Do You Need A Synchronizer - MOTU 828mkII User Manual

DO YOU NEED A SYNCHRONIZER?

Whether or not you'll need a synchronizer depends
on your gear and what you will be doing with your
828mkII system. The following pages give you
specific information about common sync
scenarios. At least one of them will likely apply to
you. Here are some general considerations to help
you figure out if you need (or want) a synchronizer
for you 828mkII system.
You don't need a synchronizer if...
As explained earlier, the 828mkII's digital audio
clock must be phase-locked (synchronized) with
other connected digital audio devices to achieve
clean digital transfers between them. Can this be
accomplished without an additional digital audio
synchronizer? It depends on the nature of the other
devices, and what you want to do with them. You
don't need a synchronizer if the device has a way of
locking itself directly to the 828mkII's clock (via
ADAT lightpipe, S/PDIF or word clock), AND if
the device carries no sense of location in time. A
digital mixer is a good example: it can slave to its
ADAT lightpipe connection from the 828mkII, and
it has no sense of time; it just passes audio through
for mixing.
A stand-alone digital recorder, on the other hand,
does have a sense of location in time, either via
SMPTE time code or via its own sample address.
For example, if you want to fly tracks back and
forth between your computer and an Alesis hard
disk recorder while maintaining the audio's
position in time, the ADAT Sync port on the
828mkII lets you do so without a separate
synchronizer — and with sample-accurate
precision, as long as you're using AudioDesk,
Digital Performer, or other sample-accurate
software. Just connect the 828mkII directly to the
Alesis recorder (or other ADAT Sync-compatible
device) as discussed in "Sample-accurate ADAT
sync with no synchronizer" on page 26. But if you
also want transport control over the entire rig
I N S T A L L I N G T H E 8 2 8 M K I I H A R D W A R E
(including the hard disk recorder) from your audio
software, you'll need a MIDI Machine Control-
compatible synchronizer such as MOTU's MIDI
Timepiece AV, as discussed in "Sample-accurate
sync" on page 24. If you are simply using a stand-
alone recorder as a way to capture live tracks that
you then transfer in one pass into the computer, no
synchronizer is required because the tracks will
remain in perfect phase lock with each other as you
transfer them together. You can simply slave the
stand-alone recorder to the optical output from the
828mkII as explained in "Syncing optical devices"
on page 29.
Transport control from your computer
If you have stand-alone digital recorders connected
to the 828mkII, and they support ADAT Sync, your
audio software — if it supports MIDI Machine
Control (MMC) — allows you to control the
transports of everything from your computer.
Most advanced audio programs support MMC. To
do this, you'll also need an MMC-compatible
ADAT synchronizer such as a MOTU MIDI
Timepiece AV or Digital Timepiece. Synchronizers
like these allow you to play, stop, rewind and locate
all of your tape decks using the transport controls
in the audio software. If your audio software
supports sample-accurate sync (like Digital
Performer and AudioDesk), you can do so with
sample-accurate precision. The following pages
show you how to achieve MMC control, where
possible.
Continuous sync to SMPTE / MTC
The 828mkII can synchronize directly to SMPTE
time code. If your audio software supports sample-
accurate sync (like Digital Performer and
AudioDesk), it can also resolve to time code via the
828mkII. If your software does not support
sample-accurate sync, you need a dedicated
synchronizer, as illustrated on the following pages.
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