User`s guide

INSTALLING THE 896HD HARDWARE
25
SYNCING OPTICAL DEVICES
The word optical is our short-hand way of referring
to any device that connects to the 896HD via an
optical cable. But we make a further distinction: an
optical device is also one that doesn’t care about
sample location. An example is a digital mixer.
Since a digital mixer is not a recording device, it has
no sense of sample location like an ADAT does. An
ADAT can cue to a specific sample number (e.g.
sample number 43,478, 103) — as can any device
that supports ADAT sync, but most digital mixers
simply mix and process audio digitally, with no
sense of a specific sample location. There are many
other devices that fall into this category, including
digital effects processors, synthesizers, A/D
converters, and many more.
For ADATs or other devices that support ADAT
sync, synchronize them with the 896HD as
described in the previous sections of this chapter.
For optical devices, such as digital mixers, all you
have to do is make sure that their digital audio
clock is phase-locked (in sync with) the 896HD.
There are three ways to do this:
■ Slave the optical device to the 896HD
■ Slave the 896HD to the optical device
■ Slave both the optical device and the 896HD to a
third master clock (such as a Digital Timepiece or
MIDI Timepiece AV synchronizer)
ADAT Optical IN
ADAT Optical OUT
Digital mixer
or other optical
device
896HD
896HD
Clock Source setting =
Internal, or any clock source
setting except Optical. The optical
device slaves to the 896HD (via its
optical cable connection).
Digital mixer
or other optical
device
ADAT Optical IN
ADAT Optical OUT
896HD
With this setup, in the MOTU
FireWire Audio Console, choose
the Optical clock source setting.
The 896HD slaves to the optical
device via their optical cable
connection.
Figure 3-13: Three setups for synchronizing an optical device with the 896HD. You can slave the optical device to the 896HD or vice versa with
their optical connections. For more elaborate setups, you can slave both to a digital audio synchronizer like the Digital Timepiece. Don’t use
any of these setups for an ADAT or other optical device that records. Instead, see “Sample-accurate ADAT sync” on page 22.
Word Clock Out
MIDI Timepiece AV
set to Internal
ADAT Sync out
ADAT sync in
Digital mixer
or other optical
device
Word Clock IN
Computer with 896HD
bi-directional
optical
896HD
Clock Source setting =
optical
Mac
896HD
Clock Source setting =
ADAT 9-pin