of the X1 to station systems.
The X1 provides the user with the ability to insert the ratings encoder and any associated
gear directly into the processing path. This wraps the encoder around the audio proces‑
sor to potentially increase the chances of ratings credit. The front end of the X1 thereby
acts as a program density controller for the ratings encoder, ensuring that there is always
ample program level to embed the watermark. Previously, one had to place the ratings
encoder BEFORE the audio processor and run the risk of the multiband section of the
audio processing skewing the watermark tones. With the X1, placement is AFTER the
bulk of the multiband section, leaving the watermark intact and with the potential for
higher recognition by the meter.
page 1 – 3
AirAura X1 / Dec 2016
GENERAL INFORMATION
The X1 utilizes an internal base sampling rate of 192 kHz. Far higher sample rates
are used where it is benecial to do so, such as within the X1 clipper. A 24-bit, 144dB
internal dynamic range signal path allows audio to be processed with extreme precision.
The single front panel touchscreen and control knob allows users easy operation of most
key controls to set up and adjust the processor.
All Wheatstone products are designed and manufactured byWheatstone in its Corporate
Headquarters in New Bern, North Carolina, USA. This large, state of the art facility affords
complete control over product quality during every step of the manufacturing process. In
order to maintain the high product quality standards that Wheatstone is known for for over
40 years, no offshore manufacturing is utilized.
If during installation or setup you nd that you need assistance or advice, please
feel free to contact our technical support folks at (252) 638-7000 or email us at:
X1 Feature Overview
The X1 digital audio processor has been designed to separately process audio for
conventional analog FM and digital HD radio signals. Sharing the four‑band parametric
equalizer and intelligent ve band leveler with iAGC, the FM and HD paths are equipped
with individual “program aware” 10-band limiter sections and peak controlling processors
which have been optimized for the respective broadcast mediums.
The X1’s ve band leveler incorporates Wheatstone’s specialized iAGC (Intelligent AGC)
algorithm. and operates through a proprietary technique called Density Compensation™.
The Density Compensation™ algorithm utilizes real‑time analysis of the pre and
post-processed audio, and data from the processing controls as the user has adjusted them,
to invisibly manage the user set spectral balance and program density. The output of the
ve band leveler can then be patched to an external ratings encoder device. Upon return
to the processor, the audio is then split into two signal paths, FM and HD, each equipped
with our 10-band “program aware” limiter.
The FM signal path is equipped with a newly rened FM clipper. Borrowing a little
from our FM-55 audio processor, this new FM clipper works with the 10-band limiter to
automatically determine the best course of action to maintain loudness and clarity. The
result is a higher average level of audio without the traditional tradeoffs you would nd
in other designs that were “trying” to be loud.
A digitally perfect stereo generator follows the clipper and provides two multiplex
composite stereo outputs and two SCA inputs.
The X1 is also fully compatible with exciters that accept composite audio delivered over
an AES connection. Wheatstone’s baseband192 system includes audio and subcarriers up
to and including 67kHz in an AES format. This system eliminates the need to transition
back to analog when using the built in stereo generator in your audio processor. It also
maintains a complete digital path without sacricing loudness or having to use the stereo
generator built into the exciter.
The HD signal path is equipped with its own 10-band limiter followed by a smart look-
ahead nal limiter with adjustable operating parameters which allow program density and
peak control to be set as desired. The HD path’s digital and analog outputs may be swapped
left for right as well as phase reversed if needed.
page 1 – 4
AirAura X1 / Dec 2016
GENERAL INFORMATION
The X1 is equipped with Wheatstone’s network‑based ACI protocol, allowing complete
control of not only presets, but any parameter that is assigned to a user control (please
contact the factory for details on this). The ACI also allows the X1 to receive time align‑
ment commands from external devices to correct for alignment errors in the processor. For
more information on HD time alignment products that are compatible with the X1, please
visit our website at http://www.wheatstone-processing.com.
Dozens of factory presets are provided with X1 making a wide range of on air sounds
available to the user. A fully routable headphone monitoring path allows the audio in
various parts of the processing chain to be auditioned.
The System Menu of the GUI provides access to a pair of exible preset scheduling
utilities. As well as the usual short‑term scheduler, the X1 is equipped with a “long‑form”
scheduler feature that can be programmed for automatic preset changes well into the future.
This scheduler is useful for changing presets weeks or months after a preset is prepared,
such as for a special event, and without having to edit the daily preset schedule in order
to accommodate these “special” presets.
GPI (General Purpose Inputs) provide easy access to preset changes via external events
such as contact closures and automation control.
Rack Mounting
The X1 is designed to be mounted into an industry standard 19” equipment rack and
requires three rack units (5.25 inches / 13.335cm) of vertical space. If using only two rack
screws always use the bottom two screws to prevent twisting of the front panel and other
undue forces from harming the processor chassis.
The X1 does not need nor does it have top or bottom cover ventilation holes. Cooling
is accomplished via cooler air drawn into vertical slots positioned lower in the side panels
which allows latent heat rising by natural convection to exit slots in the top of the rear panel.
Asmall fan is located inside the unit which stirs the air to even out the internal temperature.
This fan has an 80,000 hour rated minimum lifetime and has no role in “removing” heat.
In the unlikely event that the fan fails, its failure will not compromise the operation of the
X1 as long as the unit is being operated in a reasonable environment (below 104F or 40C).
The X1 may be mounted between other devices in the equipment rack; however, in
accordance with good engineering practice it should not be mounted directly above devices
that generate a signicant amount of heat (such as power ampliers or power supplies).
If such a location is unavoidable, then it is advisable to utilize an extra 1RU blank rack
panel between the X1 and devices immediately above and/or below it.
WARNING!
With very few exceptions, the X1 chassis does not need to be opened
in the eld.
Please be advised that the unit contains high voltage power supply
circuits operating at voltages well above AC line potential.
These voltages are not only hazardous but also potentially deadly if
accidentally contacted.
There are no user-serviceable parts inside the unit and it should
be returned to Wheatstone Corporation under a Return Authorization
should repair ever become necessary.
page 1 – 5
AirAura X1 / Dec 2016
GENERAL INFORMATION
X1 Installation Tips
Grounding
Establish a low impedance common ground in the facility and try to route all equip‑
ment grounds to that point, using conductors with the largest possible surface area while
keeping those leads as short as possible. The X1’s ground reference (its chassis) should
be connected to the station ground. Such a connection is especially important when the
X1 is operated in a high RF environment because it helps minimize differential voltages
between the processor’s chassis and other pieces of equipment.
Surge Protection
Always place surge protection circuits as close as possible to the device being protected.
AC power line surges should be handled in a way that keeps instantaneous potential dif‑
ferences between the power line hot, neutral, AC grounding conductor, the station ground
and the processor chassis as low as possible. Likewise, measures should also be taken
to keep the instantaneous potential difference between the audio cable shields and the
processor chassis as low as possible (this applies to all audio equipment, not just the X1),
particularly when the equipment is located within the electrically hostile environment of
a station’s transmitter facility.
UPS/Power Conditioning
Choose the best power conditioning/UPS units that your budget will allow, focusing
on the most important features and options that you actually need. Some questions to ask
while reviewing features are:
- How does the unit handle AC power that is not exactly 60Hz, such as when the facil‑
ity is on its backup generator?
‑ If the unit has onboard surge protection, what kind of surge capability does it have
and where are those surges directed to?
‑ Is the unit equipped with remote monitoring capability?
‑ Does it have onboard monitoring and alarms to signal problems such as batteries
with low reserve?
Analog Audio Input Connections
Balanced audio input sources should be connected to the X1 using standard two‑con‑
ductor shielded audio cable such as Belden 8451 or 9451.
Unbalanced input audio connections should
be made with shielded two conductor cable.
At the unbalanced source’s output connect
its “+” output to the X1’s “Hi” input (XLR
Pin
2) and connect the shield wire to X1’s
“Lo” input (XLR Pin 3). If the cable’s shield
is used (recommended) connect it at the X1 end only (XLR Pin 1) to prevent AC ground
loops.
page 1 – 6
AirAura X1 / Dec 2016
GENERAL INFORMATION
If RF interference is an issue, the far (oating
and ungrounded) end of the cable shield can
be experimentally bypassed to RF ground via
a 0.01uF, 250V AC rated capacitor. Suitable
capacitors are:
TDK CS17-F2GA103MYGS
Murata DE2F3KH103MA3B
Panasonic ECK-ATS103MF
AVX 65N103MBLCP
Analog Audio Output Connections
Balanced audio loads should be connected to the X1’s outputs using standard two‑con‑
ductor shielded audio cable. Unbalanced audio loads should be avoided, but if they can’t
they should be connected using shielded two conductor cable such as Belden 8451 or
9451 (as if connecting a balanced source).
The X1 is equipped with an active balanced output stages that behave like a transformer.
Because of this behavior the wiring may be different than expected.
The unbalanced load’s “Hi” lead should be connected to XLR connector Pin 2 (“Hi”).
The unbalanced load’s shield should be con‑
nected to the X1’s output XLR Pin 3 (“Lo”).
Then, and to enable the X1’s balanced output
amplier to operate correctly when driving
the unbalanced load, it is recommended that
the X1’s XLR output Pin 1 (ground/shield)
also be connected to Pin 3 (“Lo”), noting that this MUST BE DONE at the X1 output
connector (see the diagram above).
Note that it is not advisable to connect Pin 1 and Pin 3 conductors together at the far
end of the cable as doing so can induce external noise and crosstalk on the output ampli‑
er’s “load sense” lead which is XLR Pin 3 when Pin 2 is being used as the “Hot.”
As in the input case, if RF interference is an
issue the far (oating) end of the cable shield
can be experimentally bypassed to RF ground
through a 0.01uF 250V AC rated capacitor
to see if it helps. Please refer to the listing
above for capacitors known to be effective
in this task.
Digital Audio Connections
For digital audio connections always use a good quality digital audio cable (or twisted
pair Category 5E/6 Network cable) having a characteristic impedance of 110 ohms. This
cable should be shielded where possible, and in the case of multi‑pair cable, each pair
should be individually shielded. Foil shielding is recommended for permanent installa‑
tions, and a cable with foil shield plus an overall braid should be used in applications
where frequent exing of cables might occur.
page 1 – 7
AirAura X1 / Dec 2016
GENERAL INFORMATION
Generic “audio” cable such as Belden 8451 and 9451 may sometimes be used for in‑
terconnecting AES3 digital audio devices as long as the cable is short. The actual cable
length that will work satisfactorily is determined by many factors and may include the error
correction and jitter tolerance of the AES3 receiver, the characteristics of the digital cable
driver, and the characteristics of the specic cable being used and its length. “Generic”
analog audio cables typically has much higher capacitance than digital cable, which can
slow down the rise time of digital data signals impairing the ability of the AES3 receiver
to accurately recover the digital signal without errors. This can result in increased jitter,
dropouts, or at the extreme, no audio at all.
Where to Install the X1
The best location to install the X1 is at the transmitter site. This requires that a discrete
Left/Right STL, either analog or digital, be involved in the signal path. The major benet
of a transmitter site installation is that it enables the use of the X1’s built‑in lab‑grade
stereo encoder which allows much tighter control of modulation peaks.
A transmitter site location for the processor has the additional benet of allowing the use
of the X1’s highly oversampled composite processor for an additional loudness advantage.
The Wheatstone composite clipper algorithm is much cleaner and more forgiving than
those in other products, and in combination with the X1’s tight pilot and SCA protection
lters can create additional loudness without the audible grunge that traditional composite
clipper designs typically create.
We recommend that whenever there is a choice between using the AES output of the
processor or the composite output to feed your exciter that the composite output should
be chosen to maximize loudness, peak control and reap the benet of the purpose built
stereo generator in the processor over the “add on” stereo generator in the exciter. While
the exciter’s AES3 digital input may be “clean” and it may be “digital”, it also precludes
the ability to gain additional loudness through the use of X1’s intelligent oversampled
composite clipper. Also, depending on factors including the sample rates being used the
exciter’s AES digital input can exhibit inferior peak control compared to the exciter’s
composite input.
When X1 is located at the studio and an STL is being used to send the program mate‑
rial to the transmitter site there are several issues to consider:
Digital STL
There are two categories of Digital STL’s on the market – those with codec‑based
audio compression and those using uncompressed linear audio.
When the digital STL employing codec‑based audio compression is being used, X1
should be located at the transmitter site which places it after the codec. The reason for
this is that most codecs will sound better when presented with unprocessed studio audio
instead of highly processed and pre‑emphasized audio from the processor’s output. Further,
the encoding schemes used in such STL’s cannot accurately pass the well-dened peak
levels created by X1 which can create a modulation (loudness) disadvantage.
Installing X1 at the studio end of a “compressed” STL brings with it at least two caveats:
‑ The stereo generator and composite clipper inside X1 will not be available. Many
digital exciters offer stereo generator and composite clipper functions, but their
clippers have historically been quite crude compared to X1’s exceptional clipper.
page 1 – 8
AirAura X1 / Dec 2016
GENERAL INFORMATION
Therefore, “exciter‑hosted” composite clippers are not the optimum choice when the
station’s ultimate sound quality is important.
‑ Compressed STL’s do not perform well when presented with competitively processed
audio, especially when that audio is pre‑emphasized. The reason for this is because
codecs do their work by examining the audio for opportunities to remove content
that shouldn’t be audible to the average human ear. When densely processed audio
is presented to a codec there are fewer “opportunities” for it to remove redundant
audio information and most importantly, then mask that removal from our hear‑
ing so that we don’t notice it. When handling heavily processed (limited dynamic
range) material, codec operation is usually much more obvious – even to the point
of being objectionable – than when the processing is located after the codec where
the “masked” artifacts are only occasionally and, usually, minimally unmasked by
“processing gain”.
Uncompressed (linear) digital STL’s have only one major limitation – placing
X1 at the studio end of the STL will preclude the use of X1’s stereo generator and com‑
posite clipper.
TIP: If using X1 at the studio be certain that any clippers in the stereo generator at the
transmitter site are properly set up to complement the settings in X1. This will prevent
gross distortion and potentially large modulation overshoots.
Pre‑emphasis should always be applied by the audio processing, not the exciter. Modern
FM audio processors have highly sophisticated technology to deal with the challenges
presented by FM pre‑emphasis curve and can provide very tight modulation control with
very low perceived distortion. FM exciters do not have this technology.
The best location for the audio processor from an overall performance standpoint is
always at the transmitter.
Analog Left/Right STL
Older analog discrete left/right STL’s can suffer from an inability to control audio peaks
because of inadequate bandwidth in their IF circuits and/or poor low frequency and phase
performance. Individual left/right STL’s rarely have identical group delay and this will
adversely affect stereo separation when the signal is nally converted to the multiplex
composite domain. Such STL’s can also suffer from AFC bounce when handling highly
processed low frequency material and this can rob modulation capability and therefore
reduce on‑air loudness.
Composite Analog STL
A high quality analog composite STL can advantages over an analog left/right STL
and typically have broader audio bandwidth and better audio performance than analog
discrete STL’s. Most even have the capability to also piggyback subcarriers such as SCA
and RDS along with the composite audio. This means that most SCA and RDS generators
may also be located at the studio end of the STL, which, along with the audio processor,
makes for a very convenient setup. With a modern composite STL and properly engineered
point‑to‑point path, the audio can be nearly as transparent as a digital STL.
page 1 – 9
AirAura X1 / Dec 2016
GENERAL INFORMATION
Analog Phone Lines
Discrete left/right analog “phone line” STL’s are not recommended because of the
inability of most Telco service providers to meet the at frequency response and phase
matching requirements of the pair of audio circuits. Furthermore, in many countries wide‑
band analog circuits have become unavailable or their cost is prohibitive. On the other
hand if the “wired” STL is a dedicated (and equalized if necessary) pair of circuits that
is under the station’s full control it may be acceptable.
Arbitron People Meter (PPM)™
Field experience has been that Wheatstone processing algorithms favorably pass the
data watermarking scheme used in the Arbitron People Meter rating service technology,
regardless of the aggressiveness of the processing being performed. The X1 algorithms
are no exception. The X1 hardware also adds the additional benet of inserting the PPM
watermark and associated hardware towards the back of the processing for both the HD
and FM audio paths. This eliminates the need of having an external AGC to feed consis‑
tent audio to the PPM encoder. You can now use the internal AGC in the X1 to do this
while allowing the PPM encoder to insert the watermark AFTER most of the processing.
AC Power Considerations
Please note that in order to enhance its long‑term reliability X1 has no power switch
(switches usually become intermittent over time without regular use).
X1 accepts AC line input voltages between 90 and 260 VAC, 50 or 60Hz. Power
consumption is under 100VA.
Although aggressive AC input ltering is utilized on the AC power input it is always
advisable to use external surge protection and an uninterruptible power supply (UPS)
wherever possible, especially where the AC power quality can be in question, such as at
a remote transmitter site.
Power conditioning, surge suppression, and even power backup devices are wise
investments when using sensitive modern electronic devices. X1 is, after all, a highly
specialized “computer.”
The use of a UPS (uninterruptible power supply) is usually recommended and will
protect X1 from short duration power interruptions and glitches which might otherwise
signal it to reboot. When X1 reboots there will be a loss of audio for approximately 15
seconds.
page 1 – 10
AirAura X1 / Dec 2016
GENERAL INFORMATION
Rear Panel Connections
The image below shows the rear panel of the X1 and the location of various connectors
associated with an installation:
AirAura X1’s rear panel connectors from left to right are:
Bottom Row Top Row
Analog Left Channel In SCA‑1 Input
Analog Right Channel In SCA‑2 Input
AES Insert Loop Output (Send) TX 1 Out
AES Insert Loop Input (Return) TX 2 Out
FM/HD Analog Left Channel Out GPO Status Output
FM/HD Analog Right Channel Out
AES Digital Input
FM AES Digital Out (L/R or baseband192)
HD AES Digital Out
GPI Input
Ethernet/WheatNet-IP Interface
IEC Standard male AC Power Input
The listed connections are made via various connectors mounted on the X1’s rear panel.
• Nine XLR connectors are provided for analog and digital audio input and output
connections, plus an insert loop for ratings encoders.
• Four BNC connectors are provided for SCA inputs and TX (transmitter) out, or
Composite Multiplex (MPX) connections.
• One RJ-45 connector is provided for Ethernet connections. This connector may
be used to interface X1 to a WheatNet‑IP audio network or to connect it to a Win‑
dows®PC running the Wheatstone X1 GUI.
• Two DB-9 connectors provide 8 GPI inputs (for selecting presets in the rst eight
storage slots) and four pre‑assigned GPO outputs.
The pinout drawings on pages 1-17 through 1-20 summarize wiring connections.
Table of contents
Other Wheatstone Corporation Processor manuals
