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Digidesign
882|20 I/O Audio Interface
Installation Guide
Digidesign Inc.
3401-A Hillview Avenue
Palo Alto, CA 94304 USA
tel: 650·842·7900
fax: 650·842·7999
Technical Support (USA)
650·842·6699
650·856·4275
Product Information
650·842·6602
800·333·2137
Fax on Demand
1-888-USE-DIGI (873-3444)
World Wide Web
www.digidesign.com
Digidesign FTP Site
ftp.digidesign.com
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Copyright
This User’s Guide is copyrighted ©1999 by Digidesign, a
division of Avid Technology, Inc. (hereafter “Digidesign”), with
all rights reserved. Under copyright laws, this manual may not
be duplicated in whole or in part without the written consent of
Digidesign.
DIGIDESIGN, AVID and PRO TOOLS are trademarks or
registered trademarks of Digidesign and/or Avid Technology,
Inc. All other trademarks are the property of their respective
owners.
All features and specifications subject to change without
notice.
PN 932707755-00 REV A 11/99
Communications & Safety Regulation Information
Compliance Statement
The model 882/20 I/O complies with the following standards
regulating interference and EMC:
• FCC Part 15 Class A
• EN55103 – 1, environment E4
• EN55103 – 2, environment E4
• AS/NZS 3548 Class A
• CISPR 22 Class A
Radio and Television Interference
This equipment has been tested and found to comply with the
limits for a Class A digital device, pursuant to Part 15 of the
FCC Rules.
Communications Statement
This equipment has been tested to comply with the limits for a
Class A digital device. Changes or modifications to this product
not authorized by Digidesign, Inc., could void the Certification
and negate your authority to operate the product. This product
was tested for CISPR compliance under conditions that
included the use of peripheral devices and shielded cables and
connectors between system components. Digidesign
recommends the use of shielded cables and connectors
between system components to reduce the possibility of
causing interference to radios, television sets, and other
electronic devices.
Safety Statement
This equipment has been tested to comply with USA and
Canadian safety certification in accordance with the
specifications of UL Standards; UL813 and Canadian CSA
standard; CSA C22.2 No.1-M90. Digidesign Inc., has been
authorized to apply the appropriate UL & CUL mark on its
compliant equipment.
Important Safety Instructions
When using electric or electronic equipment, basic precautions
should always be followed, including the following:
• Read all instructions before using this equipment.
• To avoid the risk of shock, keep this equipment away from
rain water, and other moisture. Do not use this equipment
if it is wet.
• The equipment should only be connected to the correct
rating power supply as indicated on the product.
• Do not attempt to service the equipment. There are no
user-serviceable parts inside. Please refer all servicing to
authorized Digidesign personnel.
• Any attempt to service the equipment will expose you to a
risk of electric shock, and will void the manufacturer’s
warranty.
• The product should be connected only to the correct power
supply as indicated on the product.
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contents
Chapter 1. Using the 882/20 I/O
882/20 I/O Interface
882/20 I/O Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
882/20 I/O Back Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Making Signal Connections to the 882/20 I/O
Choosing between +4 dBu and –10 dBV operation modes . . . . . . . . . . . . . . . . . . . . . . . 5
Setting Up Your Studio. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Using the 882/20 I/O Interface as Stand-Alone Audio Converter
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Appendix A. Technical Specifications
A/D Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
D/A Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
. . . . . . . . . . . . . . . . . . . . . . . 6
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Contents
iii
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882/20 I/O
iv
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Using the 882/20 I/O
The 888/20 I/O™ is an 8-channel digital
audio interface which features 20-bit analog-to-digital, and 20-bit digital-to-analog
converters for superior dynamic range, reduced noise floor, and the capability to
work with the full 24-bit mixing, editing,
processing, and mastering environment of
Pro Tools.
The 882/20 I/O can be used in two ways:
As a 20-bit Audio Interface for a
◆
Pro Tools 24, or Pro Tools III-PCI system
As a stand-alone 2-channel, 20-bit audio
◆
converter
This User’s Guide explains each of the indicators and connectors on the front and
back panels of the 882/20 I/O. It also explains how to use the 888/20 I/O with a
Digidesign Pro Tools system, as well as
how to use it as a stand-alone 20-bit audio
converter in your studio.
882/20 I/O Interface
The following section explains all of the
connectors and indicators on the front and
back panels of the 882/20 I/O Interface
and how they are used.
882/20 I/O Front Panel
The 882/20 I/O has the following front
panel indicators, moving from left to right:
20
Front panel of the Digidesign 882/20 I/O
1. Power
This switch applies power to the 882/20.
The “I” position is on. The “O” position is
off.
2. Sync Mode
The Sync Mode LEDs indicate which sample rate clock reference is currently used by
the analog-to-digital converters (ADCs)
and the digital-to-analog converters
(DACs).
Using the 882/20 I/O
1
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Internal
This is the 882/20 I/O standard
setting. In this mode, the 882/20 I/O sample rate is generated by its internal crystal
oscillator (whose frequency is determined
by the Sample Rate setting in the Session
Setup window). Internal mode should be
active whenever the 882/20 I/O is not synchronized to an external clock source.
Digital
This setting indicates that a S/PDIF
word clock signal is the source for the
882/20 I/O sample rate. This is the setting
you would use for inputting material from
DAT machines or other S/PDIF digital devices.
To use the 882/20 I/O digital input and
output as an effects send and return to a
digital effects device, you should set the
882/20 I/O to Internal Sync Mode. You
should then set the digital effects device to
accept an external digital clock (from the
882/20 I/O) so it synchronizes with
Pro Tools.
In an expanded system, the system clock is
carried by the Audio Interface connected
to the first Pro Tools card in your system.
This Audio Interface will act as the master
interface in your system, and all other Audio Interfaces will be slaved to it. Only the
master interface allows you to set the Sync
Mode. Slaved interfaces do not allow this
parameter selection.
▲
Because some digital audio devices do not
output proper clock when they are not playing
back, leaving the 882/20 I/O in Digital Sync
Mode may cause Pro Tools audio playback
quality to suffer, or to play back at the wrong
pitch. If you are using digital I/O, reset the
Sync Mode from Digital to Internal after inputting material.
Slave
This LED is lit when the 882/20 I/O
sample rate is synchronized to another
Digidesign Audio Interface or synchronization peripheral. In this mode, the sample
rate of the slave interface is derived from
the frequency of the incoming master
clock signal present at the Slave Clock
(256x) port. The 882/20 I/O automatically
switches to this mode when a Slave Clock
Out signal from another Digidesign Interface, Universal Slave Driver, Video Slave
Driver, or SMPTE Slave Driver is connected
to its Slave Clock In port.
In expanded Pro Tools systems, the Super
Clock output of the master Audio Interface
locks all other interfaces together with
sample accuracy, keeping all signals
phase-synchronous.
When slaving to a Digidesign Universal
✽
Slave Driver, Video Slave Driver, or SMPTE
Slave Driver, set the clock source to Internal.
The Audio Interface will automatically switch
to Slave mode when it detects the 256x input
clock.
3. Ch 1–2 Input
This LED indicates the format (analog or
digital) of the audio input signal to channels 1 and 2. In Pro Tools, you choose analog or digital input for these two channels
in the Session Setup window. Input channels 3 through 8 of the 882/20 I/O are always analog.
882/20 I/O
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4. Sample Rate
These LEDs display the current sample rate
of the 882/20 I/O internal crystal oscillator, which can be either 44.1 kHz or 48
kHz. In Pro Tools, this is set in the Session
Setup window.
The 882/20 I/O provides the following
sample rates:
882/20 I/O Back Panel
The 882/20 I/O has the following back
panel connectors, moving from left to
right:
48 kHz
many professional audio devices. It is recommended for use with devices that cannot receive digital transfers at 44.1 kHz.
44.1 kHz
sampling rate and the Pro Tools default
sample rate. To avoid the need for sample
rate conversion, you should use this rate
when you are recording material that will
ultimately be published on a compact disc.
▲
source such as a DAT recorder, the front panel
of the 882/20 I/O indicates only the internal
oscillator sample rate, not that of the external
digital source.
This is a standard sampling rate of
This is the compact disc standard
When you are using an external digital
5. Signal Present LEDs
These LEDs indicate whether signal is
present (above the level of –30 dB) at a
given channel’s output. These LEDs indicate the presence of channel output signals, not input signals. Input signals are
monitored on-screen in the Pro Tools software. The LEDs do not indicate clipping.
Clipping is indicated by the on-screen
meters in Pro Tools software.
Back panel of the Digidesign 882/20 I/O
1. Analog Audio Inputs
These are balanced, 1/4-inch TRS jacks for
analog audio input connections. The
882/20 I/O analog inputs feature 20-bit analog-to-digital converters.
Input operating levels are switchable between +4 dBu and –10 dBV operation. Unbalanced connections are supported with
the use of standard 1/4-inch mono phone
plugs.
Because input channels 1–2 of the
882/20 I/O are software selectable between
analog or S/PDIF digital format, input to
these two analog channels is disabled
when S/PDIF digital input format is chosen
in the Pro Tools Hardware Setup dialog.
The 882/20 I/O analog inputs are factory
calibrated at a –14 dB nominal level, referenced to a full code signal. This means that
at the nominal reference input level (either
+4 dBu or –10 dBV), you have 14 dB of
headroom before clipping.
Using the 882/20 I/O
3
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2. Analog Audio Outputs
These are balanced, 1/4-inch TRS jacks for
analog audio output connections. The
882/20 I/O analog outputs feature 20-bit
digital-to-analog converters.
All eight output channels are continuously
active. Output operating levels are switchable between +4 dBu and –10 dBV operation. Unbalanced connections are supported with the use of standard 1/4-inch
mono phone plugs.
The 882/20 I/O analog outputs are factory
calibrated at a –14 dB nominal level, referenced to a full code signal. This means that
at the nominal reference output level (either +4 dBu or –10 dBV), you have 14 dB
of headroom before clipping.
3. Slave Clock In/Out
The Slave Clock Out jack is a standard BNC
type connector that outputs a 256x audio
sample rate master Super Clock signal for
slaving and synchronizing multiple
Digidesign Interfaces and synchronization
peripherals together.
The Slave Clock In jack is a standard BNC
type connector designed to receive a Slave
Clock Out signal from another Digidesign
Interface, a Universal Slave Driver
™
Slave Driver
, or SMPTE Slave Driver™ for
synchronizing multiple Digidesign Interfaces and synchronization peripherals together.
™
, Video
When the 882/20 I/O Sync Mode is set to
Internal, connecting a valid Slave Clock
Out signal to this port will cause the
882/20 I/O to automatically switch to
Slave mode. When the 882/20 I/O is the
master interface or the first interface in a
chain, Digital sync mode overrides the
Slave Clock input, and an incoming Slave
Clock Out signal will not switch the
882/20 to Slave mode.
Because crucial timing data is passed over
these ports, you should use high-quality,
75-ohm RG-59 cables for making connections, and keep total cable length to less
than 3 meters between interfaces.
4. S/PDIF Digital Input/Output
The Sony Phillips Digital Interface Format
(S/PDIF) is used in many professional and
consumer CD players and DAT recorders.
The 882/20 I/O S/PDIF jacks are unbalanced, two-conductor, phono (RCA) jacks.
Because input channels 1–2 of the
882/20 I/O are software selectable between
analog or digital format, input to these two
digital channels is disabled when analog
input is chosen in the Hardware Setup dialog in Pro Tools. Output is continuously
active on the S/PDIF output jack, even if
the 882/20 I/O input selector is set to Analog in the Hardware Setup dialog. To avoid
RF interference, use 75-ohm coaxial cable
for S/PDIF transfers and do not exceed a cable length of 10 meters.
882/20 I/O
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5. 50-pin Interface Connector
This 50-pin connector is used to connect
the 882/20 I/O to a MIX card, d24,
Disk I/O, or DSP Farm card. The necessary
cable is supplied with your Audio Interface. If you plan to connect two
882/20 I/O Interfaces to a MIX card or d24
card, a 16-channel peripheral cable
adapter is necessary. (This cable is available
from your Digidesign dealer.)
6. Power Input
This connector accepts a standard AC
power cable. The Interface is auto power
selecting (100 V–240 V), and will automatically work with a standard modular cable
to connect to AC power receptacles in any
country.
Making Signal Connections
to the 882/20 I/O
Depending on how you plan to use the
882/20 I/O, the way you connect it to your
studio will vary.
Choosing between +4 dBu and
–10 dBV operation modes
The 882/20 I/O can be set to operate at
+4 dBu or –10 dBV input and output levels. It is important that you determine
which line level mode is appropriate for
your studio. In +4 dBu operating mode,
the 882/20 I/O is a 20-bit digital audio device capable of producing audio signals at
or near +18 dBu. Check the owner’s manual for your mixer, power amplifier or effects processor to see if it can handle this
load. If it cannot, consider setting the
882/20 I/O to operate at –10 dBV line levels.
Consider the following when connecting a
mixer:
If your mixer cannot handle more than
◆
1.5V (RMS) inputs at +4 dBu, then you
should set the 882/20 I/O to operate at
–10 dBV line level.
◆
If your mixer can handle up to 6.15V
(RMS) inputs, or has pads or attenuators
on its inputs, then you can use the +4 dBu
setting on the 882/20 I/O.
Most manuals contain device input specifications, including whether or not there
are pads or attenuators. Consult the manufacturer of your mixer or power amplifier
for further information.
Using the 882/20 I/O
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Setting Up Your Studio
The following diagrams provide general
suggestions for connecting studio gear to
your system. The first illustrates a studio
setup with the 882/20 I/O connected to a
mixing console, with effects and other
gear routed into the console as well. The
second diagram shows a setup without a
mixer, where effects and monitoring gear
are connected directly to the 882/20 I/O.
S/PDIF Digital Input/Output
Inputs/Outputs 7-8
To Effects Device
S
T
U
P
T
U
O
G
O
L
A
N
A
123456
S
T
U
P
N
I
G
O
L
A
N
A
2345678
1
Analog
Audio
Effects Device
Inputs 1-6
Channel
Outputs 1-6
Instruments
Connected to Console
Tape Returns
or Inputs 1-6
A typical studio configuration with mixer
connections
Mic Preamp,
Direct Box, Synth, etc.
Analog
Audio
O
L
A
N
A
345678
2
S
T
U
P
N
I
G
Analog
Inputs/Outputs
Outputs 1-2
G
O
L
A
N
A
123456
Audio
3-8
S
T
U
P
T
U
O
Analog
Audio
Inputs 1-2
1
M
O
C
N
I
N
I
T
U
O
F
I
D
P
T
/
S
U
O
78
K
C
O
L
C
E
V
A
L
S
Analog
Audio
Outputs 1-6
S/PDIF Digital Input/Output
C
N
I
N
I
T
U
O
IF
D
T
/P
S
U
O
78
K
C
O
L
C
E
V
A
L
S
To DAT Recorder
R
E
T
U
P
Power Amp
and Speakers
To DAT Recorder
R
E
T
U
P
M
O
DAT Recorder
Effects Devices
DAT Recorder
Power Amp
and Speakers
Using the 882/20 I/O
Interface as Stand-Alone
Audio Converter
The 882/20 I/O can be used apart from
Pro Tools as a stand-alone 2-channel,
20-bit, analog-to-digital or digital-to-analog converter.
▲
The 882/20 I/O always operates at
–10 dBV when in stand-alone mode.
Before you use the 882/20 I/O in
stand-alone mode:
1
Turn off the 882/20 I/O.
2
Do not turn on your computer while the
882/20 I/O is in stand-alone mode. If you
do, the 882/20 I/O will stop functioning in
stand-alone mode.
To use the 882/20 I/O as a stand alone A/D
converter:
1
Turn off any digital devices that may
send a word clock signal to the 882/20 I/O
S/PDIF digital input.
2
Turn on the 882/20 I/O. The 882/20 I/O
searches briefly for a word clock signal on
channels 1–2 of its digital input ports.
3
If the 882/20 I/O does not detect word
clock, it functions as a stand-alone A/D
converter using its internal clock. In this
mode you will use analog inputs 1–2 and
the S/PDIF output.
Effects Devices
A typical studio configuration without a mixer
882/20 I/O
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▲
In stand-alone mode, the 882/20 only operates at a 44.1kHz sample rate. If you wish
to convert analog signals into 48kHz digital
audio, you must launch Pro Tools (or any other
software which supports the 882/20 I/O) to
change the default sample rate.
To use the 882/20 I/O as a stand alone D/A
converter:
1
Make sure that a digital device providing
a word clock signal is connected to the
S/PDIF input of the 882/20 I/O and that
the device is powered on.
2
Turn on the 882/20 I/O. The 882/20 I/O
will search for a valid word clock on its
S/PDIF input.
3
When a valid word clock lock is recognized, the 882/20 I/O will enter digital
sync mode and function as a stand-alone
D/A converter using the S/PDIF input and
analog outputs 1–2.
The 882/20 I/O sample rate is determined
by the sample rate that it detects on its
S/PDIF input.
To return the 882/20 I/O to Pro Tools-based
operation:
◆
Turn on your computer.
– or –
◆
If your computer is on, launch Pro Tools.
Using the 882/20 I/O
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882/20 I/O
8
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appendix a
Technical Specifications
General
Analog Inputs/Outputs:
Balanced/unbalanced 1/4” TRS jacks,
■
software switchable between +4 dBu and
–10 dBV line levels
Digital I/O S/PDIF:
2 channels; coaxial RCA connectors
■
Sample Rate:
■
44.1 kHz or 48 kHz, ±10ppm
Clock Reference:
■
Super Clock (256x) sample clock In/Out;
BNC connectors; additional clock references supported via Digidesign's Universal
Slave Driver, SMPTE Slave Driver, Video
Slave Driver and other optional synchronizers
Nominal Operating Level:
■
+4dBu; factory calibrated at 14dB
headroom
A/D Specifications
■
20-bit A/D converters, Delta-Sigma
SNR (signal-to-noise ratio):
≥
103dB (balanced, A-weighted)
■
■
≥
100dB (unweighted)
■
@22Hz–22kHz
THD:
0.003% @ –1dB, 1kHz; 22 Hz–22 kHz
■
Maximum Input (in +4dBu mode):
■
+18 dBu/channel or 6.15V (RMS)
Frequency Response:
■
22Hz–22kHz, ±0.5dB
Appendix A: Technical Specifications
9
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D/A Specifications
■
20-bit D/A converters, Delta-Sigma
SNR (signal-to-noise ratio):
≥ 98 dB (balanced, A-weighted)
■
■
≥ 96 dB (unweighted)
THD:
■
0.003% @ -1dB, 1kHz; 22 Hz-22 kHz
Maximum Output (in +4 dBu mode):
+18 dBu/channel or 6.15V (RMS)
■
Frequency Response:
■
22 Hz-22 kHz, ±0.5dB
Physical Specifications
Power requirements:
■
85–264 VAC, 47-63 Hz; 30 VA;
auto-switching
Weight:
■
4.8 lbs (2.2 kg)
Dimensions:
■
1U external rackmount device
19" x 1.75" x 7.5"
(48.26 cm x 4.4.5 cm x 24.77 cm)
882/20 I/O
10
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