Avid Technology HD OMNI User manual

HD OMNI Guide

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Contents iii
Chapter 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
HD OMNI Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
What’s Included. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
System Requirements and Compatibility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Registration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
About This Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
About www.avid.com . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Chapter 2. HD OMNI Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
HD OMNI Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
HD OMNI Back Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Chapter 3. Connecting HD OMNI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Connecting HD OMNI to an HD Native Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Connecting HD OMNI to Pro Tools|HD Cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Example Studio Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Chapter 4. Configuring HD OMNI in Pro Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Pro Tools Hardware Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Pro Tools I/O Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Chapter 5. SETUP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
SETUP Mode Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Analog Output (OUTLVL). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Analog Output Trim (OUTRIM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
TRS Output Mirrors (TRSOUT). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Fold Down (FOLDWN). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Analog Line Input Reference Level (IN REF). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Limiter (LIMITR). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Internal Sample Rate (SRATE). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Clock Source (CLOCK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Contents

HD OMNI Guideiv
Digital 1–2 Input Source (DIG1–2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Sample Rate Conversion (SRC1–2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
SPL Display Calibration (SPLCAL). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Fan Control (FAN). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Firmware Version (VER) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Factory Reset (RESET). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Display Contrast (CNTRST). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Chapter 6. Pinout Diagrams for the DB-25 Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Analog Output DB-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
AES/EBU DB-25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Chapter 7. Sound Pressure Level Display Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Appendix A. Compliance Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Environmental Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
EMC (Electromagnetic Compliance). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Safety Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Chapter 1: Introduction 1
Chapter 1: Introduction
Avid®HD OMNI is a professional digital audio
interface designed for use with Avid HD Native
and Pro Tools|HD hardware. HD OMNI provides
a compact preamp, input mixer, monitoring,
and I/O solution for music production and re-
cording, and post production studios.
HD OMNI Features
Analog I/O
• 24-bit analog-to-digital (A/D) and digital-to-
analog (D/A) converters, with support for
sample rates up to 192 kHz
• 2 high-quality Mic/DI preamps (Channels
1–2)
• 2 combined XLR and 1/4-inch TRS front panel
inputs for microphone and instrument level
input
• 2 XLR back panel microphone inputs
• 2 1/4-inch TRS Send and 2 1/4-inch TRS Re-
turn back panel jacks for hardware inserts on
channels 1 and 2
• 4 analog TRS line level back panel inputs
(Channels 1–4)
• Soft Clip and Curv limiting circuits to protect
against clipping on analog input
• 8 channels of analog back panel output using a
DB-25 breakout cable (sold separately) with
variable output gain
• 2 channels of analog back panel output using
TRS (Mirrors channels 1–2 or 7–8 on DB-25
connector)
• Front panel stereo 1/4-inch headphone jack
Digital I/O
• 8 channels of AES/EBU output (up to 192 kHz
Single Wire) using a DB-25 breakout cable
(sold separately)
• 2 channels of AES/EBU XLR input (up to
192 kHz Single Wire)
• 2 channels of S/PDIF RCA input and output
(up to 192 kHz)
• 8 channels of ADAT TOSLINK input and out-
put
• Support for ADAT S/MUX Optical for sample
rates of 88.2 kHz, 96 kHz, 176.4 kHz, and
192 kHz
• Support for two channels of S/PDIF Optical
with sample rates of up to 96 kHz
• Real-time sample rate conversion (SRC) on
Digital Inputs 1–2 of either AES/EBU, S/PDIF,
or Optical (S/PDIF)
HD OMNI provides multiple analog input
connections, but only provides up to four
channels of simultaneous analog input for
Pro Tools.
SRC is not supported with ADAT S/MUX.

HD OMNI Guide2
Monitoring
• An additional stereo “CUE” output path in
Pro Tools®for headphone monitoring from the
front panel headphone jack
• Front panel Control Room (MAIN/ALT) and
Headphone monitoring volume control
• Flexible monitoring with fold-down from all
stereo and surround formats (up to 7.1 sur-
round)
• Input mixer for low latency direct monitoring
of a variety of incoming signals (configured in
the Pro Tools Hardware Setup)
Synchronization
• Loop Sync input and output for connecting
additional Pro Tools|HD interfaces and
peripherals
• External Clock input and output for synchro-
nizing HD OMNI with external Word Clock
devices
What’s Included
•HDOMNIaudiointerface
•ACpowercable
• DigiLink Mini cable (18 inches [0.46m])
• DigiLink Mini adapter
• BNC cable (18 inches [0.46m])
•HDOMNIGuide
•HealthandSafetyGuide
• Registration Information Card
System Requirements and
Compatibility
Avid can only assure compatibility and provide
support for hardware and software it has tested
and approved.
For complete system requirements and a list of
qualified computers, operating systems, hard
drives, and third-party devices, visit:
www.avid.com/compatibility
Registration
Review the enclosed Registration Information
Card and follow the instructions on it to quickly
register your purchase online. By registering,
you become eligible to receive the following:
• Technical support information
• Software update and upgrade notices
• Hardware warranty information
Hardware Warranty
Your warranty can be found on the Registration
Information Card.

Chapter 1: Introduction 3
About This Guide
This guide provides a basic overview of the
HD OMNI features and functionality.
For hardware installation instructions for your
HD Native hardware, see the HD Native Install
Guide.
For hardware installation instructions for your
Pro Tools|HD hardware, see the Pro Tools|HD
User Guide.
For Pro Tools installation instructions, see the
Pro Tools Installation Guide.
For additional information about using
Pro Tools software, see the Pro Tools Reference
Guide (in Pro Tools, choose Help > Pro Tools
Reference Guide).
Conventions Used in This Guide
All of our guides use the following conventions
to indicate menu choices and key commands:
:
The names of Commands, Options, and Settings
that appear on-screen are in a different font.
The following symbols are used to highlight
important information:
Convention Action
File > Save Choose Save from the
File menu
Control+N Hold down the Control key
and press the N key
Control-click Hold down the Control key
and click the mouse button
Right-click Click with the right
mouse button
User Tips are helpful hints for getting the
most from your system.
Important Notices include information that
could affect your data or the performance of
your system.
Shortcuts show you useful keyboard or
mouse shortcuts.
Cross References point to related sections in
this guide and other Pro Tools guides.

HD OMNI Guide4
About www.avid.com
The Avid website (www.avid.com) is your best
online source for information to help you get the
most out of your Pro Tools system. The follow-
ing are just a few of the services and features
available.
Product Registration Register your purchase
online.
Support and Downloads Contact Avid Customer
Success (technical support); download software
updates and the latest online manuals; browse
the Compatibility documents for system re-
quirements; search the online Knowledge Base
or join the worldwide Pro Tools community on
the User Conference.
Training and Education Study on your own using
courses available online or find out how you can
learn in a classroom setting at a certified
Pro Tools training center.
Products and Developers Learn about Avid
products; download demo software or learn
about our Development Partners and their plug-
ins, applications, and hardware.
News and Events Get the latest news from Avid
or sign up for a Pro Tools demo.

Chapter 2: HD OMNI Overview 5
Chapter 2: HD OMNI Overview
This chapter provides an overview of the front and back panel features of HD OMNI.
HD OMNI Front Panel
Power Switch and LED Ring
This button turns HD OMNI on and off.
When powering on HD OMNI, the LED ring
around the power button lights amber, flashes
green, and then turns back to amber.
The LED ring is amber when the unit has power,
unless Pro Tools is running. The LED lights
green only when Pro Tools is running.
CH1 and CH2 Inputs
The front panel Channel 1 (CH1) and Channel 2
(CH2) Inputs provide combined XLR and
1/4-inch TRS inputs for microphone and instru-
ment level input. Use XLR for microphone con-
nections and use 1/4-inch for instrument con-
nections.
HD OMNI Front Panel
When power cycling HD OMNI, wait at least
15 seconds before turning HD OMNI on
again after turning it off. Failure to do so
may result in losing the current Preamp
Gain Levels and other settings.

HD OMNI Guide6
Preamp Controls
The front panel Channel 1 and 2 inputs provide
high-quality Microphone and Instrument level
preamps. These two preamp channels can be
linked so that changing any parameter on either
channel causes an identical change to the other
preamp channel (this is useful for stereo
sources). When unlinked, the parameters for
each preamp can be set independently.
Input Type Lets you select MIC, LINE, or INST
for input on Channels 1 and 2. The correspond-
ing LED lights to indicate which option is se-
lected.
When MIC is selected, the back panel MICRO-
PHONE inputs are used for channel 1 and 2 in-
put, unless an XLR cable is connected to the
front panel CH1 or CH2 inputs, then the front
panel connection is used. Remove the XLR cable
from the front panel connector to regain use of
the rear panel MIC connection.
When LINE is selected, the back panel LINE IN 1
and 2 1/4-inch TRS inputs are used.
When INST is selected, the front panel 1/4-inch
TRS inputs are used.
When Link 1 & 2 is disabled, the Input Type can
be independently enabled (or disabled) on
Channels 1 and 2 by pressing the PREAMP En-
coder to select the desired channel.
PAD Enables (or disables) a –20 dB pad for both
Channel 1 and Channel 2 inputs. The PAD but-
ton LED lights when the pad is enabled.
When Link 1 & 2 is disabled, PAD can be inde-
pendently enabled (or disabled) on Channels 1
and 2 by pressing the PREAMP Encoder to select
the desired channel.
48V Enables (or disables) 48V phantom power
for the Channel 1 and Channel 2 XLR inputs.
The 48V button LED lights when the phantom
power is enabled. You can manually enable or
disable the 48V option only when the Input Type
is set to MIC. When switching to another Input
Type (such as LINE), phantom power continues
to be supplied to the MIC channel.
When Link 1 & 2 is disabled, 48V can be inde-
pendently enabled (or disabled) on Channels 1
and 2 by pressing the PREAMP Encoder to select
the desired channel.
CH 1 and CH 2 MIC/LINE/DI Inputs, and Preamp
controls
When the Input Type is set to LINE, the
PREAMP is bypassed. Also, the preamps for
the MIC/INST inputs do not change level
when LINE is selected, so you can easily re-
vert back to MIC or INST input.
When using the INST input with some
instruments (such as a guitar or bass),
you may want to engage the Pad to avoid
clipping on input.
Inserting or removing an XLR cable to or
from the front panel inputs automatically
disables phantom power (if it is on).

Chapter 2: HD OMNI Overview 7
High Pass Filter Enables (or disables) a
12 dB/octave high-pass filter with a roll-off
starting at 85 Hz for the Channel 1 and Channel
2 inputs. The High Pass Filter button LED lights
when the high-pass filter is enabled. This option
is not available when the Input Type is set to
LINE.
When Link 1 & 2 is disabled, the High Pass Filter
can be independently enabled (or disabled) on
Channels 1 and 2 by pressing the PREAMP En-
coder to select the desired channel.
Phase Invert Inverts the phase for the Channel 1
and Channel 2 front panel inputs. The Phase In-
vert button LED lights when this option is en-
abled.
When Link 1 & 2 is disabled, Phase Invert can be
independently enabled (or disabled) on Chan-
nels 1 and 2 by pressing the PREAMP Encoder to
select the desired channel.
PREAMP Display Shows the gain value (+10 to
+65 dB).
When Link 1 & 2 is disabled, gain boost or atten-
uation for either Channel 1 (P1) or Channel 2
(P2) can be independently adjusted by pressing
the PREAMP Encoder to select the desired chan-
nel.
PREAMP Encoder Lets you adjust the input gain
for MIC and INST inputs (by rotating the en-
coder), and toggle front panel controls between
the two preamp channels (by pressing). Press
the encoder to toggle between P1 and P2 (Chan-
nel and Channel 2). Turn the encoder clockwise
to increase and counterclockwise to decrease the
input gain for the selected channel (from +10 to
+65 dB). Gain can be adjusted in 1 dB incre-
ments.
LINK 1 & 2 Links (or unlinks) controls for the
Channel 1 and Channel 2 front panel inputs. The
Link 1 & 2 button LED lights when this option is
enabled. If the two channels are linked, when
levels between channels 1 and 2 are different,
the difference is maintained when changed the
levels until an upper or lower limit (+10 or +65)
is reached. When the upper or lower limit is
reached by one of the channels, you can con-
tinue to adjust the level of the other channel un-
til the limit is reached, but the difference be-
tween the two channels is no longer maintained.
INSERT Enables (or disables) the returns for any
hardware inserts connected to the back panel
Channel 1 and Channel 2 input and output pairs.
Note that the sends are always active.
When Link 1 & 2 is disabled, INSERT can be in-
dependently enabled (or disabled) on Channels
1 and 2 by pressing the PREAMP Encoder to se-
lect the desired channel.
Preamp Signal Path
The Channel 1 and Channel 2 front panel inputs
use the following signal path:
Input Signal > Pad > Preamp > HPF > Insert >
Limiter > ADC > Phase Invert

HD OMNI Guide8
Synchronization and Sample
Rate LEDs
Sync Mode LEDs
The SYNC MODE LEDs indicate the current
Clock Source as set in the Pro Tools Hardware
Setup (see “Pro Tools Hardware Setup” on
page 25) or on HD OMNI in SETUP mode (see
“Clock Source (CLOCK)” on page 50).
INT (Internal) Indicates the HD OMNI sample
clock is generated by its internal crystal oscilla-
tor, as determined by the session Sample Rate.
EXT (External) Indicates that the HD OMNI is ei-
ther using the EXT CLOCK IN port or a digital
source for system synchronization.
When synchronized to Word Clock, External
Clock input and output do not have to be at the
Word clock rate. At 44.1 kHz and 48 kHz, EXT
CLOCK IN synchronization will be 1x the cur-
rent session sample rate. However, for sample
rates higher than 48 kHz, HD OMNI generates a
choice of 1x, 2x, or 4x of a base rate of 44.1 kHz
or 48 kHz, as follows:
Synchronization and Sample Rate LEDs
Session Sample Rate Word Clock Support
44.1 kHz 44.1 kHz
48 kHz 48 kHz
88.2 kHz 88.2 kHz
44.1 kHz
96 kHz 96 kHz
48 kHz
176.4 kHz 176.4 kHz
44.1 kHz
192 kHz 192 kHz
48 kHz
The Word Clock base rate can only be set in
the Pro Tools Hardware Setup.
If the EXT LED flashes on and off,
HD OMNI does not have external sync.
Check to make sure that HD OMNI is receiv-
ing synchronization from the correct clock
source.

Chapter 2: HD OMNI Overview 9
LOOP Indicates that the HD OMNI is slaving to
another Avid HD audio interface or a SYNC pe-
ripheral using Loop Sync.
MST (Loop Master) Indicates which audio inter-
face is the master peripheral. The Loop Master
LED will be continuously lit on the current Loop
Master peripheral only, and unlit on all other
peripherals. (Only one Avid HD peripheral can
be Loop Master at a time.) The Loop Master LED
will always be lit with a single interface.
With HD Native hardware, Loop Master defaults
to the first audio interface connected to Di-
giLink Mini Port 1 on the HD Native card.
For Pro Tools|HD systems, Loop Master defaults
to the first audio interface connected to the pri-
mary, or “core” Pro Tools|HD card. On
Pro Tools|HD (for PCIe), this is the Accel Core
card. On Pro Tools|HD (for PCI), this is the HD
Core card.
Sample Rate LEDs
These LEDs display the current sample rate of
the HD OMNI internal crystal oscillator:
44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz,
or 192 kHz. The sample rate can be set in
Pro Tools when you create a new session, or in
the Hardware Setup (see “Pro Tools Hardware
Setup” on page 25) or Playback Engine dialogs if
no session is open. You can also set the Sample
Rate in SETUP mode if Pro Tools is not running
(see “Internal Sample Rate (SRATE)” on
page 49).
METERS
These five-segment LEDs indicate signal level
for either the input or output channels 1–8.
These meters are calibrated at –42 dB, –18 dB,
–12 dB, –6 dB, and 0 dB, respectively. The 0 dB
LED segment lights red if clipping occurs at the
Input or Output depending on whether IN or
OUT is selected.
IN/OUT Button Toggles whether the Meters show
the signal levels for either the Input or the Out-
put channels.
IN LED Indicates that the Meters are showing
the signal levels for the Input channels assigned
in the Pro Tools Hardware Setup.
OUT LED Indicates that the Meters are showing
the signal levels for the Output channels as-
signed in the Pro Tools Hardware Setup.
Input/Output Meters
The front panel METERS only display the
eight analog/digital Input or Output
channels assigned in the Pro Tools Hard-
ware Setup. Unassigned channels are not
displayed on the front panel METERS. The
output METERS only show signal level from
Pro Tools output channels. They do not
display signal levels for direct monitoring.
A signal that meters at 0 on the HD OMNI
will not necessarily clip; use the on-screen
meters in Pro Tools to determine whether a
signal is clipping.

HD OMNI Guide10
MONITOR Controls
HD OMNI provides onboard monitoring from
mono up to 7.1 surround. Use the front panel
MONITOR controls to select the monitoring
path and adjust monitoring levels. You can con-
figure the following monitoring options:
• Control Room Outputs (MAIN and ALT as
configured in Pro Tools)
•MUTE,ALT,andCUEtoHeadphones
•HeadphoneOutput
•SETUP
SETUP Enables (or exits) Setup mode. The
SETUP button LED is lit when in Setup mode
(for more information about Setup mode, see
Chapter , “SETUP Mode”).
CUE Enables (or disables) a dedicated stereo
Cue mix from Pro Tools that is sent to the head-
phones. The CUE button LED lights when en-
abled. When CUE is disabled, the headphones
monitor the same mix as the Control Room out-
puts (see also “CUE 1–2” on page 42).
ALT Toggles the Control Room output paths be-
tween MAIN and ALT. The LED is lit when the
Control Room output is assigned to ALT, and it
is off when the Control Room output is assigned
to MAIN. You can also press and hold the ALT
button to engage ALT Trim mode (see “Analog
Output Trim (OUTRIM)” on page 46).
MUTE Mutes (or unmutes) the MAIN or ALT
Control Room outputs only, whichever is active.
The LED lights when MUTE is enabled.
MONITOR Encoder Lets you select and adjust the
output levels for the MAIN, ALT, and head-
phone outputs. You can also use the Monitor en-
coder to enter Trim values in ALT Trim mode
and to navigate Setup mode. Press the encoder
to switch between Control Room (CR) and
Headphone mode (HP).
In Setup mode, press the encoder to select and
confirm settings. For more information on
Setup mode, see Chapter , “SETUP Mode.”
MONITOR Display Shows which output level is
being controlled and the value for that parame-
ter:
• “CR” = Control Room level (either MAIN or
ALT)
•“HP”=Headphonelevel
Monitor controls and Headphone jack
For more information on configuring moni-
toring with HD OMNI in Pro Tools, see
“Monitor” on page 29.
When power cycling HD OMNI, MUTE is
temporarily engaged automatically to pro-
tect the monitor outputs for the Control
Room monitor paths declared in Pro Tools.
The MUTE button does not affect the Head-
phone output.

Chapter 2: HD OMNI Overview 11
HEADPHONE Jack
HD OMNI provides a single stereo 1/4-inch
headphone jack on the front panel. The output
to the headphone jack can either mirror the ste-
reo channels of the selected Control Room mon-
itoring path or the dedicated CUE 1–2 output
from Pro Tools (see “CUE 1–2” on page 42).
Use the MONITOR Encoder to control the Head-
phone level (see“MONITOR Controls” on
page 10).
The HD OMNI Headphone output also lets you
monitor greater than stereo format sessions, in
two different ways: passing the Left and Right
channels only, or folding down from the
greater-than-stereo format to stereo. For exam-
ple, with a 5.1 monitor format, if fold down is
not enabled, only the Left and Right channels
will be heard in the headphones. However, with
fold down enabled, all channels will be folded
down to stereo for headphone monitoring.
You can configure multichannel monitoring and
enable (or disable) fold down or headphone
monitoring in the Pro Tools Hardware Setup di-
alog (for more information, see “Monitor” on
page 29).
The HD OMNI Headphone output is set to
power 600 Ohm headphones at +3 dBV.

HD OMNI Guide12
HD OMNI Back Panel
Analog Inputs
HD OMNI provides up to four channels of simul-
taneous analog inputs to Pro Tools using 24-bit
A/D converters that support sample rates up to
192 kHz. Channels 1 and 2 can be from the front
panel inputs (XLR microphone or 1/4-inch TRS
Instrument), from the back panel MICRO-
PHONE (XLR) 1 and 2 Inputs, or from the back
panel LINE IN (1/4-inch TRS) 1 and 2 Inputs.
Channels 3 and 4 are always from the back panel
LINE IN 3 and 4 Inputs.
MICROPHONE 1 and 2 Inputs
HD OMNI provides two microphone inputs
(XLR) on the back panel. These two inputs are
routed through the preamps, which can be con-
trolled from the front panel.
MICROPHONE 1 and 2 can be used for input
when the Input Type is set to MIC on the front
panel. If the Input Type is set to MIC on the
front panel, and a microphone connection is
made on the front panel Channel 1 or 2 inputs,
the corresponding back panel input is bypassed.
SEND and RTN 1 and 2
HD OMNI provides two discrete hardware sends
and returns. The selected inputs (MIC, LINE, or
INST) on Channels 1 and 2 can be routed
through the hardware sends and returns avail-
able on the back panel. This lets you use your fa-
vorite outboard gear (such as compressors or
EQs) at the signal input stage, after the pad, pre-
amp, and high-pass filter, but before the Soft
Clip or Curv limiter circuits and the analog-to-
digital converter.
Send and Return 1 inserts on Channel 1 and
Send and Return 2 inserts on Channel 2. Select
(or deselect) INSERT on the front panel to en-
able (or disable) the hardware inserts. Note that
the sends are always active.
LINE IN 1–4
HD OMNI provides four line level 1/4-inch TRS
inputs. LINE IN 1 and 2 can only be used for in-
put when the Input Type is set to LINE on the
front panel.
HD OMNI Back Panel
Back panel analog inputs

Chapter 2: HD OMNI Overview 13
Analog Outputs
TRS OUT 1 and 2
HD OMNI provides two 1/4-inch TRS Outputs
for monitoring either ANALOG OUT 1 and 2 or
ANALOG OUT 7 and 8 (or neither). This can be
set in Pro Tools on the Analog Out tab of the
Hardware Setup dialog (see “Analog Out” on
page 28) or on HD OMNI in SETUP mode (see
“TRS Output Mirrors (TRSOUT)” on page 47)
ANALOG OUT 1–8
HD OMNI provides a DB-25 connector for eight
channels of analog audio output. These balanced
outputs operate at +10 dBu (Speaker level) or at
+24 dBu (Line level). You can set the output
level in Pro Tools on the Analog Out page of the
Hardware Setup dialog (see “Analog Out” on
page 28).
Digital Inputs and Outputs
AES EBU OUT 1–8
HD OMNI provides one DB–25 connector for
eight channels of AES/EBU output. Each of the
paired channels is a balanced three-conductor
signal, and supports 192 kHz sample rates in
Single Wire mode.
AES/EBU INPUT
HD OMNI provides a single stereo AES/EBU
(XLR) input. The AES/EBU Input supports sam-
ple rates up to 192 kHz using AES Single Wire.
S/PDIF IN and OUT (Coaxial)
HD OMNI provides RCA jacks for stereo S/PDIF
digital data stream input and output. S/PDIF
supports up to 24-bit audio, at sample rates up
to 192 kHz.
Back panel analog TRS outputs, and analog and
digital (AES/EBU) DB-25 outputs
For a pinout diagram for the analog DB-25
connector, see Chapter , “Pinout Diagrams
for the DB-25 Connectors.”
Back panel digital inputs and outputs
For a pinout diagram for the AES/EBU DB-
25 connector, see Chapter , “Pinout Dia-
grams for the DB-25 Connectors.”
To maintain data integrity and minimize
jitter, use only 75-ohm coaxial cable for
S/PDIF connections.

HD OMNI Guide14
OPTICAL IN and OUT (1 and 2)
HD OMNI provides two sets of eight-channel
Optical (TOSLINK) input and output. The Opti-
cal I/O on HD OMNI supports up to 24-bit au-
dio, at sample rates up to 192 kHz. The number
of available Optical input and output channels
varies with sample rate as described below:
ADAT Optical
At sample rates of 44.1 kHz and 48 kHz, Optical
Port A provides eight channels of audio input
and output. Optical Port B is unused for input,
but on output it mirrors Optical Port A (chan-
nels 1–8).
S/MUX 2
At sample rates of 88.2 kHz and 96 kHz
(S/MUX 2), each Optical port provides four
channels of audio. Optical In and Out 1 send and
receive channels 1–4, and Optical In and Out 2
send and receive channels 5–8.
S/MUX 4
At sample rates of 176.4 kHz and 192 kHz
(S/MUX 4), each Optical port provides two
channels of audio. Optical In and Out 1 send and
receive channels 1 and 2, and Optical In and Out
2 send and receive channels 3 and 4.
Optical (S/PDIF)
Either set of Optical I/O ports can also be used
for two-channel Optical S/PDIF input and out-
put with support for sample rates up to 96 kHz.
HD OMNI can receive two channels of Optical
S/PDIF when operating at sample rates of 176.4
and 192kHz, but sample rate conversion (SRC)
is automatically enabled for this feature. The
Optical (S/PDIF) option can be selected in the
Pro Tools Hardware Setup dialog.
About Lightpipe-Compatible Devices
Lightpipe is an industry standard, eight-channel
optical digital audio connection created by Ale-
sis. Lightpipe is found on many devices, includ-
ing Optical (ADAT) decks, modular digital mul-
titracks (MDMs), sound cards, A/D or D/A
converters, and digital mixing consoles.
DigiLink Mini Ports
PRIMARY PORT
Use the PRIMARY PORT to connect HD OMNI
to an HD Native cards using a DigiLink Mini ca-
ble, or to a Pro Tools|HD card using a DigiLink
cable with a DigiLink Mini adapter.
The Primary port sends and receives 32 chan-
nels to and from an HD Native or Pro Tools|HD
card. Input and output channels 17–32 (if ac-
tive) are passed through to the EXPANSION
PORT. However, note that HD OMNI only pro-
vides up to eight channels of input and output.
When using HD OMNI in a system with multiple
interfaces, it provides up to eight channels of in-
put and output on Pro Tools channels 1–8 or
17–24 depending on whether or not HD OMNI is
connected directly to an HD Native or
Pro Tools|HD card, or whether it is connected to
the Expansion port of another Avid HD periph-
eral (such as an HD I/O).
When using S/MUX, only the first optical
port can be used to synchronize to external
clock.

Chapter 2: HD OMNI Overview 15
EXPANSION PORT
The EXPANSION PORT lets you connect an ad-
ditional Avid HD audio interface to HD OMNI.
The EXPANSION PORT passes input and output
channels 17–32 to the expansion (or secondary)
audio interface.
This port is only available when HD OMNI is
connected directly to an HD Native or
Pro Tools|HD card (it is not available when the
HD OMNI is connected to the Expansion Port on
another audio interface).
DigiLink Mini Cables and Adapters
Avid provides various cables and adapters to
connect Avid HD audio interfaces to HD Native
and Pro Tools|HD cards.
DigiLink Mini Cables
Use DigiLink Mini cables to connect HD OMNI
to an HD Native card, as well as to other Avid
HD audio interfaces (such as an HD I/O).
There are five different lengths of DigiLink Mini
cables:
• 18” (0.46m)
• 12’ (3.6m) (sold separately)
• 25’ (7.62m) (sold separately)
• 50’ (15.25m), the maximum length sup-
ported for 176.4 kHz and 192 kHz sessions
(sold separately)
• 100’ (30.5m), the maximum length sup-
ported by 88.2 kHz and 96 kHz sessions
(sold separately)
DigiLink Mini Adapters
Use a DigiLink cable with a DigiLink Mini
adapter to connect HD OMNI to a Pro Tools|HD
card, as well as to legacy Pro Tools|HD audio in-
terfaces (such as 192 I/O). There are two types of
DigiLink Mini adapter cables:
• 12” DigiLink male to DigiLink Mini female
•12
”DigiLink female to DigiLink Mini male
Clock and Synchronization Ports
WD CLK IN and OUT
The Word Clock I/O ports are standard BNC
connectors that receive and output word clock
signal. These ports can be used to synchronize
HD OMNI with any word clock-capable device.
Word Clock In can be selected as the Clock
Source from the front panel or in the Hardware
Setup dialog in Pro Tools. Word Clock Out can
be configured in the Hardware Setup dialog us-
ing the External Clock Output selector.
For more information about DigiLink Mini
cables and adapters, visit the Avid website
(www.avid.com).
Back panel Word Clock and Loop Sync In and Out
Because crucial timing data is passed
through the Loop Sync and Word Clock
ports, you should use high-quality, 75-ohm
RG–59 cables for making connections.

HD OMNI Guide16
LOOP SYNC In and Out
Loop Sync is a dedicated clock loop for synchro-
nizing multiple Avid HD peripherals together
(multiple audio interfaces, and/or a SYNC HD™
or SYNC I/O™ and one or more audio inter-
faces). Loop Sync uses a word clock signal based
on sample rates of either 44.1 kHz or 48 kHz. As
sample rate increases in the system, Loop Sync
continues to operate at a base rate of 44.1 kHz or
48 kHz, depending upon the higher rate.
The Loop Sync In and Out ports are standard
BNC connectors that output a 1x Word clock sig-
nal. Loop Sync should only be used to chain mul-
tiple Avid HD peripherals together (audio inter-
faces and SYNC HD or SYNC I/O).
AC Power
This connector accepts a standard AC power ca-
ble (included). HD OMNI is auto power-select-
ing (100V to 240V) and will automatically work
with a standard modular cable (IEC) to connect
to AC power outlets in any country.