Syncing Word Clock Devices; Connecting Multiple Motu Firewire Interfaces - MOTU 828 Mk III Hybrid User Manual

SYNCING WORD CLOCK DEVICES

The 828mk3 word clock connectors allow you to
synchronize it with a wide variety of other word
clock-equipped devices.
For standard word clock sync, you need to choose
an audio clock master (as explained in "Be sure to
choose a digital audio clock master" on page 28).
In the simplest case, you have two devices and one
is the word clock master and the other is the slave
as shown below in Figure 4-19 and Figure 4-20.
Master
Word clock OUT
Word clock IN
Slave
Figure 4-19: Slaving another digital audio device to the 828mk3 via
word clock. For the 828mk3 clock source, choose any source besides
word clock, as it is not advisable to chain word clock.
MOTU Digital Timepiece universal synchronizer
Audio
clock
Master Word clock OUT
Word clock IN
Slave
Figure 4-20: Slaving the 828mk3 to word clock. For the 828mk3 clock
source, choose 'Word Clock In' .
Don't chain word clock
If you have three or more digital audio devices that
you need to synchronize, avoid chaining their word
clock connections (OUT to IN, OUT to IN, etc.), as
this causes problems. Instead, use a dedicated
synchronizer like the Digital Timepiece or a word
clock distribution device of some kind.
Slaving to 2x and 1/2x word clock
All MOTU FireWire audio interfaces that support
96 kHz operation have the ability to slave to a word
clock signal running at either one half or one
quarter of their current clock rate. For example, the
I N S T A L L I N G T H E 8 2 8 M K 3 H A R D W A R E
828mk3 could be running at 96 kHz while slaving
to a 48 kHz word clock signal. Similarly, the
828mk3 could run at 88.2 kHz and slave to
44.1 kHz word clock.
Remember, the word clock signal must be one of
the following:
the same as the 828mk3 clock
■
half of the 828mk3 clock
■
Forcing a 1x word out rate
The 828mk3 can generate a word clock output
828mk3
signal that either matches the current system clock
rate (any rate between 44.1 and 192kHz) or the
corresponding 1x rate. For example, if the 828mk3
is operating at 192kHz, you can choose to generate
a word out rate of 48kHz. For details on how to
Other device
make this word clock output setting, see "Word
Out" on page 40.
CONNECTING MULTIPLE MOTU FIREWIRE
INTERFACES
You can daisy-chain multiple MOTU FireWire
interfaces on a single FireWire bus, with the
restrictions described in the following sections.
Most computers have only one built-in FireWire
bus (even if it supplies multiple FireWire sockets).
828mk3
Connect them as follows:
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