Metric Halo Mobile I/O - Manual (Page 63)

2882 Users Guide
63
Output Attenuation
You may find that the 2882's analog outputs are too "hot" for your amps or powered speakers; if you
find yourself:
• Turning your amps or speakers down further than normal (barely on)
• Bringing the master fader in MIO Console or the Monitor Control level down more than a few dB
Then you are overdriving the inputs of your monitors. In this case, you should use a pad (also called an
inline attenuator) on the outputs of the 2882. You should use a pad with 20-40dB of attenuation. These
devices are available through music gear stores or online.
Copper-Based Digital Audio
2882 supports 2 channels of digital audio over copper-based connections. These connections can be made
using either S/PDIF interconnects with the RCA connectors or with AES interconnects using the XLR connectors.
Even though only one of the AES or S/PDIF inputs can be active at any given time, you can have different digital
sources connected to each of the input connectors at the same time – you use the MIO Console application to
select the active input. Audio routed to the digital outputs will be mirrored by both S/PDIF and AES outputs.
This allows you to send the same stereo pair to two devices at once.
We recommend that you use the AES interconnect mechanism to establish the digital communication between
the 2882 and other digital devices. The jitter and electrical noise tolerance on AES interconnects is substan-
tially better than with S/PDIF interconnects. The AES interconnect standard is equivalent to balanced audio
interconnections. If you need to use S/PDIF interconnects, try to use the shortest cables you can and, if possible,
use special purpose 75 ohm S/PDIF or video cables.
The RCA connectors used for S/PDIF are friction fit coaxial connectors. When you connect them, ensure that
they are fully inserted and tight.
The XLR connectors used for AES are fully locking. When connecting to them, make sure that you align the
pins and insert firmly. When you remove the connector, make sure that you release the lock by pressing the
lock release button before you pull the connector out of the 2882.
SRC
Normally, when working with digital audio transport, you must take care to ensure that all devices com-
municating with one another are synchronized to the same audio clock. While this is still an important
consideration with 2882, the hardware provides a special feature to simplify copper-based digital con-
nections to the box. The digital input on 2882 has an optional asynchronous sample rate converter (SRC)
that will automatically match the sample rate of the incoming audio to the sample rate of the 2882. This
converter is enabled by default and you can disable it in the System section of the MIO Console. If you
have synchronized the 2882 to the external source (using any of the extensive synchronization methods
provided by 2882), you will generally want to disable the SRC in order to get 24-bit transparent audio
transport over the digital input.
Optical-Based Digital Audio
Mobile I/O provides two TOSLINK™ connectors on the back panel. One is a transmit connector and the other
is a receive connector. These connectors are used with Plastic Optical Fiber (TOSLINK) cables to communi-
cate with other devices. The TOSLINK connectors can be used to communicate with either the ADAT® Opti-
cal communication protocol or the Optical SPDIF communication protocol. Each port can be independently
switched between the two protocols via MIO Console.
The ADAT Optical standard allows a device to transmit 8 channels of 24-bit audio at up to 50kHz along with
digital audio clock information.