DigiDesign SYNC HD, Manual

Page: 44 / 103

SYNC HD Guide 38
From the SYNC Setup software utility
(Windows only):
„
Select the appropriate Digital clock reference
option from the Clock Ref pop-up menu.
If the chosen clock reference source is unavail-
able, or the current configuration is not valid,
the Locked LED on the right side of the
SYNC HD front panel flashes.
Additional Digital Clock Information
AES/EBU The SYNC HD AES/EBU In connector
only recognizes and uses the clock portion of an
incoming AES/EBU audio signal. All audio infor-
mation will be ignored and will not be passed to
the SYNC HD AES/EBU Out connector.
Word Clock Word Clock is a digital clock refer-
ence signal that runs at 1x sample rate (44.1, 48,
88.2, 96, 176.4, or 192 kHz). Pro Tools|HD inter-
faces have dedicated BNC-style Word Clock
connectors. A wide variety of professional audio
devices have Word Clock connectors, including
digital mixing consoles, DASH-standard digital
multitrack tape recorders and MDMs (modular
digital multitrack recorders).
Slave Clock (256x)
Slave Clock (or Super Clock) is a Digidesign pro-
prietary clock format used by legacy Digidesign
audio interfaces (such as 888|24, 882|20, 1622,
and ADAT Bridge) that runs at 256 times the
sample rate.
When using legacy interfaces with SYNC HD
and Pro Tools|HD, your master HD audio inter-
face (192 I/O, 192 Digital I/O, 96 I/O, or 96i I/O)
should supply Slave Clock to the first legacy de-
vice through its External Clock Out connector,
configured for 256x Slave Clock (see “Base
Clock” on page 60 for more information).
Pro Tools|HD audio interfaces are always con-
nected using Loop Sync (see “Clock for
Pro Tools Audio Interfaces” on page 8 for more
information).
LTC and Clock Reference
LTC can provide both positional and clock in-
formation from the same time code signal. LTC
cannot be read when the reference deck is
stopped, or playing back at slow or fast wind
speeds (roughly 10x playback speed). Pro Tools
will not lock until the LTC signal is close to play-
back speed.
While resolving to LTC as clock reference, the
SYNC HD provides five options to optimize
your system for different types of tasks. This lets
you choose between faster response (for when
fast lock-up time is critical), or highest sound
quality (during critical laybacks, for example).
The Session Setup window provides a sub-menu
for LTC Clock Reference choices. The five
choices provide different servo gain settings to
reduce the effects of jitter when locking to linear
time code. In Standalone mode, these settings
are also available from the front panel.
For additional digital clock signal informa-
tion, see “Digital Clock Signal Types” on
page 71.
Clock Reference LTC options in Session Setup