MOTU 828es, Руководство пользователя

Страница: 47 / 120

H A R D W A R E I N S T A L L A T I O N
47
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Resolving your MOTU device to an external
clock source
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Networking multiple MOTU interfaces
together
Synchronization is critical for clean digital I/O
Synchronization is critical in any audio system,
but it is especially important when you are
transferring audio between digital audio devices.
Your success in using the digital I/O features on
your MOTU device depends almost entirely on
proper synchronization. The following sections
guide you through several recommended
scenarios.
Be sure to choose a digital audio clock master
When you transfer digital audio between two
devices, their audio clocks must be in phase with
one another — or
phase-locked . Otherwise, you’ll
hear clicks, pops, and distortion in the audio — or
perhaps no audio at all.
Figure 5-18: When transferring audio, two devices must have phase-
locked audio clocks to prevent clicks, pops or other artifacts.
There are two ways to achieve phase lock: slave
one device to the other, or slave both devices to a
third master clock. If you have three or more
digital audio devices, you need to slave them all to
a single master audio clock.
Figure 5-19: To keep the your MOTU interface phased-locked with
other digital audio devices connected to it, choose a clock master.
Also remember that audio phase lock can be
achieved independently of timecode (location).
For example, one device can be the timecode
master while another is the audio clock master, but
only one device can be the audio clock master. If
you set things up with this rule in mind, you’ll
have trouble-free audio transfers with your
MOTU hardware.
SYNCING S/PDIF DEVICES
The 828es provides RCA S/PDIF digital input and
output. Your 828es and the other S/PDIF device
will sync to each other by way of the S/PDIF
connection itself for click-free digital transfers.
One device is the master, and the other device is
the slave.
Syncing the 828es to its S/PDIF input
When you transfer audio from the S/PDIF device
into the 828es, choose S/PDIF as the clock source
(item #13 on page 12) to resolve the 828es to its
S/PDIF input.
Syncing another S/PDIF device to the 828es
When transferring audio from the 828es to
another S/PDIF device, set the 828es clock mode
(item #13 on page 12) to any source other than
S/PDIF. Doing so makes the 828es the clock
master. When the other device records (or
receives) S/PDIF audio (from the 828es), it will
simply synchronize to the clock provided by the
828es S/PDIF signal.
SYNCING OPTICAL DEVICES
There are several ways to sync an optical device
with your MOTU interface:
A. Resolve the other device to your MOTU
interface
B. Resolve your MOTU interface to the other
device
C. Resolve both devices to a word clock source
Not phase-locked Phase-locked
Device A
Device B
Master
Slave
Master
Slave Slave