Setup For Multiple Interfaces - MOTU UltraLite AVB User Manual

SETUP FOR MULTIPLE INTERFACES

It is possible to connect multiple MOTU interfaces
directly to your host computer through multiple
USB (and Thunderbolt) ports. Alternately, you can
connect multiple interfaces, operating as AVB
Ethernet audio interfaces, using an AVB switch
connected directly to the Mac. However, there are
several disadvantages to using any of these direct
connection schemes:
The audio interfaces will not be clocked to one
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another and may be susceptible to drift, unless you
use external word clock connections (if available).
You are better off using the AVB network
connections shown on pages 32-34. In this setup,
the interfaces are very tightly synchronized with
each other (measured in pico seconds) through
their network connections.
You will not be able to route audio directly from
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one audio interface to another. You are better off
using the AVB network connections shown on
pages 32-34, which allows you to route audio
streams (hundreds at a time) directly among
interfaces with near-zero latency.
Connecting multiple interfaces using
Thunderbolt
If you have other MOTU AVB interfaces with
Thunderbolt connectivity (1248, 8M, 16A or
112D) and your host computer has two or more
Thunderbolt ports, you can connect one interface
to each port, either directly or at the end of a
Thunderbolt daisy chain (on either port or both
ports).
Connecting multiple interfaces using
Thunderbolt and USB
Another way to operate multiple interfaces on the
same host computer is to connect the first interface
to a Thunderbolt port and the second to a USB 2.0
(or 3.0) port.
H A R D W A R E I N S T A L L A T I O N
Multiple interfaces and USB
When connected through USB, the UltraLite AVB
operates as a USB 2.0 device, even when connected
to a USB 3.0 port. USB 2.0 provides enough bus
speed for several USB 2.0 devices, but due to the
UltraLite AVB's high-performance requirements
for real-time operation and low latency timing, we
recommend the following:
Do not connect more than two units to your
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computer's USB 2.0 or 3.0 port(s).
When two units are connected with USB 2.0,
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don't connect other USB 2.0 or 3. 0 devices, such as
external hard drives.
For best results, establish clock synchronization
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with other interfaces connected to the same
computer. You can use optical or AVB to achieve
clock synchronization.
Multiple AVB Ethernet audio interfaces
When operating UltraLite AVB as an AVB Ethernet
audio interface ("AVB Ethernet audio interface
setup" on page 32), multiple AVB audio interfaces
can be connected using a MOTU AVB Switch (or
any 3rd-party AVB switch), and the Mac can see all
of them through their AVB connection. For
example, you could connect an Avid S3 console to
the Mac, and then connect a MOTU UltraLite AVB
to the S3's extra network port (which is a built-in
switch). The Mac can see both UltraLite AVB and
S3 for audio I/O. However, OS X takes over each
device for exclusive use, so they can only stream
audio to and from the Mac, not each other. The
same is true for all AVB devices connected to the
Mac. See "Syncing multiple AVB audio interfaces
connected to a Mac" on page 41.
Mixing and matching audio interfaces
You can mix and match MOTU audio interfaces.
For example, you could connect a 1248 through
Thunderbolt and another MOTU audio interface,
such as the UltraLite AVB, through USB 2.0.
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